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Gunsmithing Why not cut chambers with a single point cutter?

persistant7500

Private
Full Member
Minuteman
Oct 27, 2009
44
1
55
Buckeye AZ
I am sitting here looking at reamer options for a rifle I am planning when the though hit me "why not single point cut chambers on the CNC lathe instead of buying different reamers for everything I want to do". I know most smiths do not have cnc lathes but is there a reason that this wont work or might not be recommended? I program for internally bored parts all day for work but I'm still doing my chambers old school, but maybe there is something that I am not thinking about. Thank you for any thoughts Jeff...........
 
If you have a rigid cnc machine with good ball screws & the right tooling it's doable. Boring bar / tool deflection and getting a good finish would be two advantages of a reamer but not having to buy every reamer give advantage to the high performance tooling.
 
I am sitting here looking at reamer options for a rifle I am planning when the though hit me "why not single point cut chambers on the CNC lathe instead of buying different reamers for everything I want to do". I know most smiths do not have cnc lathes but is there a reason that this wont work or might not be recommended? I program for internally bored parts all day for work but I'm still doing my chambers old school, but maybe there is something that I am not thinking about. Thank you for any thoughts Jeff...........

Tool deflection: very small diameter, very deep. Also the interrupted cut in the lead may result in some surface finish issues.
 
The tool deflection issue is a consideration but if you pre-drill like most do anyway I can fit a much stouter bar into the bore. We grind our own solid carbide boring bars at work, I think I will have to draw one up and trade a couple cases of beer for one and see how it works out.
 
It's been done in both long and short range benchrest. A 1K competitor who I believe no longer shoots did a lot of things outside the norm including CNC single point chambering. He won a lot so I think it can be done quite successfully.