06-04-2013, 06:34 PM
(06-04-2013, 06:17 PM)EdK Wrote: After contemplating a lot of grinding on an old end mill, I vaguely remembered that I had bought a couple of small solid carbide boring bars off of ebay some time ago. Surprisingly I was able to find them in quick order.
Anyway, it looks like the smallest of the two might do the job. My question is whether a boring bar this small is up to the task without risk of snapping in two? The material is 1018 CRS direct from our friend Russ. Any thoughts?
Thanks,
Ed
Ed, do you have "any" flat bottom drills under 1" dia.? Tom brought up a good point (but it may be cost prohibitive to grind a 1" drill....they're not cheap) and could get you done pretty quick.
I'm sure you thought of it already, but never know.....sometimes it is the simple things that get overlooked. Rough with the drill to remove as much as possible then finishing up with a larger boring bar would be much easier.
You certainly can use the tool pictured, but keep your DOC low and your speed high, especially in the center or you risk snapping that bad boy in half. I would not go much more than .010" deep but keep your RPM maxed (how much do you have?) and your feed around .002"/rev.
The high speed steel will be much more forgiving at that size.....slower to machine.....but will allow you small errors in your approach. The carbide will go bye-bye in a blink if not optimized, and you may just end up dulling it up feeding by hand whereas the HSS can be run slower and feed by hand.
If it were me.....I'd opt for making a HSS tool.....a dull EM can be made into a boring bar in few minutes and even if it's dull as a fart, once you have one flute left touch it up a bit to sharpen by hand....no need to worry about anything as long as it's the highest point on the bar and pointed in the right direction!
Later,
Russ
BTW.....we'll be expecting pictures, and video.......at least I'll understand what the hell you'll be saying.....unlike that other film making foreign guy from across the pond!
Later,
Russ