Drill Doctor or cobalt bits

[380mxc]

Originally Posted by DanH

Hey, is there a good sharpening machine out there, one which won't break the bank?

Optima! Does not meet the criteria for the bank part though.

[Don]

I have a Drill Doctor and I've been satisfied with its performance?but not until after I figured it out. There was a learning curve and as simple as it is to operate, I don't know why. There seem to be two "tricks" if you will. The first is simply following the directions to line the bit up in the holder so you sharpen the correct angles on the bit. If you don't get this step right, your bit won't come out sharp. The next "trick" is to take an even number of light passes. It doesn't take much unless you've abused the bit, in which case, Sam B's sharpening method is what I'd use.

I wasn't happy with my initial results and after some frustrating results I took an hour or so and carefully read and followed the directions and practiced until I got decent results on 1/4" bits and larger, then proceeded to apply what I'd learned to the #30 and #40 bits. They're harder to 'feel' when they're in the bit holder correctly and harder to keep in alignment while you tighten the holder.

And of course the disclaimer - I am not affiliated with Drill Doctor other than owning one.

The other thing I'd recommend is buying at least decent quality bits. Avoid the cheap ones as you'll regret the purchase. I have a full numbered and fractional set from Harbor Freight and they're not decent quality bits (the box and the price are the two best things going for them). I happen to like the bits Bob Avery sells but I'm sure others see bits just as good.

[mike newall]

The big box of drills from Harbor Freight or Northern tools is good. Then go buy 5 each of the cobalt drills in common sizes from Spruce - 40, 30, 19, 10 etc.

You wear those out quickly, the others only get used occasionally.

[Mike S]

Originally Posted by DanH

Hey, is there a good sharpening machine out there, one which won't break the bank?

Yep, a good bench grinder, with a good wheel-------and a bit of operator training, and a lot of practice.

If you know any old time machinists, talk to them. Drill and tool bit sharpening is one of the first things you learn in a machine shop.

This guy has it correct----at least as I learned to sharpen drills way back in high school, and in the machine shop. http://www.youtube.com/watch?v=-wXBbbDVksk

[acroflyrgirl]

Originally Posted by Sam Buchanan

The best way to sharpen #30 and #40 drill bits is to hold them firmly between thumb and forefinger as you make an underhanded swinging motion in the direction of the nearest garbage can. Release the bit at the apex of the swinging motion, with practice you can launch the bit with a graceful trajectory into the can with one attempt.

Originally Posted by ColoRv

Underhanded? Seriously? Like girls softball?

Personally, I throw anything under 3/16 at my hanger mates Piper Cub. Five step drop, Manning goes deep to Thomas.... Broncos beat the SeaTurtles 51-3 in New York!

It's remarkably difficult to penetrate that fabric with a #40 bit!

Who would have thought I could be so entertained while learning about sharpening theory here on VAF.
Too funny y'all. Too bad about the little Denver ponies, going to get sent to the proverbial glue factory in NY by the Seahawks.

[koda2]

I bought a Drill Doctor twice. You know the old saying, "Fool me once, shame on you, etc."

The first one was the old vertical Green model 750. Top of the line. Worked for about 50 to 100 bits before becoming unserviceable. Called the company, and ordered "overhaul" parts. Never could get it to work.

Was told the new gray model was much better. Spent more money. It worked only for bits in the 1/4" to 7/16" range. Others no good. Wasted more Franklins.

If you look at the machine, the working parts are plastic. Once wear starts, the alignment and tolerances go out the window. IMHO, the newer model has even less support in the rotating mechanism. Plus the adjustment range of drill relief angles wasn't even in the ball park.

Darix makes drill sharpening machines that are orders of magnitude more expensive for production work, but I'm not buying any more of their stuff.

If you Google "drill sharpening" and "4-facet bits", etc., you can come up with some interesting stuff. Like making your own sharpener for small bits. Down to #80. But it takes a lathe and a mill to do it. If you have a lot of time and energy on your hands you can probably make it work.

The problem with sharpening small bits for aircraft aluminum use, is, that the bits wear in diameter as well as at the tip, and can affect rivet fit, etc. In machining work, drill bits are like horseshoes, getting it close counts. Then you ream for exact fit. So sharpening bits may be the way to go. For aircraft sheet metal, you can't afford to ream #40 holes.

My 2 cents.
DA
6A build