The groove that the barrel drops down into to go out of battery and allow it to chamber a round... Is it possible to cut this with a .750 endmill (plunge cut)?
The plans I have say .40 rad or .80 Dia. I don't have an endmill big enough and I could've sworn I saw somwhere that said a 3/4" was ok.
So if I can use my .750 endmill, how deep should my cut be? I did it to .060 (per the plans), but with the smaller rad, that isn't deep enough to allow the barrel to come out of battery.
I saw a reference to that in one of the build threads, and a 3/4" end mill was recommended.
My drawing shows a 0.348" radius and the barrel is ~0.685" diameter in that area so 3/4" should be more than ample. Make sure the hang up is not in another area.
JCH, do you have the depth of the cut on those plans?
Anyways, I did the math and go about Sin X= 0.9375 or 69.6 degrees. However, I don't understand why this method wouldn't just leave you with a truncated cone looking cut. I know it must work, seeing as how Steven Horace wrote an entire program for it. Oh, speaking of which, the program cuts out when I enter cutter diameter to be used.
Could you explain to my inexperienced mind, how cutting like this works? Clever Idea.
You tilt the head and cut with the edge of the end mill. You are effectively cutting with the side of an ellipse. This is only good for narrow portions of a larger radius.
The simple formula is: cutter radius/generated radius=the tangent of the angle
The DOS program just makes it easier to figure out the best cutter size.
A 5/8 cutter @ 60.02 degrees will yield your .348 radius with a .0007" error.
The print I have does not show a depth. 0.060" sounds like a starting place as that is about the depth of the groove between the lugs on the barrel. I would increase the depth by about 0.005" at a time until I got it to function.
I am kind of feeling my way with my build, but I have a Colt 1911 & a Rock Island Armory for comparison. The depth of the cut on the Colt is 0.074", the RIA is 0.078".
I never really thought about where that measurement came from...Huh. Now I know. I believe I have it cut to a decent depth. I went to about .068" ish, and it seems to crisply unlock from the slide.
My other question: Will a 1911 cycle (under fire) upside down? I can't rack my slide unless it's close to perpendicular to the ground, which isn't a problem... I just wonder about when I'm in the middle of a shootout when the zombie apocalypse comes.
The racking of the slide should be purely mechanical, the link pulling the barrel in and out of battery.