Originally Posted by LRF
Originally Posted by Cold1
I am not a machinist, so how do you get the 90 degree inside corners in the receiver for the breach block? Broach?
There are many ways to do that, broaching, filing in using "file fixtures" similar to methods used in the 1800's by gun makers*, casting and wire cutting/EDM.
This projects receiver started life as a Rodney casting then I have modified it. Also to insure the mortise was true I did take a skim cut using a Wire EDM. So you can see many ways to skin the kitty. On the floor plate which has a much more complicated mortised thru slot I have milled and filed it to shape and will also use broaching to complete the final work required on it.

* a task generally reserved for the apprentices as it was hard physical work.


Thats what I was afraid you would say. I attempted several different ways, Filling, using a corner broach in the mill, yelling at it, cussing at it, etc... I eventually got smart and figured out CAD enough no make a print and sent it out to one of the online machining companies. I was able to get 4 made at a very reasonable price. Mind you these where just the mortise cut into a block of 4140 and not other work done to the block.

That project was coming along nicely until i got side tracked on new projects.