Another Breech for a Crosman. Part 4

Working on all the small breech items to get it up and running.  I'll gloss over most of this since we've covered it on past 22XX builds.














Spun the bolt on the Taig lathe from a piece of 0.250" diam stainless steel.

Flipped it around and trimmed it to length.

Moved it over to the milling machine and found the edge.

It's supported on a single parallel.

Spotted and through drilled with a #29 bit.

Tapped #8-32.

Used another piece of stainless for the bolt handle. 

Threaded #8-32.




















Stepped down to fit in the breech slot.

Rounded over the end of the handle. 

Simple and clean.

Cut an extended cocking pin from O-1 tool steel.

The factory part is on top.  There's a bit of a length difference.

Cut down a 24" Crosamn .22 caliber barrel to about 12" and cut a new crown.

Found a piece of 0.750" aluminum tube in the metal stock box.  It's got a 0.500" hole in the center.  Used the larger lathe and a cut-off tool to cut a piece to size for a barrel sleeve.

Cut a 0.625" step on one end of the tube.

This will recess into the front of the breech.  Not shown:  Cut the tube to correct length to fit over the barrel and finished the tube with an oiled scotchbrite pad.

Figuring out how to secure the muzzle end of the barrel in the sleeve.  Thought I'd try a simple o-ring.  Cut a groove.

 Found a suitable o-ring.

 It press fits into place.

Aside from a transfer port, it's functionally done.  Aesthetically, I think it still needs help.


More soon.

Another Breech for a Crosman. Part 3

Finishing the breech today. 















With the bolt handle slot cut, there were just a couple more procedures to attend.

Centered on the rear breech screw hole and counterbored for the head of a #8-32 socket head cap screw.  The counterbore was done when I could drop in the #8-32 fastener and the head was just below flush.

Dovetails!  Before cutting dovetails, I took a couple passes on each side to leave a center rib just shy of 12mm wide.

Followed by a small 60 degree cutter.  The work was only cut from one side, then turned around in the vise with the Y-axis locked.  This puts the dovetails in the center of the workpiece.  There's quite a bit of variance on what is known as a 3/8"--or 11mm--or .22 dovetail.  I cut until a Leapers medium scope ring would tighten with minimal gap on the clamping plate. 

At this point, the breech is done.  Boring, but done.  Those plain slab sides needed something to add some visual interest.  Set the milling table stops and used a Woodruff key seat cutter to add horizontal slots along the sides and break up the smooth surfaces.

Before clean up.  Click any pic to make it larger.

Wet sanded (WD40) to 500 grit on a surface plate.  Slots left in the raw.

Wanted a tad more sprucing up.  Used a maroon, then gray Scotchbrite pad to polish the breech.  Various riffler files were used in the slots to remove the cutter marks.  Did minimal clean up of the dovetails as I was concerned about the accuracy of the angles.

Breech is done and I'm satisfied with how it looks.  Still need to make all the incidentals--the loading bolt, bolt handle, cocking pin, transfer port, barrel sleeve...

Thanks for reading.  We'll have more in a few days.

Another Breech for a Crosman. Part 2

Right where I left off...

























Picked up the edge of the breech then cranked the table to center.

With a 7/8" ball mill, I cut the radius to fit against the gas tube.

It was a pretty slow cut and produced a lot of chips.

The last pass was done at high speed taking off about a thousandth.  Gave an acceptable finish.

Back to the mill (after some chip clean up) and spotted the hole for the rear breech screw.

Through drilled.

Drilled for the forward breech screw.

0.250" hole for the transfer port.

Set the X-stops.





 













Milled the slot for the hammer cocking pin.

Not shown:  Drilled three #29 holes for barrel set screws.  Went through the small taps and found a #8-32 plug tap.

Tapped.

Flipped the breech--this is the top--and countersunk the rear breech screw hole.

Left turn(side), Clyde.  Set the table stops for the bolt handle slot.  That's a 3/16" end mill.

A few passes later.  Yep, cleaned up the chips before taking the picture.

This contraption is a tilting table.  Allows the work to be angled relative to the spindle.  I set it at about 12 degrees fahrenheit.




 













This is a train wreck.  The breech is in an insert vise that's been bolted and step-clamped to the top of the table.

All for this little cut.

Should let the bolt handle angle downward when locked in the forward position.

Marked out the location for the loading slot.

0.750" end mill looked about right.

Just breaking through the 0.250" through hole for the loading bolt.




 













Luckily (OK, I did actually measure first) I didn't break through at the front into the 0.4375" hole for the barrel.   Would've still worked though.

Lined up on the front breech bolt through hole...

and counterbored for the head of the fastener.



More in a couple days.