Sunday, May 5, 2019

Installing Crosman's Two-Stage Trigger on a 22XX -- Part 2

Working out the final details of the two-stage trigger installation, I noted at the end of the last blog that that, "A stock 22XX hammer will ONLY work if you pull and hold the trigger to the rear while cocking the gun.  With the bolt pulled completely to the rear, let go of the trigger and the sear will catch.  Yeah.  Great.  I've read that the hammer from a Crosman 1701P will solve this problem.    I've also read that a 1701P hammer will ONLY work in the 22XX gas tubes.  It's too large in diameter for the smaller 13XX compression tube...Of course, I found out about the hammer after I'd ordered all the other pieces parts from Crosman.  Rather than another order and another week for delivery, I made a couple new hammers."

Here's the hammer from my 7 or 8 year-old Crosman 22XX.

The new two-stage trigger sear hangs up on that big groove in the middle.   One easy "no machining solution" is to simply fill the groove with something like JB Weld epoxy.  Probably not even necessary to fill the entire circumference.  Just the bottom area where it rides over the sear should be sufficient.

Also note that this is an earlier model hammer for the forward breech mounting screw.  It does not have the clearance cut at the front to work with the newer breech screws that are accessible only after removing the loading bolt.  So, there's one less machining step for me.

To make a new hammer, I used a piece of 0.750" diameter W-1 (the W denotes "water hardening") tool steel.  

All dimensions came from the removed Crosman hammer.  Turned the OD down to 0.739"

Chamfered the end.

Spotted for the hammer spring hole.

And drilled 5/16"

Cut to length and turned the angle on the front for the sear.

Went to the mill, did some quick edge finding and spotted for the hammer pin.

0.125" drill.

A 3/16"  (0.1875") end mill was used to cut a short counterbore.

Pretty much done.  Not gonna worry about matching the exact weight to the original. 

I'm sure it was usable as it was, but I did a quick and dirty heat treat to the face of the hammer to keep it from wearing.  Heated it to critical temperature and quenched.  A bit of tempering brought down the hardness slightly.  Polished it up and installed. 

Really like the adjustment range of the two-stage trigger.  With that window cut in the side plate it was very easy to see exactly what was happening as the first and second stage were dialed in.

Thanks for checking in.  More soon.