rich-at-home
Plastic
- Joined
- Mar 7, 2015
I'm machining up an air rifle barrel blank and this particular barrel needs a taper cut at the breech end.
The taper is just a tad under 5 degrees and goes from 6mm dia down to the bore size, 4.5mm.
I'm using a tiny solid carbide boring bar.
The taper is fine but when I get to the rifling, I am getting a burr where the steel is peeling over into the rifling grooves.
At higher speeds (1200 rpm) this is worse. At low speeds (180rpm) it's better but still visible. I'm using cutting oil as a lube as the low speed.
Not sure if I should try and clean up the finish by using abrasives or keep machining at the low speed and see if it eventually clears off the burrs.
They don't occur on all the lands and they are only at the base of the land where it rises from the bore.
Any advice?
Cheers!
The taper is just a tad under 5 degrees and goes from 6mm dia down to the bore size, 4.5mm.
I'm using a tiny solid carbide boring bar.
The taper is fine but when I get to the rifling, I am getting a burr where the steel is peeling over into the rifling grooves.
At higher speeds (1200 rpm) this is worse. At low speeds (180rpm) it's better but still visible. I'm using cutting oil as a lube as the low speed.
Not sure if I should try and clean up the finish by using abrasives or keep machining at the low speed and see if it eventually clears off the burrs.
They don't occur on all the lands and they are only at the base of the land where it rises from the bore.
Any advice?
Cheers!