Threading a barrel question.

[jscandale]

With carbide inserts like the one in the pic above, I cut at about 350 rpm. I have cut at faster speeds but the you just have keep a careful watch on the thread dial and catch it just right. I have cut at 600 rpm, but the thread dial starts to look like a circular saw blade. At 350, it's still easy to catch and produces a smooth chatter free or tear out free finish. Keep in mind that carbide likes pressure and speed. High speed threading inherently produces the additional pressure that carbide like and produces a cnc quality finish every time.

For a square thread on Grarand and Springfield 03 barrels, I use a similar setup with a carbide grooving insert instead of a V groove threading insert on a "top notch" type bar with the compound set at 90°. Since the thread fitment is especially critical for a square thread, this method produces a very satisfying result.

JS

 

[jscandale]

STS,

Keep in mind that the part in the pic is a sizing die and has a very large relief cut by design. AR15 barrels require a very narrow relief cut at the shoulder because the extension is threaded all the way to the mating surface. On a Rem 700 action the relief cut is only as wide as the V cutter since the is a non threaded section for a recoil lug. Same goes for Savage/barrel nut. Winchester or any other action type with integral lug gets a relief cut as well.

Keep in mind that I didn't invent this method, just adopted it from a man with 25 more years experience than me. I'm 44 and have run all kinds of machines over the years and still learning stuff all the time. I just love it! ;D

I have seen the Warner tool holders and insert and they look like top quality items, but I just prefer to use carbide, high rpm, and lots of coolant whenever I can since I am doing a lot of profiling where heavy cuts are common. HS just wont stand up to the constant abuse. I do use HS to finish all flat tenons like gas block tenons and front sight tenons since HS is inherently sharper and works better with light cutting (.001-.008") where there is much less tool pressure.

JS

 

[STS]

It's all good my friend. That's what interesting about this stuff. There are so many different ways to arrive at the same place. Happy threading.

 

[jscandale]

I just though I would post these. All advancements are on the diameter.

JS

 

[swampers]

Cool pics. Looks like you have done that a few times.