Four Facet vs. Split Point

[sfriedberg]

rimcanyon, how do you set/clock the rotation of the drill flutes when tightening up the collet block? Do you have a setting fixture?

 

[Clive603]

rimcanyon

Nice design. I shall steal some of your ideas when I finally get round to doing a four facet grinder to handle my bigger drills. Mr Clarksons excellent attachment only goes to 5/8".

Presumably you use a set-square style device to set the cutting edge vertical.

One change I will make is to spring load the feed to reduce risk of overfeeding damaging the wheel. My Clarkson attachment has a sprung plunger allowing about 1/8" backwards shift to help tame overfeed. Ashamed to say that I've needed it on a couple or three brain fart moments!

Getting back to the original question.

In my view floor to floor time needs to be minute or two if sharpening is going to make sense. So the extra time needed to do a split point or the extra cost of a sophisticated sharpener able to do splits may not be justifiable.

That said how expensive would it be to set up a fast point splitting jig with its own wheel rather than use the pukka sharpener. Surely a cheap import grinder will be up to the job. Need to make a special rest of course. That way you can probably do just fine with one of the less expensive and less sophisticated sharpeners that just do a good job on an ordinary point. If I were buying a basic sharpener to team with a stand alone splitter the Kaindl BSG 20/2 https://www.kaindl.de/en/bohrerschleifgerat-bsg-20-2.html looks attractive, about as quick to use as my Clarkson and potentially inexpensive.

If you wanted to bugger around with DIY I guess a Kaindl style wouldn't be hard to make especially if you use a collet block for holding as per rimcanyons system.

Never seen the point of vast inherent adjustability in sharpening devices on the shop floor. Fast turn round and exactly repeatable results are what's needed there. Even if quick'n easy sacrifices a bit of life and cutting speed over best.

Clive

 

[rke[pler]

I'd love to have an Optima, but can't really justify the cost. I missed one at auction a few weeks ago, last bid would have been $823 w/fees & taxes. Kicking myself now, as it was well tooled, although I would have been bidding blind - it was 110 miles away, which made inspection difficult. Of course, you don't know how high the other bidders were willing to go.

Both of my Optimas are from auction. First one was in an instrument auction - basically lab gear. I paid $100 for it set up with a diamond wheel but no chucks. Second one was also auction (maybe $400) and was completely tooled and has the point splitter. When I want to split carbide I just put a diamond wheel on.

I'm pretty sure the Optima makes the modified split points.

Of my drill grinders I like the Optima the best - you can walk right up and grind a drill in less than a minute with the optical setup. But I will use the Christen 05-10 (also an auction purchase) for bits smaller than 1/8 or so. It's more finicky than the Optima and takes a bit to be comfortable with it. It might be that I have to use a microscope with the point splitter.

 

[rimcanyon]

rimcanyon, how do you set/clock the rotation of the drill flutes when tightening up the collet block? Do you have a setting fixture?

A small square to set the cutting edge vertical. Actually I set it slightly advanced from vertical so that when the 10 deg. facet is ground the result is vertical.