Odd BBLs From Numrich

[Olle]

Originally Posted by sheepherder

Brownell's sells a curved lathe tool bit that isn't too bad for a curved tube end. I have 30º/45º/60º 'chamfering cutters' [countersinks] that I use to break the sharp bore edge and blend in the lands & grooves. (I also have tried them for cutting feed ramps; they work pretty well for that too). I'm pretty slack on 'rounding off' the end of thin barrels. The flat squared-off end looks pretty nice to me.

Edit: I just realized which barrel this is. Since it has a threaded-on front sight base, it's not rounded at all. I left it 'squared' and just broke the sharp bore edges with a 45º chamfering tool.

I looked at Brownell's cutter, and the complex grinding explains why I haven't been able to make one... I haven't had much luck with countersinks of any kind, they just shatter at any RPM. My only salvation is a crowning tool set (also from Brownells), but I would like to come up with something that works in the lathe... I hate to buy tools I can make, so I might try and grind a short miniature boring bar before I cave in and order the cutter.