stan.theblossers.net

DIY Glycol Power Pack (Chiller) for Beer Line Cooling

2011-03-28T10:43:00.004-04:00

When planning for my nano-brewery, I broke the project down into three categories: brewing, fermenting and end product storage/serving. While waiting on some parts to get the brewing operation ready to go, I decided to move forward on the serving portion of the project. Rather than bottle the beer - which would be a daunting task given the volumetric capacity of my brewing equipment - I decided to go straight to kegging. Many homebrewers end up kegging once their operations get more formalized, so I figured I would just skip to the end.

Since I currently don't have any product ready to keg, I put a local craft brewery's beer on tap. I quickly realized that the 10 foot run from my DIY kegerator to my tap tower was allowing the beer to warm up too much giving rise to foam and nasty warm beer!

In commercial tap systems, a refrigerated solution of propylene glycol is circulated along side the beer lines to keep the product cool in transit. I decided to replicate this method. After three attempts, I finally have a system that is working perfectly and replicates every aspect of a commercial system except one: the cost!

One of the primary features of a glycol cooled tap system is the trunk line. Generally, a trunk line consists of some number of product lines, wrapped together with a glycol supply and return line, then wrapped in an insulated jacket. I have five 5/16" beer lines and two 1/2" vinyl tubes for the glycol. These are wrapped together using cellophane packaging tape, then inserted into a length of pipe insulation. The pipe insulation has 1/2" thick walls.

Based on the length of the trunk line run, the insulation's thermal conductivity, and the tap box's heat gain characteristics, I calculated a very rough total heat gain of 250 BTU/hr. This is the amount of heat I will need to pull out of the trunk line and tap box in order to keep the product at 35 degrees from keg to tap. I chose 35 degrees so that once poured into a room temperature pint glass, the end result will be 42 degree beer.

The first iteration of my glycol cooling setup featured a simple reservoir in the kegerator in the form of a 5 gallon plastic pail. A submersible pump would send the glycol up a 1/2" vinyl tube in the trunk line, circulate it through a coil in the tap tower, then return it to the reservoir through a second tube in the trunk line.

The glycol started out at 35 degrees (the set temperature of the kegerator) but quickly rose to near ambient temperature. I suspected the submersible pump was adding heat to the glycol, so I switched to a different pump: a Taco (pronounced 'take-oh') cartridge pump designed for hydronic heating applications. Although still a wet-rotor pump, which I knew could impart heat to the coolant, it was not submersed. However, I got a similar result. Not having another pump handy, I decided to abandon the reservoir idea and go with an air-to-glycol heat exchanger in the kegerator.

Using an old motorcycle oil cooler and three high velocity computer fans, I constructed a forced air heat exchanger. Again, I used the same Taco pump and managed to achieve slightly better results. I measured about 44 degree coolant temperatures at the tap tower, but the temperature differential was insufficient to affect a timely drop in temperature in the product lines or tap tower. Additionally, the kegerator would only shut off for a few minutes each hour, when previously it would only run for a few minutes each hour to keep the kegs cold!

At this point, I knew that the heat exchanger was working and suspected the pump. Knowing that the next iteration of this project would take me the route of a compressed refrigerant route, I decided to go ahead and buy a new pump to see if the Taco pump was introducing an unacceptable amount of heat.

I selected a Little Gaint 2-MD pump as it is rated for mildly corrosive liquids, has an air cooled motor, and physical separation between the pump head and motor. It was the most cost effective option before going to something more exotic.

After testing the air-to-glycol setup again with the new pump, it was clear the Taco pump was not my limiting factor as I got nearly the same results with the new pump. I suspect the kegerator (a converted chest freezer) was simply not designed to vent the added BTUs the heat exchanger was introducing. Afterall, the interior and exterior of a chest freezer have limited surface area when compared to an actual air-to-liquid heat exchanger. Rather than chase my tail further, I began to explore the compressed refrigerant option.

Others in the home brewing community, as well as those looking for DIY options for aquarium chillers, have converted window A/C units for use as liquid chillers. Even small window air conditioners are rated 5000 BTU/hr and greater. Given I needed to move approximately 250 BTU/hr, I found that to be overkill. Had I went that route, I probably would have ended up with something only running for a few minutes each hour, and as any mechanical engineer will tell you, compressed refrigerant systems are most efficient in steady state running and not cycling frequently.

I did however find one web site that gave me the idea of converting a dehumidifier instead. Much smaller in regards to BTU capacity, and without the potentially troublesome fins on the evaporator (cold) coils, I immediately decided to attempt this route!

I began by disassembling a 20 pint/day that I had laying around. It was too small to effectively dehumidify my basement, so it was no real loss if it didn't work. Normally the evap coils are infront of the condenser coils. Ambient air is drawn over the evap (cold) coils, thereby condensing water out of the air, then through the condenser (hot) coils to cool the compressed refrigerant, then exhausted to the room.

To directly utilize the cold produced by the evap coil, I carefully bent the coil down and into a 10 qt cooler that would serve as the glycol reservoir. The aluminum coils were very easy to bend. It freaked me out a little, so I was wearing a face shield and heavy welding gloves just in case the R134a got "liberated"! Regardless, some gentle persuading and the end product looks like this:

The initial test was to hot wire the dehumidifier controls and turn it on with a tiny fountain pump in the cooler circulating the glycol. In 20 minutes it had dropped the temperature of the solution to 18 degrees. At 30 minutes, the solution began to slush at 9 degrees. There was also no lid on the cooler at the time, so I don't know how much heat gain I got from just ambient air. Regardless, a casual calculation based on temperature change put the unit at around 1200 BTU/hr, meaning I should be able to run at about a 20% duty cycle to chill my lines.

Having had success with the initial test, I cut the lid as necessary, installed plumbing and hooked it up to the pump. After only 10 minutes of running, my glycol line temp in the tap tower was 27 degrees. Keep in mind though the glycol was still chilled from the first test. In fact, I had transferred it back to the jugs so I could do my plumbing and such, and after an hour of sitting in the jugs, the surface of the jugs were still cold enough to form frost!

After 35 minutes of running, the glycol was 20 degrees and the beer line was 43. At that point I started to manually cycle the dehumidifier on and off (so as to not freeze the beer), and ended up achieving 35 degree beer temp at the tap after about 50 minutes. Poured into a pint glass, a perfect 42 degrees!

I've nicknamed my creation R2-GlyCool, since I think it looks a little like the famous Star Wars droid R2-D2, but with a "beer belly" (the red cooler/glycol reservoir). I still need to insulate the glycol lines that supply the trunk line as they form an amazing amount of frost, and of course, waste energy.

With regards to power consumption, the pump has a steady state draw of about 100 watts. The dehumidifier has a steady state draw of about 220 watts. Currently, the pump runs 100% of the time (which I don't expect to change), and the compressor with uninsulated lines runs 50% of the time. That averages out to 153 KW-hr/month or about $16/month at my current rates. Naturally that will drop once the lines are insulated.

The reservior temperature is regulated by a very simple PIC microcontroller, 1-wire temperature sensor and solid state relay. I plan to improve on this design so as to run multiple pumps to chilled fermentation vessels for hefeweisens and lagers.

I also have a redesign of the tap tower in mind that, by coupling the lines more closely and eliminating air space, will further improve efficiency and temperature stability.

I should also note that I had a brief flirtation with a thermoelectric Peltier cooler in the tap tower that totally didn't work. Without forced air (resulting in noise) over the heat sinks, it performed very poorly. I didn't include details on that in this post as it was such an under performer, I don't think it would ever be suitable for this application, nor was there anything more to learn from that experience than that.

Update 3/30/2011: The lines are now fully insulated and the compressor is cycling on and off at only a 16% duty cycle! Now if only I could find a more efficient way to circulate the coolant....

Homebrewing: The Next Challenge

2011-02-03T17:32:00.001-05:00

For too long I've been a connoisseur of beer but, until recently, never engaged in the manufacturing process. As my twitter followers know, about a month ago, I made my first batch using malt extract and a recipe from a local brewing supply store. If I learned one thing from that batch it is this: brewing beer is easy!

I realize there are many that would argue that opinion (or perhaps even punch me for saying it) but lets face it: people have been brewing beer in one form or another for thousands of years. Long before the Internet existed to enable us to readily exchange information, and long before we understood the role yeast played people were making passable beverages. I contend that, with the correct application of research, discipline and DIY desire, anyone can brew beer. Naturally that begs the question: what am I going to do differently?

It is my goal to take the features of large craft breweries (minus the hipsters and dreadlocks) and downsize them to home brewing capacity levels, while at the same time take advantage of the flexibility afforded to the home brewer but limit the hobbyist-grade errors.

My first batch was 1 gallon. Yes, really. It was a lot of work and waiting for 5 pints of final yield. I am immediately going to 5 gallon batches. Still, not all that impressive as many people brew that size and larger. To take it step further, I'm also introducing automation, advanced equipment and commercial techniques into the mix. Additionally, most of my product will never see bottles. I'll also be building a bar that houses kegs in a converted chest freezer, commonly known as a "kreezer".

So, to summarize, one month ago I knew very little about the process. Currently, I'm building an all grain dedicated brewing facility that operates on exactly the same concepts as a commercial craft brewery. As I often say, "anything worth doing is worth over doing!"

My brewery (which will occupy a spare room in my basement) will feature:

A two kettle system - one for a boil kettle which doubles as a hot liquor tank, and another for a mash lauter tun
A plate heat exchanger which will use heat from the HTL to warm the mash water
A single, electronically controlled and ignited burner under the boil/HLT
Dual pumps for moving fluids through the heat exchanger and between vessels
A custom designed and programmed controller that will manage the entire process
A complete purpose built plumbing system with large sink and ejection sump
Organized storage for carboys and perhaps other fermenters in the future

The end product will be stored and force carbonated in 5 gallon kegs, commonly known as Cornelius kegs. I intend to build a custom bar around a chest freezer to serve beer from those kegs. More on that as that part of the project starts to take shape.

At this point, I've mainly been accumulating parts. I have the kettles, burner, gas works, and many of the electronic parts. I'm currently waiting on a 50 plate heat exchanger and my temperature sensors for the controller. I will be updating my twitter feed as individual developments occur, and posting to this blog as portions of the project are completed. Also, check out my brewing Picasa web album for some great pics.

Target filesystem doesn't have /sbin/init on Debian Lenny after Upgrade

2010-12-19T13:15:00.003-05:00

Apparently this "target filesystem doesn't have /sbin/init" is a common issue with Debian and derivatives such as Ubuntu. The issue manifested its self after I performed a round of security updates on my server, which included a kernel update. I think that perhaps what lead me to this particular error was that I use a LVM based Linux software RAID1 for my boot partition.

After trying various fixes, most of which were intended for Ubuntu, here's what worked for me:

I booted the system off the Debian installer CD I originally used and selected "Rescue Mode" in the boot options.
Proceeded through the options, selecting the defaults (network config, time zone, etc)
Selected the option to open a shell at /dev/boot/root (your path might be different)
Ran "lilo" to update the boot sectors on both /dev/sda and /dev/sdb (my RAID drives - LILO detected them automatically).
Rebooted

That's all it took. I've had issues before during kernel upgrades where I'd get various boot-time error messages. Again, I think it is due to LVM on software RAID. Regardless, I'm publishing my fix in the hope this helps someone else out!

HTC Hero on Sprint: A Week in Review

2009-11-06T14:10:00.000-05:00

About a week ago I bought a new CDMA HTC Hero with Sprint service. Prior to buying the phone, I checked the reviews, watched some You Tube videos, etc. While the reviews were less then stellar, I failed to see examples of any of the issues people complained about on the You Tube videos. Specifically, one YouTuber stated the phone was slow but failed to show any example of this in his video. Later in the video he launched a task manager only to show about 15 different processes running simultaneously! I think my Core 2 Duo laptop would run slow with 15 apps running concurrently!

Many reviewers feel the need to complain about a product, or they somehow aren't doing their job. I plan to simply serve up the facts and observations I've gained with a week of actual use:

First, some background. I was a happy Alltel customer until they sold to Verizon Wireless. Besides Verizon's patent troll attacks on Vonage, their plans are expensive and, at least in the past, their customer service has been less than stellar. While Verizon allowed Alltel customers to stay with Alltel plans, I just didn't want to fork any money over to a company I didn't choose in the first place. So, I voted with my dollar and headed for Sprint.

I was initally going to buy the HTC Hero on Oct 11 when it came out, but shortly before the release, Sprint announced the Samsung Moment. The Moment's spec sheet looked impressive: 800 MHz processor, optical track-pad, slide out keyboard, etc. I didn't mind that they only offered bone stock Android 1.5 vs HTC's Sense overlay. So I waited until I could read some reviews of the Moment. Low and behold, Samsung doesn't have a good reputation for supporting or upgrading their phones. Not a good thing with a smartphone!

So, off to Best Buy I went to pick up the HTC Hero without having to deal with a mail-in rebate otherwise necessary at a Sprint store. In addition to the lack of mail in rebate hassle, Best Buy also offered a $50 coupon to their Reward Zone members (free membership). Sprint is also currently offering a referral bonus to both the new customer and the referrer. Even though nobody referred me, I still dialed #REF from my new Sprint phone and put in the phone number from one of my friends also on Sprint. I will get a $25 VISA debit card in the mail, as will she. This brings the price of the phone down to $111.74 total with tax. With Verizon's announcement of the HTC Eris (an ugly Hero) at $99, I'm feeling pretty good about my choice, also considering I will save $360 per year on my Sprint plan vs. a comparable VZW plan.

The Good

Ultra loud speakers, both on the earpiece and speakerphone
Works well with my Jawbone Bluetooth headset
Seamless integration with email, SMS, Google services, and Twitter
Excellent web browser with multi-touch zooming
Excellent contact management built into HTC's Sense UI
Great battery life - with heavy use I can only drain it to about 40% in one day
Amazing GPS receiver sensativity - on the first floor of my two story house I can get a GPS lock in about 3 seconds
Visual voicemail - doesn't consume airtime while checking voicemail
Very nice album app with multi-touch zoom

The Bad

No task/todo list functionality built in
Lacks camera flash
No belt pouch included
Built in SMS app is weak
Built in mail app messes up my IMAP folders - not configurable
Can't remove stock apps... Don't care about the NFL or Nascar! Give me my megabytes back!

For most of the "bad" above, I've found some solutions.

To add todo list functionality, I've downloaded Astrid from the android market. A free app, it handles most of what I need, but falls a little short in some areas. Please, HTC or Google, just rip off MS Outlook's task functionality and include it in Android market!

The fact the camera doesn't have a flash doesn't really bother me. Usually if I try to take a friends picture in a dimly lit situation, the flash just makes them squint. Incidentally, the Hero's camera does pick up infrared. The thought has crossed my mind of creating a hand held IR LED light for just such an occasion.

The lack of a belt pouch is just a cheap out on Sprint/HTC's part. Where am I supposed to put this thing? I my pocket? Really? Fortunately, eBay has plenty and I found one that fits well for $9.95 delivered.

One of the first things I did was install Handcent SMS from the Android market to replace the weak included SMS app. Handcent is free and has way more features. Nuff said.

I have a number of email accounts, all hosted at Google Apps. I wish the built in Gmail app could handle them all, but alas, it only deals with the default account used to setup the phone. Hopefully the upgrade to Android 2.0 will fix this, because the built in mail app is a little weak. While it does work, it creates its own IMAP folders and I have to routinely log into the Gmail web interfaces for my accounts and clean out the Sent and Trash folders it created.

Finally, I hate having apps on the phone that clutter up the menus, and take up space. I realize Sprint wants to subsidize Nascar, but I really couldn't care less. Give me the option to delete that junk! NFL too.

While there are some things I would change, none are deal breakers. And not once have I had an issue with the phone being slow. I don't know what others are running or asking their phones to do, but I find that if I remember that it is a phone and not a desktop computer, I'm fine.

In summary, to put it in eBay vernacular: Would buy again! A+++++++++

Waking Up to X10, Linux & Cron

2009-10-11T11:04:00.000-04:00

Anyone who knows me will tell you I am not a morning person. Maybe it's the shock to the system brought about by an alarm clock blaring, naturally followed by the squinted eyes when I flick the lights on. Especially in the winter when the days are short, waking up before the sun is a pain, but a necessary part of life. However, using a little technology and creativity, I hope to lessen the dread of the morning routine.

I've been a fan of X10 power line control devices for a very long time. I've used them in combination with wired remotes, RF remotes and more recently, the CM11A computer interface. The other day, I decided to beat the winter morning blues by upgrading my system slightly and implementing my own sunrise!

While there are turnkey systems available (at sometimes great expense) to provide this level of automation and customization, I wanted to use the components I already had in place. The complete system consists of:

LM465 soft-start lamp modules (3 for my needs)
CM11A computer interface
My all-purpose Linux server
Cron and a uber simple shell script
"Heyu" command line interface for the CM11A

For reference, the shell script is as follows:

for (( i=1; i<64; i++ ))
do
/usr/local/bin/heyu xpreset f2,3,5 $i
sleep 20.2
done

/usr/local/bin/heyu on f4
/usr/local/bin/heyu off f6

The cron job is setup to kick off at 6:30am Monday through Friday. The shell script begins by sending a command using heyu to the CM11A to tell the LM465 modules to come on at a brightness of 1 (out of 63). Then, it delays for 20.2 seconds, then repeats the loop for a total of 63 iterations, each time increasing the brightness of the lights by one level. The final two steps in the script are to turn on my espresso machine to get the boiler warm and turn off my white noise generator.

So, why the 20.2 second delay? My goal is to have the entire process take 25 minutes. Each time heyu sends the command, it takes about 3.7 seconds to run. Those 3.7 seconds plus the 20.2 second delay times 63 iterations equals 1505.7 seconds, or about 25 minutes. The end result is at 6:55am the lights are on at full brightness and by 7:00am the boiler in my espresso machine is hot and ready to go!

All of the components for this project (other than the Linux server) were sourced from eBay for a total of about $45.

A note regarding the LM465 modules: there are two versions of these modules. The first generation is not "soft-start" enabled, while the later are. The real kicker is there was no change in model number or any other external markings making it very difficult to tell which you are buying. I bought my LM465's off of eBay where the seller specifically stated they were the soft-start variety. For this implementation, I am not using the soft-start feature though, but rather other features that come along with the upgraded program in the internal microcontroller. These later modules respond to an extended set of X10 commands, which enables the "turn on at level 1" feature. Previous models would only turn on to full brightness.

Telescopic Way Cover for X3 Mill

2009-10-10T12:28:00.002-04:00

Owners of these small mills will know that the Y axis is the most vulnerable to metal swarf and contaminants as the ways can become exposed while machining. The X axis is never exposed directly, and the Z axis is vertical which provides some protection as the chips just fall off. Given I have CNC converted my X3 mill, and have added flood coolant and ball screws, it is even more critical for me that the Y axis be protected.

Several months ago I noticed the CNC version of the X3 Mill from Sieg had been released. Harbor Freight sells it under the name KX3 (HF P/N 66051). In the pictures I saw of it elsewhere on the web, I noticed several very nice features. One in particular that interested me was the telescoping metal Y axis way cover. I went out on a limb a bit as I was unsure if the part would fit my X3, but I was betting that Sieg used the same castings for the table and column - the two parts the way cover had to mount onto.

After a few unsuccessful attempts to get a price or availability info from Little Machine Shop (retailer of parts for Chinese mills), I contacted Harbor Freight's tech support division and requested information on the way cover using the parts diagram in the back of the manual for the KX3 (available from Harbor Freight's web site). I was pleased that they were able to get me a quote in just a couple days so I ordered it up.

It took several months for it to arrive, but it was shipped from China. Also, since these mills were new at the time, I expected a delay in the supply chain for spare parts.

Upon arrival I test fitted it and, to my delight, it fit perfectly! It is now mounted on the mill and works perfectly. To mount it I only had to drill and tap a total of four holes. Some small 10-24 cap screws were perfect for the job.

Update 3/23/2010: I had someone inquire about this and I found that Harbor Freight apparently no longer lists the KX3 on their web site. If you want to order a way cover for your own X3, when contacting Harbor Freight's tech division (tech@harborfreight.com), the two key pieces of information I used to order mine was:

The part number for the KX3 mill: 66051
The item number from the parts diagram for the way cover: 177

Just remember, your results may vary and I make no guarantees on fitment on your setup. Best of luck to you!

New Geckos are In!

2009-02-09T17:35:00.003-05:00

Well, the new Gecko's are installed and man are they nice!! I cannot believe how smooth the motors both sound and move. There is no perceivable resonance anywhere in the range of speeds from dead slow to 120 inches/minute. Also, the motors seem to have far more torque than with my home brew design. The head is traversing easily at 60 IPM (no counterweight) and the table is humming along happily at 120 IPM. I will have to fiddle with the timing settings in EMC2 however, as now it is reporting real time latency problems when it wasn't before. My drives were running at 20 micro steps, whereas the Geckos are fixed at 10 micro steps. So, my actual step rate has been cut in half, but EMC2 is still complaining.

On a side note, it does crack me up how uptight some folks seem to be with "real time" computing being necessary for CNC operation. Especially in a hobby setting, using Chinese machinery and home-made components, does nanosecond accuracy really matter? Clearly, MACH3, the Windows based competitor (which is not real time) seems to handle accurate machining just fine without all the "real time" voodoo. Sometimes I wonder if geeking out on precision timing is more an exercise in how-geek-one-can-be rather than practicality. Far be it for me, however, to question the efforts of the great folks that wrote EMC as I would have to shell out cash for different software if it weren't available. I realize EMC has to fit many applications and that, perhaps, some of those need that real time precision. On the other hand, I wish there were a "hobby mode" it would run in where it would be a little less sensitive!

Anyway, back to the topic at hand! To mount the Geckos, I used a couple surplus heat sinks I had laying around. They were of sufficient size to mount two units each. (I have enough room left to mount another drive for an "A" axis in the future.) On the opposite side of the heat sinks from the drives I mounted small fans to add forced cooling. Each assembly is mounted on 1.25" standoffs. That leaves about 0.25" of clearance between the fan and the mounting panel in the controls cabinet. The drives remain cool to the touch while running the axes at their max speeds for an extended period during my tests.

With regards to wire routing, I have managed to organize everything into a three-layer design. The signal wires from the computer for step and direction are routed against the mounting panel. They are held there with tie wraps and 3M Command Strips. The power supply wires are rigid, so I've bent those into place so that they are on the same plane as the drives. At the top of the photo they run back toward the panel and are also held in place with tie wraps. That gives approx 1.25" of clearance between the power supply wires and the signal wires in the areas where they overlap. Finally, the feeds to the steppers come out of the drives and towards the camera in the photo. They then exit through the top of the cabinet. This gives about 1" of clearance to the power supply wires and 2.25" to the signal wires.

In addition to the step and direction signal wires, I've also wired the "DISABLE" input on the Geckos to the "Amp Enable" output of EMC (optically isolated, of course). This is nice because the drives do not move until enabled by EMC. In other words, they don't jitter while the computer is booting and they immediately cease operation if there is a software following error or E-STOP is activated. It has also been nice during testing as, if I close out of EMC, the drives are powered down so they aren't consuming power, putting out heat or causing the motors to "sing". Although this doesn't replicate a true "E-STOP" where it removes power from the drives, I believe it is sufficiently safe for my needs.

Overall I couldn't be more pleased with these little buggers. I wish I hadn't screwed around with rolling my own design in the first place, but that is part of the value of these sorts of projects - learning the hard way!!

Here's a quick video of it in action. Sorry, but my digital camera only allows for 30 second movies - I'll upgrade in the future! The program running is the "EMC2 AXIS" logo program that comes with EMC. Unfortunately the time limitation only let's it get through the "EM" but you get the idea. Who would have thought a Sharpie would fit so well in a drill chuck?!

Ball Screws and Stepper Drives

2009-02-09T17:28:00.005-05:00

I just couldn't go a whole year without posting something! As was the case in previous years, summer rolls around and I'd much rather tear around outside in my car or on my motorcycle rather than be closed up in the shop. This past year was no different, but since the snow started to fly, I've been busy!

The ball screw conversion of all three axes is complete. For this I used Nook ball screws. The 9x20 lathe was quite a trooper when it came to machining the ball screws and bearing/pulley mount ends. I was also able to make nice bearing blocks for the angular contact bearings and, using the equipment I have, there is no measurable lash in the bearing setup. Currently I am only using one nut on each ball screw, which results in about 0.005" of backlash. I'd like to get that down to 0.001" - 0.000" if possible. I bought two nuts for each axis, and intend to make my own preload assembly with belville washers.

My method for machining the ball screw ends is a little different than most. Rather than try to hold tight tolerances while machining that super hard ball screw material, I took a different approach. I drilled the end of each length of ball screw and tapped it for 5/16 threads. I then took some precision 12MM rod (the bore diameter for my angular contact bearings) and turned that as necessary and completed it with male 5/16 threads to screw into the ball screw. I locked them together using red Loctite and that has worked quite well so far, with the exception of the Z-axis. I'm guessing the forces on the Z-axis are too severe and cause the threads to loosen up. I've though about drilling and pinning the threads, but I'll probably just use some JB weld in place of the Loctite.

So, the mechanical stuff has been pretty easy. A bit tedious at times, but a learning experience and quite rewarding in the end. The part that has had me swearing and scratching my head are the stepper drives!

As I mentioned in an earlier post, the microcontrollers on the drives were rebooting randomly and causing lost steps and other weirdness. I thought I had that licked, but the problem has cropped up again. I've tried a few things to remedy the problem, but in the end I have to admit that I'm giving up on my own stepper driver design. I've ordered three Gecko G251's and I hope to put the controls chapter of the CNC to bed once and for all.

With regards to the controls, there have been some minor successes. I have upgraded the PC to Ubuntu 8.04 and freshly installed EMC2. The system seems much more responsive overall. I've also got a Logitech game controller integrated with the system so that I can jog the axes at variable rates using the analog direction sticks on the game controller. Also, I've gutted the X3's original electronics and wired up everything to the controls cabinet. The original green "Power" light comes on when the system powers up and the "Fault" light extinguishes when EMC is ready to control the mill. Also, the factory E-STOP button sends an E-STOP input to EMC. That will be improved in the near future to also send a signal to the "DISABLE" input on the Gecko G251's as well as short (activate) the "inhibit" input on the spindle motor drive.

However, the recent achievement that I'm most pleased with is the mills new "stand". The wobbly wood platform it was sitting on just wasn't going to cut it and was making me nervous. Since I had to disassemble the mill to mount the ball screw hardware, I decided to grow my welding skills. I've created an extremely rigid stand for it using mostly angle iron. It not only easily supports the mill, but neatly houses the controls cabinet in a new horizontal orientation. It is rigid enough that I can grab the stand and drag it around the shop to get to the different areas of the mill without any flex. That's with almost 400 lbs of cast iron and probably another 75 lbs of controls and cabinet.

In addition to the items mentioned above, also on the to-do list is coolant plumbing. Fortunately there will be no complex engineering there! I'll simply be reusing parts from my old mill.

Removing Dykem

2008-03-25T17:27:00.001-04:00

I couldn't find this with a quick Google search, so I thought I would post my new bit of knowledge here.

To remove Dykem use brake cleaner! It is available at any auto parts store, and is dirt cheap. I didn't want to buy a special "Dykem remover" solvent since this is a hobby and I probably won't go through it very fast. In my search to find an alternative I tried a number of solvents, but brake cleaner seems to remove Dykem better than any of them. Given that I do brake jobs on my own vehicles as well as for my friends and family, I always have some laying around. Be careful though as it can etch certain plastics readily.

X3 Unpacked, Cleaned & Mounted

2008-01-11T17:27:00.001-05:00

Delivery of the X3 went off without a hitch. Rachel and I picked it up at the UPS Freight depot at about 5:30pm. By 8pm it was disassembled and in the shop waiting to be cleaned. Disassembly was reasonably straight forward, and it broke down into very manageable chunks. That enabled me to get it into my basement shop without any lifting equipment.

Cleaning was also straight forward. WD40 did an excellent job removing the Red China grease. I per fer it for cleaning jobs such as this as it contains corrosion inhibitors, leaving the shiny cast iron protected as well as clean.

The only thing I wasn't truly prepared for was just how heavy the X3 is. With the exception of the sheet metal column cover, every stinkin' component was heavy. Being the first massive piece of machinery I've bought and had to move and clean, I wasn't fully mentally prepared for what to expect. No troubles though, as I think the heaviest component comes in around 75 to 100 lbs.

Currently the X3 is "mounted" using the included leveling feet, and is sitting on top of a sheet metal tray. Given I don't have sheet metal bending abilities (yet) I ringed the pan with 3/4" aluminum angle stock, and sealed it with silicone. It will serve as a chip pan to begin with, and later the drain pan for the coolant system (more on that later). The sheet metal is screwed to a 2x4 based stand which does a fine job of supporting the weight of this beastie. The controls cabinet from my X1 (micro mill) CNC project is already mounted to the side of the stand.

The direction I'm going with this mill's CNC/coolant containment enclosure will be a little different than the X1. Rather than a fully enclosed version, I'm going to use strategically placed splash shields that will direct the large majority of coolant and chips into the lower tray. It will then drain into the filtering and recirculation system from there. This mill is simply too large in my mind for a full enclosure. By scaling down the enclosure I think I can save some money and speed up time to production.

As I said in a previous post, this will be getting a pulley driven ball screw system run by steppers. I'm going to reuse the 276 oz-in steppers from my X1 project. I'll probably go for 2 to 1 reduction on the X and Y axis, and perhaps 3 to 1 on the Z axis. I'm not sure if a counterweight will be needed for the head, but I suspect not with that level of reduction.

Before I get rolling on that though, I'm going to do some testing on the steppers. I'll be looking for practical upper RPM limitations, as well as realistic torque ratings at various speeds. That will give me a better idea of what gear reductions I'll need, and what traverse speeds I can expect.

All in all, there's no doubt that I'm starting out with a far superior machine this time. I'm looking forward to spectacular results!

Realizations, Decisions & Upgrades

2008-01-02T17:21:00.004-05:00

The other day, while trying to mill a counter bore in some steel, I came to the realization that my Micro Mill wasn't cutting it (pun intended). The upgraded spindle drive system was definitely up to the task, but the rigidity of the Z-axis was frustrating. Even with the new brass gib, I have to have the gib screws so tight that the 276 oz-in stepper cannot reliably move the Z-axis.

The Z-axis is a known weak point on this machine. With the somewhat non-standard pitch on the lead screw and the slop in the dovetails, milling with it has always seemed like a chore to me. I suppose one could argue that "I got what I paid for" in that it is a small, hobby sized machine, but none the less, I expect more.

After some failure analysis, I came to the conclusion there were really three factors at play. First, my Z-axis lead screw is slightly bent. That really doesn't come into play until near the lower limit of travel, but it is still a factor. Second, the dovetails do not seem to be very precisely machined. There is some binding at the lower limits as well, even with the bent lead screw disconnected. Third, there is some binding in the stepper drive setup, which is parasitically wasting power.

The cost to fix these items is significant, more so in time and frustration than in cash cost. And obviously, after spending more time and money on this machine it would, at it's core, still be a "micro mill." Do I want do upgrade this machine further, or is there a better route? What are other people upgrading to when they outgrow this mill?

Time for a decision!

I have to admit, a while back when the Sieg X3 mills started showing up in the US, I thought they were an awesome machine. Inch lead screws on all three axis, beefy square column, bearings on the hand wheels, and a standard R8 spindle were all appealing features to me. Initially they were pretty expensive and there were only a few places to get them. I had planned on checking back in to these machines once the newness in the market wore off, but hadn't gotten around to it.

So, I started my research there, and have to say it pretty much ended there. Most of the comments on the various forums were very favorable. The videos on YouTube of it operating were very impressive.

There are really few options in that class of machine. The Super X3 has some nice features, but given that my machine will be CNC'd, the added features (and associated cost) of the SX3 are not needed. I certainly didn't want to go with an X2 or Mini Mill, as I knew it would need upgrades right out of the box. I've been down that road with my X1 and didn't want to travel it again. On the other end of the spectrum is the Rong Fu 45, which is larger, and more expensive. Given the leap I would be making going from the X1 to the X3, the Rong Fu seemed like overkill. Then there are, of course, the round column mills. The only "accurate" Z-travel those offer is in the quill, which doesn't lend well to CNCing. Also, as the quill is extended, rigidity is reduced. Not an issue for drilling necessarily, but definitely for milling.

The X3 it is!

I decided to get mine from Grizzly Industrial. It is their part number G0463. I missed Grizzly's holiday sale by one day, so I emailed them to see if I could get the holiday pricing. They were very willing to accommodate me and, after some prodding, even threw in some accessories to sweeten the deal. It's on a truck, headed my way.

The initial upgrades will be ball screws on all three axis and stepper based, pulley driven CNC. I will be recycling the controls and motors from the X1, so the road to full CNC should be a short and frustration-free trip!

Return of the X1

2007-11-03T17:15:00.016-04:00

After some downtime, the mill has returned with added glory! A touchscreen LCD on a swing arm and new controls cabinet make the mill completely self contained. Also, I've added home switches for automated homing and interfaced the PWM component of EMC 2.1.7 to the spindle's speed controller.

The touchscreen was truly an indulgence. I wanted an LCD so that I could mount it on an arm hanging off the enclosure, but found a cheap touchscreen on eBay and said "why not!" The seller did not list it with very much detail, so it was a bit of a risky buy - not being sure if it would interface with Linux - but it has a standard Micro Touch USB controller in it, so I was able to make it work.

The new controls cabinet was the primary achievement though. It allowed me to consolidate all the electronics into a common housing, and by tying the metal cabinet to ground, isolate the electronics from noise generated by the steppers, spindle motor and especially the coolant pump. That cheap Harbor Freight pump really generates some EMI.

In the numbered image above:

Incoming AC power switched by a master switch on the front of the enclosure
Mini-ITX motherboard running Ubuntu 6.06 and EMC 2
5V DC power supply for logic circuits not run by the PC
Breadboard for opto-isolated circuits and other interface logic (home switches, coolant pump and spindle PWM interfaces)
Stepper controllers
Solid state relay for coolant pump
Spindle speed controller, driven by PWM signal output from EMC
720W ~48V unregulated power supply for steppers

Note the breadboard I'm using for some interface circuitry. I've had a few comments on it from various folks asking why I would use something designed for temporary use in a seemingly permanent application. The main reason is that nothing I do ever seems to remain permanent! I'm always tweaking, upgrading and modifying my designs in one fashion or another. In fact, I spend more time building the machine than using it many times. After all, it's not the destination, it's the journey - at least for me! So, rather than make a printed circuit board, use a perfboard, or wire wrap it the slam-dunk method was a breadboard. Additionally, if I blow out an opto-coupler for some reason, it will be easy to replace.

With the added space the cabinet provided, and since everything is now in a common housing, it was easy to add some needed features to the mill. Primarily home switches, and put the spindle and coolant pump under computer control. The home switches allow me, for example, to set the offset of the vise from the home position and then I'm quickly able to locate it between power cycles. The spindle and coolant pump automation make the mill completely hands off. I can start a job and walk away and when done, the computer powers down the coolant pump and spindle. Eventually this will also allow me to attempt rigid taping, etc.

Also, check out the video below of the spindle automation. Basically, the mill moves into position, starts the spindle, enlarges a hole in a Radio Shack project box, retracts, then turns off the spindle. I think it was about 6 lines of G-code, but it gets the point across.

As always, please feel free to contact me with any questions or comments on my setup!

Touchy Touchscreen

2007-07-22T17:14:00.002-04:00

I finally got around to attempting to hook up the 15" touchscreen I purchased off eBay to the mill's PC. I was initially quite impressed as Ubuntu 6.06 recognized it as a Micro Touch screen and loaded the appropriate USB driver right off the bat. What I didn't realize is what a pain it was going to be to get X to recognize it as pointing device.

To make a long story short, I searched the net for any and all documentation regarding this and found very little. Google just wasn't giving me the results I wanted. I finally pieced together enough information to get it working, but I wish Google had sent me to this web site first. That is exactly the procedure I ended up using. Had I found that site earlier it would have saved me many hours and curse words!

Enco Phase II+ Quick Change Tool Post for 9x20 Lathe

2007-07-15T17:12:00.000-04:00

Rather than mess around with shims to get my lathe tooling centered to the chuck, and to enable me to use boring bars and parting tools, I purchased a Phase II+ quick change tool post from Enco. After reading a significant amount of information on how to get this piece to fit on the 9x20 lathe, I was a little apprehensive. However, after about two hours of shop time it is mounted and works great!

The first thing I learned is that making an adapter to get the new QCTP to work with the stock tool post stud is easier than I thought. I simply took the stud that came with the new post, cut off all but about 0.75" of material below the threads on one end, then drilled and tapped it for M8x1.25. That enabled me to screw that adapter onto the stock stud, slip the new tool post over it and use the included nut to sinch it down. Much easier than I thought it would be!

The other thing I learned is that 1/2" tooling seems to work fine for me without modifying the compound slide. I had read elsewhere that this modification was necessary, however I've got the tool centered and everything seems to work fine. Perhaps I'm missing something, but if so, I'll likely discover it in the future and, at which point, I'll post my mistake here! :-)

New Member of the Family: 9x20 Lathe

2007-06-28T17:12:00.000-04:00

As luck would have it, a buddy of mine decided to part with his Harbor Freight 9x20 lathe for a price I was willing to pay. I'm glad I have it and can't wait to make long stringy chips!

I must say though, that I think I should have bought a lathe first. Realizing that Chinese machine tools are essentially elaborate kits (without instructions), it would have been nice to have the tools handy to make new rotating and/or power transmission parts myself. If I had to do it all over again, there is no question in my mind that I would be better served by getting the lathe before the mill. Although, I think the mill will likely be used more often, the lathe is more of a necessity or rather a more "basic" tool.

The mods to the lathe will be pretty tame to begin with. First and foremost will be the 4-bolt compound slide mounting plate. That seems to be a priority for many folks so, drawing on their experience, it will be mine too. I may just buy one rather than make it myself to speed along the time-to-production for my new lathe. A quick change tool post (Enco Phase II piston design) will be next for sure.

My first two projects will be: a custom espresso tamper for my recently acquired espresso pot, and new pulleys for my mill. As I stated in a previous entry, I basically was making lathe parts on my mill by using the CNC's circular interpolation to cut pulleys. This time around I'm going to buy some HTD5 timing pulleys and taper bushings (probably from from econobelt.com) and open up the ID of the pulleys on the lathe. As I infrequently change speeds on my mill, I'm throwing out the step pulley concept in favor of a higher HP capacity drive system. The variable speed DC motor can take care of variance within whatever range the pulleys put me at.

X1 Flood Cooling

2006-06-25T17:04:00.002-04:00

It has been a while since my last post, but that's cuz I've been a busy little basement engineer! :-) I built an enclosure for the mill and implemented a flood cooling system. In addition to the cooling and lubrication benefits of a flood system, it is nice to keep the chips contained to a controlled area.

Basically it is an enclosure made from 3/4" MDF sitting on a base made of 2x4's.

What spurred me onto this was, while trying to make my pulleys, I discovered that the slow feed rates necessary with my ad hoc belt drive caused the 2024 aluminum to almost flake off. Airborne high strength aluminum dust can't be good! So, to solve that problem (plus gain other benefits) I built the enclosure.

The bottom is lined with 1/8" thick rubber that can be had from McMaster-Carr, 4 ft worth of P/N 86795K43. The filter setup is a food storage container with the bottom perforated, a large hole cut in the top and some nylon mesh sandwiched between the top and bottom for filtration. The mesh is also from McMaster (9318T48) and has .002" openings. It is about 40% open so flow isn't an issue. It doesn't let any solids past! The only issue I've found is that the coolant I'm using has a bit of a tendancy to foam, and that doesn't drain so well. I turned down the flow on my pump a bit and that took care of the problem for the most part. Speaking of which, the pump if from Harbor Freight, their P/N 45305.

I'm very pleased with the enclosure, and an unexpected benefit is that the 3/4" MDF really cuts down on the noise, which makes my wife happy! Most of the noise comes through the large front acrylic doors, but the ear protection knocks that down the rest of the way. Mainly it is nice that it keeps the noise polution out of the rest of the house.

I finished up the spindle pulley yesterday and will be working on the motor pulley today. I haven't test fitted the pulley yet, but if my calipers are accurate it should fit nicely!

BTW, the motor that I'm using is a 2.5 peak HP unit from Surplus Center. Two things: they don't sell the correct speed controller for it and, if you work it hard, it will need a fan.

All the DC speed controllers Surplus Center sells (currently) are of the SCR variety. This motor is PWM rated. Running it off a SCR controller will make it hot very fast, can fry the brushes and demagnetize the permant magnets. Unfortunately, about the only PWM drive I've found that is rated to run this cheeta of motors is the KBWT-112 from KB Electronics. It can be purchased through solidstatedrives.com. It ain't cheap. I'm getting away with running it on an SCR controller, but I've got a fan on it and try not to load it too hard. The motor has a thermal switch (which can be wired in series with the armature wires) which will open at about 100 degrees C. Having the motor abruptly shut down in the middle of a toolpath is frustrating, but the steppers will just get angry and it is better than smoking the motor. The KB drive is definitely in my near future.

Speaking of the fan, with just a little creativity this is an easy thing to accomplish. If you look closely at one of the pictures in the New Enclosure gallery at the right you'll see the fan... just look for the shiny propeller whizzing around at about 5000 RPM on top of the motor. It is a 1/2" wide, 1/8" thick piece of aluminum stock. I drilled a 9/32" hole at the exact center, put it in the bench vise and twisted a pitch on both sides. I pressed (lightly hammered) it onto the stubby shaft coming out the top of that motor and VIOLA! The motor now has a fan!

Ok, some might call that crazy to have an unshrouded "fan" whizzing around like that but keep in mind it is behind .220" thick acrylic. There's no way I'd try this trick if it were just out in the open. I've ran it for probably about an hour or two total now and it works great. The air inside the enclosure is noticably warm when I open the doors after a long milling job so it is definitely cooling the motor.

X1 Counterweight Installed

2006-03-02T16:53:00.002-05:00

The counterweight is installed! It was pretty easy as a novice such as myself did it in about an hour. I think the longest part of the project was going very slowly with my new tap and die set to make sure I didn't break anything.

X1 Mill Head Counterweight

2006-02-28T16:47:00.002-05:00

It is somewhat commonly accepted that the head of the Micro Mill needs to be counter weighted so that the Z-axis screw isn't doing all the "heavy lifting." One thing that I found interesting though is the amount of folks on the 'net that will simply quote a McMaster-Carr part number for a gas spring or state that they are using a pulley system of some kind. I have yet to find someone that backs up their counterweight system with some empirical research. Also, I've seen folks using gas springs that are significantly longer than the mill's Z-axis. What's that about? I've also seen some very elaborate mounting systems to compensate for "out of square mounting surfaces" and the like. There's basically some pretty poor engineering going on out there. Scratch that! Some of this stuff should just be common sense.

So that other folks can benefit from my research and draw their own conclusions rather than simply accept mine, here's my counterweight narrative:

I just took a rough measurement of the head weight. This method won't work for everyone, and the "why" will become evident quickly! In order to measure the head weight after it was mounted on my bench, I had to get creative. Yes, I could have just yanked the whole head off and placed it on a scale, but there are a few problems with that. First, it is awkward and hard to get an accurate measure on bathroom scale. Also, it has a light covering of oil on various surfaces and I hesitate to slime the scale. Most importantly, I'm lazy and would rather not have to try to remount the head after removing it!!

The solution was to start by locking down the Z-axis using the gib screw. I then unbolted the Z bearing block. After placing a bathroom scale on the floor, I had my wife climb on and I took the reading. Not everyone's wife would be that accepting as being used as an instrument of measure, but one uses the tools at his disposal! Kudos to my wife for being a good sport! Anyway, I unlocked the gib screw and, after making sure the head moved up and down freely, took another reading. We moved it a few times and took further readings just to verify. After some cowboy-style statistical sampling, I figured it was a good enough data set. I locked the gib screw and sent my wife off to wash her hands!

The total weight of the head is 19.5 lbs. Frankly, I was really hoping it would be closer to 25 lbs so that I could use a 30 lb gas spring and get 5 lbs of upward preload to deal with some of the lash in the Z screw. I think I'm going to go for the 20 lb gas spring, thereby achieving almost a neutral weight and deal with the backlash in a more appropriate fashion at a later date. But wait: "surely you can find a 25 lb spring" you say. And to that I would answer, "yes, I can" but more important than further pursuing this inappropriate backlash fix, I have other reason for choosing a 20 lb spring.

I'm sourcing the majority of the hardware for this project from McMaster-Carr. Mainly due to the fact my local hardware stores suck. The ones that are open past 5pm just don't have a good selection (and I refuse to shop somewhere that closes their doors before most folks get home from work). McMaster is also cheaper in many cases. They are also excellent folks to deal with, ship quickly and provide one stop hardware shopping. These and other reasons have directed me to choose to limit myself to their selection. Of the gas springs they offer, the smallest available in a 25 lb size is 18 inches long fully extended and over 10 inches compressed. Not a truly good fit for what I'm going to do with regards to mounting.

This brings me to another design upgrade this project offers. Without having the Z gib very tight, the front of the head sags slightly. Not ideal when trying to plunge and end mill or do precision boring. To help with this the ideal solution is to get the counterweight force as close to directly below the center of gravity as possible. Anyone know where that is? I can certainly tell you where it isn't! At the lead screw, screw bracket/nut, or gib! Right where most gas springs are mounted! This is where the folks using pulley systems really have the design advantage. They can choose a mount point in a number of locations. I would do a pulley system, but they look gangly. :-)

The final solution (all part numbers are from McMaster-Carr):

Part Number	Description
9416K171	20lb M6 threaded end gas spring
9416K74	(2) 10mm steel ball sockets for M6 threads
9512K73	(2) 10mm ball stud 5/16-18 threaded

The idea will be to drill and tap two 5/16-18 holes. One in the base casting and the other in the Z axis bracket/nut. Once it is mounted I'll post pictures for that part of the project.

Regarding the Z axis lash, I had a thought: I think I'll cut the Z "nut" horizontally and add a couple screws to space it away from the other half. That would serve the function of putting a bit of preload on the nut/screw assembly. I'll follow-up with details when/if I do this.

Oil Analysis for My Truck

2006-01-23T17:44:00.003-05:00

Before my extended warranty ran out I figured I'd get an oil analysis done to uncover any hidden problems. I bought a kit at a local auto parts store and, to my surprise, the analysis is actually done at a local company! Check out oil-lab.com for more details.

I received the analysis back only a few days after mailing it in and, low and behold, there was antifreeze in the oil. I wasn't entirely surprised as these engines are known to have lower intake manifold gasket leaks.

The part that surprised me was the willingness of the warranty company to fix the problem. I've heard horror stories about extended warranty places not wanting to fix anything unless there is a catastrophic failure of some kind. This was not the case! They were more than willing to fix the problem and actually complimented me on my proactive oil analysis!

To make a long story short, I took it to the local dealership and let them do the work. Should there be any problems I know they will take care of it long after the short-term extended warranty has expired.

I already have another analysis kit ready to do a follow-up check in a couple thousand miles. I'm hoping that truly solved the problem as I can't imagine what else could be leaking!!

New Truck, New Todo's

2005-12-04T17:46:00.003-05:00

A used vehicle combined with my intolerance for anything other than mechanical perfection leads to one thing: a maintenance fest! Unfortunately I didn't have this new site up while all this maintenance was going on. Had it been up the following would have been much more detailed, but this will at least bring us up to date:

The first thing I needed to do was install a car alarm and remote start. Rather than pay some chump to install one for me I got to thinking... I could install it myself. I'm quite qualified in electronics and automotive electrical, if I do say so myself. Besides, nobody is going to take the same care with my vehicle that I would. Then I started thinking some more... There are companies out there that sell pre-FCC-certified transmitter and receiver combinations. I could fab up my own system! I did some more research and found out, in this case, I could buy an adequate pre-fab system at a fraction of the cost it would take for me to create a one-off. I ended up buying a Viper 791XV online. The price was very right! At under $200, it was a fraction of retail and I didn't have to pay some installer to screw up the wiring. The installation was a piece of cake, but keep in mind this is coming from a guy who programs microcontrollers and designs printed circuit boards for fun. Anyway, it is working nicely and is a real treat on those cold morning!

One item down!

The next item I had to deal with was getting a topper (a.k.a cap, lid, etc.) for the truck. First, let me go on record as saying I think toppers make trucks look lame! Only members of the AARP need to own toppers! I do however have a dog and rather than be one of those red necks that (very dangerously) let their dog ride around in a uncovered bed, I opted for the AARP-endorsed option.

I wasn't about to spend $1000+ on a new topper. After all, this is a used truck! I found one that was nice enough on eBay. It was structurally sound and was of approximately the style I wanted. I bought it (for a steal) and took it to my body shop guy at Hills Body Shop in Howard City, MI. He squirted on a nice coat of paint and it matches the truck's paint quite well. I told him I really didn't need perfection (on this job) as it was a used topper and a used truck and the topper wasn't even going to be on it in the warm months (unless the dog goes for a ride). That's the other advantage of a topper - it keeps the salt and crud out of the bed and helps a little with corrosion prevention in the winter.

Two down!

The remaining significant item that needed to be dealt with was the ABS. At low speeds (< 5 MPH) the ABS would activate. It was very annoying but also would likely have evolved into an unsafe condition. It is a known issue with these trucks and has a very simple cure. The problem is caused by one or both of the front wheel speed sensors being pushed away from the tone ring by corrosion on the mounting surface. It is almost like moving a microphone further away from your mouth. When the vehicle slows down to a certain point, the ABS computer no longer sees a signal coming from that wheel and assumes it has locked up. It begins to pulse the hydraulics and the vehicle stops.

The fix was simply to pull the sensor out, plug the hole that goes into the wheel hub with a bit of paper towel, then polish the surface with sand paper or similar abrasive. I greased the mounting surfaces liberally with synthetic grease to repel water (and prevent corrosion) and mounted the sensor back in the hole. Viola! Problem solved. And ABS works great too. I've "used" it several times now that the snow has fallen and the truck stops straight and smooth.

All done! At least until spring...

There are a few other items that I want to do when it warms up. I purchased a rust counteracting paint that I want to treat the entire frame with as I plan on keeping this truck for a long time. I also want to replace the door hinge bushings (another known issue on these trucks) to deal with some door sag. Of course, there are plenty of other things I want to do, but now I think I'm just inventing things to keep me busy!

Retire the S-10

2005-10-03T17:48:00.001-04:00

I decided it was time to retire my 1993 S-10 Blazer. It had over 250,000 miles on it and was really showing its age. It was still a reasonably solid truck but I would have had to dump a considerable amount of money into it to make it worthy (by my standards) for continued duty. What it really came down to was after spending a ton of money on it I would still have a mini-SUV. Let's face it - every home owner with a little DIY in his blood needs a pick-up truck at one point or another. Not being the kind of person who likes to rely on friends to provide for my heavy-hauling needs, I decided it was time to go truck shopping!

After a brief (and somewhat lucky) search, I found a great truck at a little car dealership in Twin Lake, MI called MD Auto. Typical used car dealer but I certainly wouldn't call them sleazy. They met my two criteria: they had a vehicle I wanted and were willing to deal. And deal I did! When it was all said and done I was pretty pleased with the overall package.