Another Airgun Blog

"Fixing" the Sterling's Compression Tube

2012-02-01T20:22:00.000-08:00

Been ruminating about the transfer port in the Sterling for a few days now.

Those sharp-edges worried me. It looked like it could/would eat the new piston seal within a few shots. Thought about making an insert to fill in near the edge, but it seemed like difficult work considering it's so deep in the tube.

This 1" stainless steel washer should do the trick, but it's just a couple thousandths too large in diameter to fit into the compression tube.

Mounted it on a mandrel and touched the edge with a mill file. In about two seconds, it was sized.

The washer barely drops to the bottom of the tube. (OK, it's technically the front of the tube, but you get the idea.)

Washer is so thin so there won't be any appreciable change in compression stroke.

Used a good degreaser to thoroughly clean the inside of the tube.

Cut a piece of aluminum tube to fit inside the length of the tube when the end cap is threaded down.

The aluminum tube will push and hold the washer against the front of the tube as the J-B Weld epoxy sets up. There's really not another way to secure the washer in place--at least, none that I could envision.

Not using the quick-set version. Want the longer set-up time so I don't have to rush--as well as the higher strength.

A plastic spacer wrapped near the end of a 3/16" steel rod allowed me to get down to the bottom of the tube without the epoxy covered end touching the inside wall.

Washer dropped into place and the rod and end cap installed. I cleaned the excess epoxy from the transfer port and set it aside. I'll look at this again in about twenty-four hours. In the mean time, I'll clean the barrel and degrease the mainspring. The stock could probably stand another coat of oil, too.

Reassembly should happen in another day or two. Please check back. I hope it all works.

Repairing the Damaged Sterling Piston

2012-01-25T22:15:00.000-08:00

Slowly bringing the .20 caliber Sterling back to life.   Want to salvage the original damaged piston by reworking it to a different seal configuration. I don't see much point in using the spare undamaged piston, as the seals aren't just difficult to obtain--they're impossible. Couldn't warm up to that center-mounted rubber bumper, either.

Started by measuring the ID of the compression tube. It's essentially a 1" bore. Next, I went through my various seals.   The criteria: Obviously fit to the tube was foremost, followed by availability, and to some extent, design. I wanted the seal to have a relatively thick band near the edge for durability, as I'm concerned about the deep transfer port groove in the front of the Sterling's compression chamber. Lastly, the seal had to be readily adaptable to the damaged piston. Picked a spare seal I'd obtained from Crosman to fit my Remington Summit. It's Crosman's part # B18-04-1A. I think it was about $4. The piston seal requires a 60 degree (included) angle cone for attachment. I'll get to that a bit later.

The head of the piston is brazed into the front end of the tube. There's about half an inch of steel inside the tube, leaving lots of metal to work with.   Trued up the piston in a 4-jaw chuck on the Taig. There's too much overhang here...

Added the steady rest, and started cutting off the damaged grooves.

At the last moment, I elected to leave a shoulder on the front of the piston. Eventually, I turned this shoulder down to about 0.503" so a steel washer would press fit into place. Thought this would provide some sort of protection for the actual front of the piston body.

With the shoulder finished, I spotted for a hole with a center drill.

Through-drilled with a #20 bit.

Tapped the hole M5 x 0.8mm.

Broke the edge with a countersink to finish the piston head.

Now, I need a 60 degree cone to mount that seal to the front of the piston. Mounted the compound crosslide to the Taig set it to 30 degrees. I cut this taper on a scrap of aluminum rod then realized I was going the wrong direction. This would be too difficult to do additional machine work to the wide end of the cone...

Flipped the scrap in the jaws and readjusted the compound. We'll call it -30 degrees. Cut the cone in reverse. Remember that the larger end is the front...

Here's where I eyeball everything, I faced down the end until is was just fit into the piston seal.

Through drilled to clear the M5 screw.

Countersunk to match the angle of the M5 flat head. Cut until the head fit just below flush.

The rear of the seal has a 0.50" hole, so the rear of the cone must match that diameter.

A little layout fluid and some easy caliper work marked 0.500". Cut just to the line with a parting tool.

The piston, black steel washer, aluminum cone adapter, seal and bolt.

Couldn't have asked for a better fit.

Here it is above the spare stock piston. Getting close, but I'm not quite ready to put the gun back together yet.

Check back soon.

Benjamin Sterling HR-81 Fallback Plans A and B

2012-01-21T22:02:00.000-08:00

Not to be deterred by the defective compression tube on the Sterling, I went back up to Precision Airgun in Maple Heights, OH and showed the bad tube to Chuck. He had a couple more Sterlings still in inventory, but not another .20 cal. Neither of us wanted to cannibalize another gun just for the compression tube, though he seemed less concerned than me. He dug around for a few minutes and found a cutaway/demo HR-81. ???!!!! Who has this kind of stuff lying around?

The tube looks intact. It was obviously made to show the unique bolt loading design.

Made from early (pre-Benjamin marked) components. Maybe this was a way to use up some of the leftover British components.

Right side. This is the bolt loading trough. Note the line of brass at the brazed joint.

The cutaway on the left side shows a non-lead synthetic skirted pellet just forward of the air transfer port.

The bolt locked in the forward position has an o-ring to seal just behind the port.

Disassembled as in parts 1 and 2. The trigger housing was cut--probably to show sear engagement and trigger function. Certainly gave me a better understanding of their relationship.

After looking at it for a few minutes, I decided there just wasn't enough metal left in the housing to support the sear pivot pin. There were also some small dimensional differences at the front of the tube that would've made retrofitting more difficult. Reluctantly, I went back to see Chuck with the bad news.

He sent me off with another Sterling--this one in .22 cal--and told me to bring back whatever spare parts were left. There's probably not a single thing wrong with the Sterling in .22 cal, I just want a .20 for some reason. Certainly has something to do with losing two .20 cal rifles a few years ago--a Beeman R10 Deluxe and HW-77k. Replacing my youth.

Took this one apart a bit differently. This is a better method for the Sterling. After removing the rear sight, I pulled the cocking lever then unbolted the intact compression tube from the breech.

My spring compressor is cross drilled for 3/4" dowel rods so the bed can be shortened to any length necessary.

The was much easier than working around barreled action with that protruding globe front sight.

OK.... There was almost a second of consideration about using the piston from this gun to simply replace the smashed one from the first.

Except the crash bumper is already deformed. This is from sitting for years with spring pre-load. No, I didn't shoot the gun beforehand.

Lemme see if I can get the camera to cooperate.

Remnants of the bumper in the air transfer port groove at the front of the compression chamber. Which is nice.

Dug it out with a wooden matchstick.

So, the tube itself is a go, but the piston head design is a problem--at least in respect to sourcing replacement ring seals and perhaps also the design itself is flawed. Then again, the bumper material is twenty years old... Was the bumper found to be necessary or was it a design error? Certainly can't presume to know more than the engineers who designed the gun in the first place.

In considering how to remake the piston, I don't know if a parachute seal will fare any better against that groove in the front of the tube. Seems reasonable to start with the damaged piston and make it work with a readily available commercial seal. Maybe something with a sturdy looking edge, certainly the groove itself is the issue. Sorry, I'm just talking to myself here...

As always, more soon.

Benjamin Sterling HR-81 Tear Down Part 2

2012-01-18T07:21:00.000-08:00

With the piston looking like this after just a couple shots, I found myself...concerned. I'm not sure that's the correct word.

There are--or were--two black flat rubber seals with an o-ring underneath each. The pinkish center piece looks like simply a bumper to protect the face of the piston against contact with the front of the compression tube.

After digging the mess out, it looks like the bumper was glued in place.

Let's see what's going on.

There's a huge blob of excess brass in the end of the tube.

Huge amount of overfill from brazing the front of the compression tube cap to the body. Tube is shot. I kinda doubt Crosman has any of these compression tubes laying around. It's been probably twenty years since the gun was in production. For most of us, this would be the end of the project. I think I've got an ace in the hole this time around. More on that later.

There's absolutely no good reason to remove the compression tube for normal maintenance. So don't bother with the following step: The compression tube is affixed to the breech block with two socket head cap screws. A 3/16" allen wrench didn't have enough swing room.

The bolts were extremely tight. I didn't think they were coming out without heat, but a longer handle and additional pressure did the trick.

An o-ring seals the compression tube to the breech.

Might as well finish this. A small set screw retains the bolt handle.

Like everything else on this gun, it's SAE. I didn't measure it, but I think it's a #8-32.

I expected the bolt handle to pull out after removing the set screw, but it was threaded into the bolt probe and has to be unscrewed. The probe is pretty long, as is the spring behind it.

Next time around I'll see what I can do to source another compression tube. I'd rather not return the gun as I haven't seen another in .20 cal. I don't like the piston seal design so I may retrofit a parachute design seal.

We'll see what happens.

Benjamin Sterling HR-81 Tear Down Part 1

2012-01-14T14:48:00.000-08:00

Started to tear down the Sterling the other night. Technically, this is a Benjamin Sterling as it was made in Racine, WI. This gun is a .20 cal. And .20 cals are typically Sheridans, so shouldn't it be a Sheridan Sterling? I probably ask too many stupid questions.

Started by removing the two forward stock screws. Note, these are SAE fasteners--not metric as on the original British made Sterlings.

Removed the rearmost screw in the trigger guard and action lifted out of the stock.

Popped off the circlip on the rear sight elevation pivot.

Unscrewed the right side bolt and the sight and elevation spring came off from the base.

Two small screws and a recoil pin hold the sight base to the upper tube.

Just a pic of the holes in the tube.

As I had no idea how much preload was on the mainspring (--though I swear that several old sources reported that the preload was absolutely minimal) I threw it into the mainspring compressor. The brass drift is in the through hole in the end cap to act as a handle.

End cap was unscrewed and the spring pre-load backed off.

That's a good 3+ inches of pre-load on the spring. I sure wouldn't call that "minimal". I think we should add this gun to the list of "should use a spring compressor for disassembly/reassembly."

Thirteen and a half inches of spring. Shades of the Feinwerkbau 124.

This is quite possibly the longest factory spring guide I've ever seen. The steel guide is roll-pinned into the threaded end cap. Does anyone know if the British version has a threaded end cap or was this a tongue-in-cheek warning shot at the old Beeman "Tap the Cap" ad campaign?

There's another end cap on the upper tube. Double threaded end caps. It's like they're hitting Beeman with both barrels.

Threaded the mounting bolt into the bottom of the cap...

and unscrewed it from the tube.

Like so.

Couldn't get the pivot's lock bolt to move with a regular screwdriver. The small ratchet handle in the Chapman kit provided enough leverage.

After its removal, the main pivot bolt is unscrewed from the right side.

With the pivot bolt removed, the cocking lever can be pulled out enough to disengage from the piston.

Interesting. The compression tube is bolted to the breech block.

Pressed out the sear pivot with a brass drift.

The sear is now free to drop down enough to allow the piston to pass.

Piston didn't want to come out. Really tight.

Awesome. My brand new, old stock gun has a smashed piston.

Double ring seals with a center bumper.

It's cracked, too, just for good measure.

I'll assume that's why it didn't want to come out of the tube. I can probably salvage this a couple ways. But the pertinent question is why?

More soon.

Slavia 618 Re-tune

2012-01-09T13:54:00.001-08:00

Yes, it’s me. Sorry for the lack of postings lately but life has a way of getting busy when you have two jobs and two kids. Good thing Derrick is so prolific!
Back in September some friends came over to shoot airguns with their kids. The Slavia 618 (pt.1, pt.2) is a great size for a child but a few pellets into being shot it just refused to work. So I put it on the rework pile. I finally had a chance to take it apart. I expected there was a problem with the home made seal, but what I found was another issue.

The guts.

I think I can chalk this up to inexperience on my part. I clearly was a little heavy handed with the lube. The piston was gummed up in the cylinder and there was altogether too much heavy airgun grease.

I also decided it would be a good idea to smooth the piston where it makes contact with the bore.

Polished up on the beartex wheel.

I used moly sparingly on the contact surfaces and seal.

Derrick’s favorite, Slick Honey, is perfect for low power airguns. I put a thin smear on most of the other surfaces.

I was able to find my fancy spring end block insertion tool. Not bad considering I last worked on this in 2008.

Just a twist to get it to catch.

I replaced the heavy, slightly too large trigger spring with a much lighter spring. Not sure if it make a difference.

Back together and it’s back to a functioning state. I’ll probably find that most of the first airguns I worked on have too much lube…live and learn.

New Muzzle Brake on the FWB 124--Final

2012-01-08T12:04:00.000-08:00

A little scotchbrite on the brake gave it a good enough finish for now. I was going to blue it, but after looking at the various airguns, I decided to install it on the old two-tone FWB 124 as is. If it ends up finding a permanent home here, I'll run it down to Akron Plating and let them give it a coat of hard chrome to better match the compression tube.

It's hard to take a decent pic of rifles that are over 40" long and have them show up well on the blog.

The brake matches the hard chrome fairly well. I've given it a coat of wax to prevent corrosion.

The trim size works well with the slenderness of the stock.

The setscrews are dead flush when tightened.

Think I may be overhauling the Sterling next time around. I've got several other project guns here including both a Rochester and old Benjamin pumper in many pieces. Also, just picked up an unfinished walnut stock inlet for a Crosman 160. There's lots of possibilities. Nick should be back with a project soon.

Check back.

Fill Plug for the Hand Pump

2012-01-01T18:17:00.000-08:00

This was super quick and dirty. Threw this together while working on the muzzle brake. Wanted a plug to fit in the female foster fitting on the end of my Benjamin hand pump. It's really just to keep the fitting clean of dust, dirt, debris while the pump is in the basement or while traveling.

A spare male foster fitting was used to supply some basic dimensions. Chopped off a small piece of acetal rod.

Faced the acetal in the Taig and added a small bevel.

Cut a couple grooves for o-rings. This is all just quick freehand so far.

Need to get the other end to about this diameter.

A really small homemade parting tool did the trick.

A few comparisons to the foster part showed where to make some additional relief cuts.

Two green o-rings will help me find the plug when I set it down on a dark floor.

About ten minutes later--and it even fits.

A New Muzzle Brake--Part 2

2012-01-01T10:48:00.000-08:00

Happy 2012 from Another Airgun Blog!

Still working on the muzzle brake. I flipped the brake around and milled the back end square.

Off on a quick tool tangent: Turned an indicator holder from a piece of 5/16" key stock. It fits in a spare tool post holder.

This is mounted to the headstock in one of the various t-nut channels, either on top, or on the back.

After adjusting the runout, I got out the compound crosslide. (It's on the right)

I'm sure we've shown this before, but the compound mounts to the top of the crosslide and allows the cutter to travel at an angle respective to the work.

With a steady rest mounted to help prevent deflection, many light passes cut the taper.

Then back to the mill for a couple mounting screws. A couple pieces cut from a target protect the workpiece. Spotting for the hole here.

Through drilling.

Tapping M4 x 0.7mm.

Snugged a handle around the body of the tap. The tap itself is barely held in the Jacob's chuck for alignment.

Mentioned about a month ago about needing some new countersinks. Over the course of a couple weeks, I replaced everything I had and then some. I've found that gun shows are often excellent hunting grounds for machine tools at low prices. Now, when I need a countersink, I feel like Rodney Dangerfield in the pro shop in Caddy Shack. Hey! I'll take one of these, two of those...

Used a 90 degree single flute cutter to chamfer the edge of the hole.

Still need to finalize what to put this on and make sure it fits then get a finish on it.

More soon.

Drilling More Holes!-- A New Muzzle Brake--Part 1

2011-12-30T21:20:00.000-08:00

Still playing with the spin index. From the first time I saw one, I thought it would be the perfect "muzzle brake making device". And why not? The spin index allows for precise rotation of the work for drilling or milling. Well, I've got to make one just for the cheap thrills from another piece of 0.875" DOM tubing. No particular gun in mind for this at the moment. Rather foolhardy, as the ID of the tube is around 0.635"--about 16mm, so it won't fit many rifles without reducing shims.

Faced the end of the tube off.

Did some layout and marked off 0.375" intervals.

Squinting makes all my projects look better.

Located center.

Picked a short and stout drill bit as I don't want to spot each hole. I believe this is a letter N. The diameter wasn't critical. What was critical was having enough rigidity in the bit that there was no wandering while drilling through both walls.

Staggered the holes.

Wanted a bit more aggressive look to it, so I milled off the end, cutting halfway through the outermost ring of holes.

It'll need tapered--as well as a couple threaded holes for set screws. Hmmmmmm...I suppose this will fit the R1 or Marksman Mod. 56 FTS. I'll find something.

Check back soon.

Derrick drills a hole! IZH 53M

2011-12-21T08:31:00.001-08:00

I came back to the IZH 53M after seeing Tom Gaylord review the pistol on the Pyramyd Airgun blog.

Wanted to add a hole in the frame to gain access to the trigger adjusting screw. The first versions of the gun had an access hole.

But now, not all versions of the 53M even have this trigger screw. Apparently, this has been omitted in the most recent iteration. Mine is sort of a transition gun--it has the screw, but you have to remove the action from the stock to gain access. Annoying, though once you nail the adjustment, I suppose that's it.

Removed the three stock screws. The red vinyl tape marks the angle of the adjustment screw.

This is the screwdriver I'll probably use. The shank is only 3/32 (0.0938") in diameter. I went through the drill bits and settled on a #39 bit--about a 0.0995".

Padded out the vise with rubber jaws.

Magnets hold the jaws in place.

Also wrapped some masking tape around the grip frame. Eyeballed the drill bit to the red tape until they looked parallel.

When the gun was still assembled, I'd marked the frame at what looked like the right spot.

Deburred the hole by hand with a small countersink. Just broke the corner.

Not exactly perfect, but it works. Not too bad for a five minute project.

Hopefully something better next time around. As always, check back in a few days.

Quick Look at a Benjamin Sterling HR81

2011-12-13T19:20:00.000-08:00

Nick is a busy guy right now so you're still stuck with me. I haven't got anything in the works right now, but thought I'd share a birthday purchase I made a few days ago. It was still new in the box--a Benjamin/Sterling HR81 in .20 cal.

This gun was made in Racine, Wisconsin. The barrels were reported to be made by Lothar Walther--at least in the few reports on the guns that I can find. If that's true, then the barrel should be choked. Age? Well, the model 81 was dropped from production around 1994, so this certainly can't be any newer.

The metal polish is excellent--actually better than current Weihrauch production. Metal finish is almost black like an Air Arms. Hey, don't shoot the messenger.

Tunnel front sight. It came with a couple different inserts including a target globe.

Stock is American black walnut. It's got some figure. The oil finish looks like a simple coat of linseed. It's a good look. There was also a higher-end model the HR83 that had a pronounced cheek piece, Williams peep rear sight and hand cut checkering. I'll eventually come up to speed with the checkering tools for this stock.

Forend is a bit abrupt. Almost like they didn't know what to do with the lines of the stock. Rounder, fuller, schnabeled--almost anything would've looked better.

Pellet is loaded in a trough--it's genius. Fingers are never in danger of a bear trap accident.

The bolt is spring loaded and takes some pressure to close. The rear sight is an exceedingly simple open notch. It's almost out of place compared to the front sight. The stamped sheet steel trigger guard also detracts given the metal finish and walnut.

The small amount of mainspring I can see show it to be pretty dry. I was told upon purchase, that the gun should be re-lubed. As old as the gun is, I'd say that's sage advice.

Unsure exactly how soon I can start tearing into this one, but it's probably next up.

Our friend, Tom Gaylord started to review one of these guns on the Pyramyd Air Blog. His write-ups are here.

Please check back soon.

Heavy Barrel Sleeve for a BAM B26-2 Part 3 Final

2011-12-07T15:27:00.001-08:00

Quick note: As you've noticed, Nick hasn't been posting much of late. He and Felice are a bit hectic these days making, selling, and shipping jewelry to all parts of the globe. Click here and give them some support and get something handcrafted for your wife/sister/girlfriend. My wife has several pieces of Felice's jewelry and says they're worth much more than the asking price. The garden vases are especially elegant if you can't pick jewelry and know someone who spends time working in the yard. Yeah, it's a plug, but it's really beautiful--and affordable--stuff. Please consider giving them an order if you're able. They'll appreciate it and you'll have something uniquely made by human hands.

OK, the barrel shroud. Yep... I blued it with Van's cold blue and it was a rather dark gray color and doesn't quite match the metalwork on the B26-2. Don't think the issue is the Van's so much as just each cold blue giving a different result with each alloy. It was completely uniform in color. IN an attempt to get it both blacker and a bit more "steel blue", I burnished some Birchwood Casey Permablue paste into the piece. This colored it almost exactly as below. After drying the piece, I wiped it down again with another coat of Van's on a gray Scotchbrite pad. Again, it was blended seamlessly. Next, I rinsed the shroud in cold, then hot water.

Once dry, it was slathered with Rig grease. Rig grease came out on top of Brownell's corrosion protection test a few years ago. I coat all the metalwork on my airguns with it.

The sleeve--after fluting--weighs in at just over 12 oz. Three quarters of a pound.

After installation, point of impact changed roughly 0.750" low at 33 feet.

The gun is noticeably muzzle heavy and I like it.

Not sure what's next. But check back soon.

Heavy Barrel Sleeve for a BAM B26-2 Part 2

2011-12-03T20:51:00.001-08:00

Couldn't leave well enough alone with the shroud--and I guess I wanted some kind of redemption for screwing up the breech project.

Found a suitable ball nose milling cutter--it's a pretty large one at 7/8". The collet next to it is an R8 type. R8 collets are normally used to hold tooling.

Another type of collet--a 5C size--fits in a work positioning fixture called a spin index. Nick sent the index along with a machinist tooling kit-in-a-box gift pack when I bought the mill. Finding a box from Nick at the mailbox is always a treat--and a spin index was on my short list. Work can be rotated and positioned in increments as fine as one degree. Looks like the ticket for making ported muzzle brakes on a mill or drill press.

OK so an appropriately sized collet is installed in the index, then the work is installed into the collet. What's a collet? It's a slotted tube that grips around the work and squeezes inward--closing the collet--as the collet is tightened to the tool. They have tremendous gripping power but a rather small range of useability. I think the 5C's only collapse about 1/64" or so.

Due to the length of the shroud, the spin index by itself won't be sufficient to hold the piece for milling. The plan was to not actually anchor the indexer, but to set the work across the vise jaws and clamp the work in the vise to make a cut. After making the cut, the jaws are opened and the piece is indexed to the next location, vise is clamped and another cut is made.... I want to mill six flutes, so I'll rotate the shroud 60 degrees after each cut.

...If I ever get that far. The work is too low in the vise jaws.

A couple 1-2-3 blocks underneath the index gave the height required. I'll skip pictures of the mind numbing work to get the vise correctly aligned .

A bit ahead of myself, but the 7/8" ball mill was chucked and the head positioned. The quill was brought down until the tip of the cutter just made contact.

The mill has a digital readout for the spindle depth. This was set at zero.

Backed off the table and lowered the quill and visually looked at how deep I wanted the cut.

Noted the reading. This is the mill to depth.

To make sure the shroud is positioned to the same left/right location each time it's indexed, I made a work stop from an insert vise and a piece of square stock. When the end of the shroud touches against it, I know it's in the same location as before.

Next, adjusted the table travel stops. This will ensure the slots are all the same length.

Took a couple passes and worked my way down.

Rotated, and did it again.

And again...

And again... Eventually, I had six flutes.

Need to add some set screws to attach the shroud to the barrel. Rotated the work 30 degrees and lined up on a rib. Switched from the ball mill to a drill chuck. Spotted for the hole with a center drill.

Drilled through one wall with a #30 bit.

Followed by a piloted tap. The chuck holds the base of the tap handle perpendicular to the work and the tap handle is manually turned to cut the thread.

Used an M4 x 0.7mm tap. As is my norm, when the gun is metric, the accessory fasteners are metric. When the gun is Imperial...you get the idea. Did this two more times.

Deburred the inside of the shroud. The set screws need trimmed to length and the shroud needs a finish.

More soon.

Heavy Barrel Sleeve for a BAM B26-2 Part 1

2011-12-01T19:10:00.001-08:00

I've had a piece of steel for this project on hand for some time now.
Not sure as of yet just how far I'll go with it--more on that later.

The old .22 cal BAM B26-2 from a Pyramyd Air open house several years ago.

Aside from maybe needing a new blue job, there was nothing particularly wrong with the existing muzzle brake, just wanted something different.

Removed

Barrel band for the sling, too.

Gonna start with a 7/8" OD DOM (Drawn Over Mandrel) steel tube. The ID is 0.635".

Bought it because it's virtually a perfect fit over the barrel.

Should've bought an even longer tube, though I'd like it to eventually be the same length as the barrel.

I realized that it was slightly too large in diameter at the breech block and would need to be tapered.

Except the tube is longer than the bed of the Taig lathe.

Here's where another inch of length would've helped. I have about half an inch to chuck. I'm going to cut the taper just in front of the 3-jaw chuck. I set a carriage stop as well as set the compound crosslide at the very end of it's travel. Critical to check clearances to avoid running into the headstock. Could've easily used a mandrel inside the tube, but I saw that this would work--just barely.

Light cuts--necessary anyway when cutting a taper.

Ground a round-tipped tool bit. Played with the edge geometry a bit.

The steady rest fingers were greased with moly to help avoid scoring the tube. Just don't run them dry.

Don't try this at home. Wiped a file across the taper to blend it in. Next to the spinning 3-jaw, this is horrible idea. Seriously, don't do this.

This is also a bad idea--remember, there's very little material chucked in the jaws.

A quick shine with some 220 grit. Note the lathe bed is protected with foil from the grit.

Low speed and I kept the work supported. Un-chucked and cut the stub off the end.

Since it's too long to face down in the lathe, I cut the tapered end off squre using the mill.

Test fit.

Barely too long at the business end--and a bit uneven.

About 0.124" too long. Could've used that in the chuck...

Scratched a line in the layout blue. Just provides a witness line to cut to.

Touched the cutter to the end of the work then dialed in 0.118" into the table and made the cut. Switched to a higher speed and made a couple more passes taking off a couple thousandths each time until I hit the line.

I could just drill and tap for a few set screws, blue it and it's done. Or maybe I'll lose my mind and try fluting it. I'll try some test cuts on another piece of steel and see what kind of finish I can get.

More soon.

Crosman Breech Attempt--DOA

2011-11-30T19:51:00.001-08:00

Update.

Well, it was bound to happen sooner or later--abject project failure. The breech hit the recycling bin a few minutes ago. I found it impossible to use the small drill press and keep the bit on center when drilling for the barrel. There's no current plan to make a second attempt. Sorry 'bout that. I was really looking forward to this one. I'll have to regroup and come up with another project.

Crosman Breech Attempt-- Part 1

2011-11-24T05:48:00.001-08:00

Happy Thanksgiving to all our readers!

A few weeks ago, I bought a small milling machine from Grizzly. It somehow seems only fitting that the first real project would be a breech for a 22XX. And since I have almost no milling experience, this will probably be a complete and utter disaster. This whole project may end up in the recycle bin.

Bought a bar of 12L14 from Speedy Metals on my last order. It's 3/4" x 1" x 6". Took a clean up pass on one of the 3/4" sides with an endmill.

With the piece on parallels and cleaned up the opposite side. This makes the two sides parallel to each other. Vise parallels are simply pieces of thin metal that are precisely ground top and bottom that sit on the bed (bottom) of the vise so the top of the work sits above the jaws. If the work is really thin, just use a single parallel.

Wanted to try something different on the sides, so I used a flycutter. The flycutter can sweep a larger surface than an endmill in a single pass, so it's good for cleaning up large surfaces--though it's not as accurate.

Flipped the piece and did the opposite side.

Need to drill for the barrel and bolt. Drilling a six inch deep hole in a piece of steel is not an easy task. The new mill doesn't have enough vertical travel to accommodate the vise, workpiece and 6"+ drill bit. The Taig lathe doesn't have enough bed length, either. Hmmmm... Guess I need a full size drill press after all. Since I didn't want to buy one at 9 PM last night, that left the small bench top drill press. I swung the table out of the way and used the base. The base on this machine has slots to fix workpieces. For the size and low cost of this drill press, it's pretty well thought out. I used a 3" drill press vise that is ground on the bottom and both sides. The vise was mounted sideways and clamped down with step blocks, t-nuts and strap clamps. Getting the fixture right took some time. Found hole center with a pointed indicator in the chuck.

Started drilling with a 1/4" standard length drill bit.

After drilling into the work approx two inches, I removed the bit and the workpiece then inserted a longer bit into the drilled hole. The work was reinstalled into the vise and the drill bit chucked and I continued drilling. After drilling over halfway through, I turned the work 180 degrees in the vise and drilled from the opposite end. With some luck, the holes met halfway and lined up quite well. Ran a 0.250" reamer through the length of the hole to clean it up.

Slid a piece of 0.250 drill rod through the hole and noted that the hole wasn't completely straight through the steel. Not unexpected, since it's almost impossible to keep a long drill bit from wandering as it cuts. It was very slightly angled side to side--which means the barrel will be pointed left or right depending on which end becomes the front. Had the angle been in the vertical plane, it would have been easy to fix when milling the bottom radius to fit against the gas tube. As I still need to drill for the barrel diameter, it seemed that I should fix this now. It made sense to use the hole itself as the reference point and just make the outside of the breech parallel to the drill rod.

Probably a lot of ways to do this, but I have a nice set of gauge blocks and I'd like to put them to work.

The gauge blocks are very precisely graduated lengths of steel. They can be combined to make exact lengths for layout, measurement...

I stacked four together on one end. I lifted the work just off the parallels and hung the piece by the drill rod.

Could have duplicated the stack height with the gauge blocks for the other side, but I grabbed an adjustable parallel instead. With a caliper locked open at the exact measurement of the gauge block stack, I matched the parallel to the exact size of the stacked blocks.

Slid the parallel under the other side. With the work hanging from the drill rod, I clamped down the vise.

Top of the workpiece just barely clears the top of the jaws.

Could've used the flycutter again, but this time I milled the top surface--just kissed it until the entire surface had material removed. The top is now parallel to the center hole. I turned the work over and seated that freshly cut face against the parallels in the vise and took another cut. Now both sides are parallel to the center drilled hole.

Lot more to do. Check back in a couple days.

Aeron Bulk-Fill Thread Cover Version 2.0

2011-11-20T14:21:00.001-08:00

Since I was already making a cap for one Aeron, I decided to make another for the second gun. I'm just going to pick up where I made some departures from the first.

Had a piece of knurled stainless steel. I think Nick set it in a care package a couple years ago. Drilled it out with a 5/16" bit. A piece of black plastic is behind it as a backer.

Drilled a hole in the bottom of the end cap with a #29 bit.

Tapped M5 x 0.8mm. Since it's going on a metric threaded gun...

Flipped the cap and took a clean up pass.

With a small boring bar, I cut a recess in the face for the knurled stainless disc.

Faced off a piece of 0.250" brass rod.

Spotted--

--then drilled a small hole in the center. I think I used a 3mm bit.

Turned the end of an M5 stainless bolt down to--hmmm--about 3mm.

Flipped the bolt and turned the head down to 0.315"--a couple thousandths over the 5/16" hole drilled through the piece of knurled stainless. I seem to be missing a pic. I pressed the ring and bolt together with some Loctite 680 and let it set up for 12 or so hours. Should be permanent.

Found the bottom of the bore inside the cap and drilled a gas vent hole. The hole cuts a half-round groove in the bottom.

Finished the cap in black. There's the press-fit ring and bolt. The brass tip was cut to size. It's a running fit (rotates freely on the end of the bolt).

Assembled. The idea is that turning the knurled ring should depress the pin in the end of the Aeron bulk-fill adapter and vent the gun. There have been a few times when it would have been advantageous if the gun could be emptied in a couple seconds rather than having to shoot the gun dry.

Getting a bit long. Ah well, it can go into the tool bin if I change my mind.

More soon.

Aeron Pistol Bulk-Fill Thread Cover

2011-11-13T20:29:00.001-08:00

One of my Aeron pistols was missing the cover that fits over the male bulk-fill threads at the bottom of the grip. The factory supplies a press-fit plastic cap. While it works fine, I need/want a second thread cover. The bulk-fill thread on the Czech pistols is M18 x 2mm. It took a couple weeks to track down a bottoming tap that didn't turn this into a $30 project.

Nick recently sent some 1" aluminum hex stock that had been languishing in his carport for years. Soon as I saw it, I knew it would be perfect for this. Chopped about a 3" length off to start.

As is the norm, the end was faced off square. A really sharp bit with some negative top rake and a high turning speed gave a dead flat surface in a single pass. Some cutting fluid didn't hurt either.

Rather than drill a hole first, I just plunged the boring bar into the aluminum face to start the hole. Took a few minutes, but I was able to bring the hole to approx 24mm deep, then bore the diameter to 16mm. Note: Not all boring bars work for this type of cut.

With a M18 x 2mm bottoming tap I was able to start the first couple threads by hand turning the headstock and feeding the tap gently until it started cutting. Once the tap starts cutting thread, it pulls itself into the work as long as the quill on the tail stock is free to move.

Transferred the work to the vise and switched to a larger tap handle.

About that much. Oh, I'd like to also recess the e-clip above the thread.

Finding the bottom of the hole.

Cut it beyond the rod and all will be OK.

The parting tool loves aluminum.

Chucked the cut off piece of work and cleaned up some corners, cut some decorative bevels...

With the boring bar, I cut a relief at the top of the thread to clear the e-clip.

Ran a piece of Scotchbrite over it to get a matte finish. I could definitely use a second one for the other pistol. Beats the pants off the plastic cover.

Inside view of the M18 x 2mm threads as well as the cut for the e-clip.

When (if) I make another, it'll probably have to be blackened.

More soon.

IZH 53M -- Finishing the End Cap and Reassembly

2011-11-11T22:22:00.000-08:00

Where was I? Oh, yes. Finishing the longest IZH 53M rebuild in recent history. I'll put a post together to show what I've been distracted on soon.

With the new end cap essentially shaped, I needed a way to both secure the cap to the compression tube and fix the spring guide in place. Did some layout and marked the location of the 6mm retaining pin hole from the gun. Centered in a v-block.

Through drilled.

Tapped M4 x .7mm.

Finished by hand.

Obviously, the M4 thread size is smaller in diameter than the factory 6mm end cap retaining pin. The plan is to recess the M4 bolt and put the load path into the head of the fastener rather than into the threading. Looking at various tools on hand and options, it made the most sense to resize the M4 screw heads slightly. First, though, I needed to make a quick holder. Cut and faced a scrap of 0.500" diam. aluminum rod.

Then spotted and drilled.

And tapped M4 to hold the bolts for machining.

Turned the M4 bolt heads down slightly to 0.245". This only removed a couple thousandths.

Next, I opened up the retaining pin hole in the compression tube to 0.250" Considering the hole was already 6mm, this is only an increase to about 6.35mm. Not much.

Test fit. Holes line up and the cap is bottomed against the tube. Almost there.

As it sits now, the shear force from the spring pressure will load the M4 threads.

Need to counterbore the cap on each side for the heads.

Used the compression tube as a guide. Some v-blocks and step clamps to hold it in location.

Had to make a bottoming drill bit first, but it worked.

Another test fit. Note how much deeper the head sits now.

Cleaning up the end of the cap.

Beveled the edge. Nothing fancy.

A few coats of Van's Cold Blue. This is hands down the very best cold blue I've ever used. Found a suitable rotation washer for the end of the mainspring to bear.

Goes like so.

Final test fit.

Almost no protrusion. Looks clean.

Cleaned up the cocking slot with a deburring tool. Took a couple seconds.

And then put moly grease on all the moving stuff.

Reassembly is just a reversal of Part 1.

A transfer punch worked as a slave pin to hold the cocking link together as I seated the pin.

Before installing the spring and endcap, the rear sight had to be slid onto the dovetails. I have a couple other sights that I may try on the pistol in the future. Each are a bit more substantial, but neither has a notch wide enough for a pistol and will need modification.

My first replacement spring candidate didn't make the final cut. Too stiff. Too hard to cock. Too much stress on the synthetic breech. Found another spring just like the original in my giant spring box.

Pressed the cap into place and secured the screws on each side.

Reinstalled the action into the grip frame.

Much better firing characteristics. Considering how devoid the gun was of lube, the moly alone probably made a big difference. The spring guide will doubtless add life to the mainspring.

You can just see the unreachable trigger adjustment screw. Think I need to drill an access hole in the grip frame.

More soon.

Healthways Plainsman BB Pistol Disassembly, Part 3

2011-11-08T16:45:00.000-08:00

Almost done…

The barrel end of the feed mechanism.

The BB hopper side of the feed mechanism.

The valve assembly is just pushed into the CO2 tube.
The cartridge is pierced and fills this chamber with gas. The o-ring was hard, it’s amazing that it was holding gas at all.

A snap ring holds the exhaust valve in the body.

Ok, a snap ring and a spring star washer holds the exhaust valve in the body.

I had to gently lever out the spring washer. The disk with the 4 holes allows the gas to flow.

Valve assembly.

For some reason the stem has a ground bevel on the end. Since there’s nothing to hold it in a particular orientation (unless it’s carefully aligned at the factory and then stays put?) I don’t see why.
I’m assuming that the rim of the seal holds the valve seal in?

I can’t tell if the stem is soldered, screwed or pressed in. No hint from the spring end. This is odd as the rest of the pistol is so repairable. But making a new valve stem would be easy I suppose. The pin diameter is the same as the Crosman guns from the era, but the seal is more like a Benjamin or Sheridan. I'll reuse it and if it leaks then I'll worry about making a replacement.

A standard sealing lip inside.

The cutouts in the valve body allow gas to flow around the end of the CO2 cartridge and into the valve.

The piercing assembly. Clip was levered out with a stout dental pick.

The piercing pin was pushed out from the other side (I opened the lever and wedged the pick up and into the hole.

An o-ring seals the pin.

It fits in this cup that looks to be staked in place. Yes, I put those two scratches at 12:00 on it. Oh well. It doesn’t matter.

I decided not to punch the lever pin out. those three notches means that it’s a press fit and has cut into the hole material. Better to leave it and not risk loosening the pin. The o-ring around the body (on the left) was hard as a rock.

A setscrew underneath the muzzle end of the frame.

Removed and a bushing for the barrel slips out.
So overall this was a unique design. I love design from this die cast era. Compared to the Roger or other die cast pistols, this has superior quality.

I’ll need to get some more 8 gram cartridges (I used up all I had with the Benjamin 30/30 debacle) to test after I get it back together.

Healthways Plainsman BB Pistol Disassembly, Part 2

2011-11-07T16:25:00.000-08:00

On I go…

The power adjuster and spring that connects to the hammer.

The power adjuster has three discrete notches around the periphery.

Which mate with the molded pin sticking out of the channel.

The CO2 cartridge chamber and valve assembly.

Notice the flat face of the exhaust valve.

The flat face sits against the o-ring and gas travels through.

What the heck, let’s call this a sear.

Just a flat bar with a dogleg.

Notice the spring on the hammer passes above the pin in the BB feed mechanism in front and below in the back (relative to the orientation of the pin…)

When the trigger is pulled it move the feed mechanism up.

The trigger and spring.

The hammer.

It has a steel insert.

A large nut for the piercing cap sits in the frame casting.

Right frame has three screws that are removed.

And the BB feed mechanism comes free.

Huh, a flat rubber gasket.

It was glued (probably with rubber cement of some sort) to the frame.

This is another first, the passage for the gas as it travels from the valve to the barrel is open on the side. The gasket seals it against the frame.

The barrel slides out. The barrel seems to be copper tubing but I suppose it could be bronze.
More to come…

Healthways Plainsman BB Pistol Disassembly, Part 1

2011-11-06T16:49:00.000-08:00

I picked this up awhile back and forgot I had it! It’s an early Healthways Plainsman BB pistol. The CO2Airguns site has a great write-up about it with links to a few other articles on the pistol.

Sort of like a Colt Woodsman, somewhat like a Nambu… It’s not ugly, just oddly proportioned.

”Plainsman .175”, “PAT. PEND.”, “Healthways L.A. CALIF”.

The other side.

The rear sight doubles as the BB filling gate.

Well it’ll be hard to spill BBs, unlike other guns.

The lever actuated piercing cap. The screw head is for power adjustment.

Unscrewed.

The CO2 cartridge is inserted neck down and the lever actuates that piercing pin.

It uses 8g. CO2 cartridges.

The left grip removed.

Removing the right grip.

Right grip removed.

More valve elements down in the tube.

Removing the left frame screws.

Five screws of two different lengths.

Nothing flew apart when I removed the left frame side although the loading gate spring did come out.

A fairly simple mechanism. Which is good.

The spring should be under the post extending from the loading gate.

I find it interesting that they used a straight piece of spring wire both here and as shown below with the safety. I haven’t seen this type of spring in any other airgun.

The safety is captured by a piece of straight spring wire that passes through a hole in the post. Notice the semicircular slot.
More to come…

Overhauling the IZH 53M -- Part 2

2011-11-02T21:58:00.000-07:00

Getting back to the IZH 53M after a short hiatus...

The steel came in replace the plastic factory end cap with something a bit more substantial. Before turning the piece, I installed some beater jaws into the scrolling chuck and trued them up with a small boring bar.

Sidetrack: Also made some extra vise jaws for the Wilton, too, since I was working on tools, with tools. Absolutely nothing to do with this post--but they're nice.

And definitely better than what came with the vise.

OK. Yes, end caps. The factory cap is plastic and, well, it's plastic... I cock the gun, point it at the target and I'm staring at this piece of black plastic that the mainspring is bearing directly against. Pointed at my eye. I know it's fine and it's not going to break. But still...

FrankB has me working in analog with this mic. The end cap is 0.923" on the slip fit into the tube. That'll be close enough.

Chucked a piece of 1.125" OD free machining steel...

...and quickly brought it to size. Removing the crosslide allowed me to test fit the compression tube to the cap without changing the set up.

Spotted with a center drill.

Gradually drilled a 0.500" counterbore. That's a lot of steel shavings.

Switched tool holders and used another boring bar to cut a stepped counterbore for the end of the mainspring.

The other day, I went through the extra mainsprings on hand and found a likely replacement; the original was slightly canted.

This is how it fits.

Need a spring guide to prevent the replacement spring from buckling. The blue plastic piece came from the scrap box--it's part of an old spring guide from a Rock Shox mountain bike fork. It's just slightly over 0.500" diameter. Saved it for exactly this kind of project.

Chopped off the flanged end and set up a dead center to prevent the rod from flexing away from the cut.

This will be the cap end.

Taking this down until it press fits into the cap.

Once it fit into the counterbore of the end cap, it was pressed in and the cap was chucked.

A few thousandths went away in a couple light passes. When the spring slid over the guide without binding, it was good. Had this been a high velocity spring rifle, a tighter fit would be useful to quell vibration.

Rounded the end freehand in the lathe with a file.

The gray smudges on the guide is moly grease transferred from the spring. I'll probably add a rotation washer, figure out how to secure the cap to the tube (and the guide to the cap) then shape the rear of the cap and blue it.

Should finish it up in another day or two. Check back soon.

RWS (Diana) Model 45 Notes.

2011-10-29T17:29:00.000-07:00

Just a few notes about putting the rifle back together.

I polished that rusty washer. Reassembly was largely the same as disassembly in reverse except as shown below. I lightly lubed everything and smeared a little silicone oil into the leather piston seal to get it to swell a little.

First try at reassembly. Ok, this was maybe the fifth time as I had longer pins, had a pin in the other slot, etc. in various permutations.

A slave pin is inserted in the springy part of the safety. This keeps it spread open so I can push the retaining pins through.

Back together with one pin in place.

But the slave pin was impossible to align with the hole. So I looked at the exploded view some more and figured that maybe I had the spring clip upside down – so I put it together as shown. At some point before this I did manage to get it together but the safety was stuck and wouldn’t move.

I also put the slave pin in the forward detent position (which would be “fire” rather than the rear detent position (“safe”).

Punching out the slave pin with the retention pin. Yay. I probably re- and dis-assembled it 20 times figuring this out.

A short slave pin for the trigger – the pin that holds it to the stock has to pass through and this helps.

The pin in place.

Note that the plastic caps for the pins are different on the Original 45 I showed earlier on the blog. These are countersunk with the flange outside. The caps on the RWS have the flange side in. I have no idea why.

The rifle together I turned my attention to the scope mount.

Pushing off the dovetail clamp.

A broken screw, a spring and lots of dried lacquer.

The pieces.

I was able to unscrew the screw holding it with pliers. Finally something easy.

Some new clamp screws fitted.

I punched the location of the scope stop screws. The setscrews are pointy (dog point). So I figured I’d replace them with cup point screws.

Made the punch mark slightly larger.

Spot drilled.

I then drilled shallow holes the diameter of the setscrews. They should sit in the holes and not move. The dog point screws did nothing to keep the scope mount from shifting. You can see evidence of screw marks on the rear of the scope rail.

All done. I shot a little and the velocity is the same (about 730fps) as it was before. So no improvement. I could probably soup it up by replacing the spring or fitting a synthetic seal but why bother? It’s peppy enough. I am wondering if I should have replaced the breech seal though. Maybe soon.