Friday, June 28, 2013

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.