Wednesday, March 24, 2010

A New Crosman 22XX--Breech Cap and Cocking Pin

Still (slowly) working away at all the bits and pieces to finish this 2250 pistol.

Needed an end cap for the steel breech. Not sure how exactly I ended up with a Crosman steel breech missing all the assorted bits and pieces...Anyway, I began with a short length of 0.500" diameter drill rod.

Turned the end down to about a quarter inch to fit into the end of the breech.

A Crosman breech plug served as a model.

It's too long because I needed something to hold in the chuck.

Cut the excess off.

Just free-handed the end. If you move the carriage and the crosslide simultaneously, you can cut concave or convex shapes if you're careful. Or you can trash the part in fractions of a second--it's all part of the learning curve. Things worked out fine this time around.

Just needs the clearance hole for the rear breech bolt.

Used the breech itself as the jig. Clamped the breech in a small machinist's vise and bolted it to the drill press table. Aligned through the hole without the plug in place, then installed and through drilled.

Another view.

Blued with Birchwood Casey Perma Blue paste. It's almost a dead-ringer for the Crosman part.

The hammer (striker!) needs a cocking pin. Again, a Crosman part is shown as a reference. A piece of 0.250" O-1 tool steel should do nicely.

Faced off each end and duplicated the part.

Halfway home. Matched the lengths of the ends to the stock component.

The new hammer, breech cap and cocking pin.

Still need a bolt, bolt handle and an end cap for the gas tube, then I think I can slap this thing together. Finally settled on .22 cal. Had to make a caliber decision before turning the bolt. Finding a spare .22 cal barrel from a previous project gun in the parts box sealed the deal.

More to come.

Monday, March 22, 2010

Getting that Beater Crosman 600 Working, Part 2

Well the feed problem needed sorting.

I pulled the cam rod out of the other 600, the new ring wouldn't slide all the way. Again a corner clearance issue. Just wanted to check. Obviously all it needs is the corners relieved in the helix. Better too tight than too loose in my book. But I'm not using this rod in this 600, because it's in the other one...

So I found some 3/16" square and radiused the edges to fit the new ring.

Cut to length and the corners radiused to fit the new ring along the length of it.

I chucked up a 3/16" dowel pin in the 4 jaw and got it true. This saves time when chucking square stock.

Truing up square stock in a 4 jaw is difficult. You have to wiggle the chuck to find the minimum reading at each jaw before adjusting. A little time consuming.

The round section turned on the rod.

I put the good cam rod in the mill vise and set the stop. I lined up a ball endmill with the divot.

Milling a round pocket for the feed arm set screw.

I put the rod in a vise and twisted it with the adjustable wrench held right where the helix ends. Very easy. I was a bit nervous doing this by eye rather than taking 100 measurements, etc. But I doubt the tolerances are that extreme. It has a little bit of play. If I were to do it again I'd make the rod out of stock slightly larger than 3/16" maybe .190" I'd probably also spot for the setscrew divot by holding the feed arm in alignment with the magazine.

The gas leak was no doubt due to the extremely wide valve seat.

I ground up a skinny little toolbit and fed it in carefully to trim the outside diameter of the seat.

The ring is thinner so more force holding it shut.

The last thing I did was polish the lead of the feed arm. I used a cratex bullet and got it smooth. works! I doesn't go full auto and doesn't leak. It feeds fine with 8 pellets in the mag but with 10 sometimes it jams and sometimes it doesn't. I think that it's due to the overall slop (the feed arm was really scarred up) where the pellets go into the feed arm, leading them to cock. If the magazine spring had slightly less force it would probably be more reliable. I'll see how it performs over time.
Now this is not a pistol I have a lot of confidence in. The wear on the sear parts means I'll always have to keep an eye on it. It also makes me less likely to buy a 600 without being able to check those parts before purchase as both of the 600's had issues with those parts (broken link on the other one).

Sunday, March 21, 2010

Getting that Beater Crosman 600 Working, Part 1

I started in on the 600 Derrick sent me.

I bead blasted the frame and gave it some flat black paint.

Next time I will also plug the tube opening...getting paint out of the inside of the tube was a pain.

The feed arm was scarred up.

Rather than make a new ring I asked around and found out that Rick Willnecker at Precision Pellet has them made. The cost is an extremely reasonable $18.00 for a part that would have taken me many hours to make. He also had a bunch of other parts including a link to replace the broken one and a new piercing cap. The details aren't up on his website but he was prompt at getting back to me via email. You can also call him at 717-382-1481
Tell him I sent you! The list of parts he has manufactured includes those used in the 101, 108, 140, 45, 760, 600, 150, 180 as well as many Benjamin/Sheridan parts.

The new ring does have a radius on the corners.

The old cam rod was scarred up on the end.

The ring wouldn't slide freely due to the corners.

So I relieved them.
I put the pistol back together and I had a perfect storm of went full auto, had a gas leak and wouldn't feed reliably.

I looked at the sear elements close up. The sear was worn.

As was the hammer sear. This was preventing them from catching.

I stoned the sears down. While I cleaned up all the surfaces I tried to remove the bulk of the material from the faces denoted by the arrows. I wasn't able to clean them up completely but did get them into better shape.
At this point while the pistol still had a gas leak and wouldn't feed reliably it stopped going full auto. So one problem solved!