1903 Springfield barrel threading

[RRHK]

Hello everyone,
I am looking for info on dimensions for grinding a square threading tool for cutting threads on 1903 Springfield barrel on the lathe. From what I have been able to determine width is about 0.053 but what I can't find are the clearance angles for the front and sides. I was considering a 10 to 12 degree angle. Anyone have better info or experience. Thanks! Richard

 

[mbogo3]

Maybe call Nick at Vulcan Gun Restorations ,he re-barrelled a 1903 for me last month. He would know.

 

[guntech]

Hello everyone,
I am looking for info on dimensions for grinding a square threading tool for cutting threads on 1903 Springfield barrel on the lathe. From what I have been able to determine width is about 0.053 but what I can't find are the clearance angles for the front and sides. I was considering a 10 to 12 degree angle. Anyone have better info or experience. Thanks! Richard

If I understand the question correctly, the actual clearance angle should be enough so the tool does not 'drag' when engaged but not so much as to weaken it. I hollow ground the side and front edges as little as possible on square thread bits. 10 degrees should be fine.

 

[9.3mauser]

Is this any help?

 

[RRHK]

View attachment 638891

Is this any help?

Thanks for the drawing, it does confirm the width of the tool and I think with the info others have provided I will try a 10 degree rake on the tool and cut a dummy shaft before I tackle the barrel

 

[guntech]

I usually cut a dummy thread just to confirm the tool grind.

 

[tiriaq]

Yes. Confirm the setup before starting on the good piece.

 

[Blastattack]

That’s really simple trigonometry. That thread has a lead angle at the root of ~1.8 degrees, slightly less at the OD. I personally won’t waste my effort with tool grinding. This is the perfect application for a grooving insert.

 

[RRHK]

That’s really simple trigonometry. That thread has a lead angle at the root of ~1.8 degrees, slightly less at the OD. I personally won’t waste my effort with tool grinding. This is the perfect application for a grooving insert.

I sure would be if I had one and the time to order one. I've been working on this this week and have ground a tool that is pretty good and have cut a dummy thread that works, thread groove seems a little wide with a .053 cutter, so I'm going to try a .051 width to see if I get a better result.

 

[Leeper]

Set on center, the tool clears the work fairly quickly. A 2 degree angle is fine. grind the cutter on the leading edge. The cutter doesn't need to be any more than .150 long. I grind the tool to .050 and offset it for the final cut, to provide clearance.