New to me Sterling drill grinder

Aukai

H-M Supporter - Diamond Member
H-M Lifetime Diamond Member
Joined
Oct 4, 2016
Messages
7,164
My wheeled chair, and my orthopedic walking boot got a work out today pushing the chair around. I have been out of the garage for too long! So I was able to clean, and operate the drill grinder today, I replaced the wheel that it came with just out of precaution. The diamond dresser needs a Time-Sert as the threads are stripped, the motor is 240v 3 phase, and runs like a champ on the RPC. I dressed an 11/16 drill bit, but the chisel point looks a little wide to me, but with a pilot hole it should do all right I think. I do not have the 67 1/2 guide plate for the 135* point, so this is cut at 140* with a 70* guide plate.

 
Sterling does not make a 67 1/2* guide for 135* points, so my 135s will get 140* points as needed. I also did my first "large" bit yesterday with a 118* point, it takes quite a few passes, but it came out well.
 
I'd need to see the side 3/4 profile as well, but that example above looks like you've got your setup correct. The chisel is at a perfect 135/45 angle, and appears straight. That means you have your clocking correct. Your cutting edges are straight for clocking and point angle. From only the one picture, it looks like your swing extension and clearance are right, but I need to see the side of the bit. I'm betting it's good, though!

The only thing left to do is thin the web. Be careful when converting 135 drills to 118s and vice versa because at some point the helix angle will leave you with a curved cutting edge.
 
I did try my hand at thinning, when I get out there I'll take a picture. It looks easy but it actually takes some fiddling around to start getting a good grind. That's why the web got fat
 
More pictures, one flute is straight(er), and this one is curved

 
Back
Top