drill doctor

[BGHansen]

I have a DD 400 (older model) and have had very good success. Like others do larger bit by hand using a General gauge for angles/depth.

Bruce

 

[jim18655]

I have one and it's OK after the learning curve. I found out the relief isn't correct and you need to set it a little more otherwise it makes a sharp bit that won't cut. Also, you need to reset the bit in the holder if you need to remove a lot of material or else the center setting changes too much.

 

[maker of things]

I have the 500 and like it so much I bought one at work too. Many of the guys could never get a good bit out of it. Turns out it's a machine, like many others, that there is a technique required in order for it to work correctly. I think the idea of it being a "drill bit sharpener" throws some people off. A "pencil sharpener" more or less sharpens the pencil when you just stick it in there, while the DD is really a bench grinder with alignment fixture. If you don't set it up per the instructions, the bit will not get sharp in any way that is useful to you. I had to reread the instructions several times I sharpened bits before the order of operations and proper alignment stuck in my brain.

It probably doesn't help that most of the time we are trying to sharpen bits we are just trying to real quick get something done.

 

[Bob Korves]

I have one and it's OK after the learning curve. I found out the relief isn't correct and you need to set it a little more otherwise it makes a sharp bit that won't cut. Also, you need to reset the bit in the holder if you need to remove a lot of material or else the center setting changes too much.

Yes, the "tooth rest" contact point makes a difference in all these jigs. Drill extension beyond the tooth rest changes the geometry of the grind. Different helix angle drills also require different amounts of stickout beyond the tooth rest. It also matters how aggressive of a grind you are trying to achieve.

 

[Groundhog]

I have a DD 750 but also sharpen by hand. I think the success with drill sharpening comes more with knowledge than the apparatus. I've seen people who can't sharpen a simple drill with the DD because the do not use it properly (like not getting both flutes even), just as I've seen people who can't sharpen a drill by hand because they haven't learned how - free hand or with a jig.
Either one works for me and is easy once I learned how, but before I learned the finer details of either method did not produce very satisfactory drill bits.

 

[4GSR]

I had a DD 400 or 450, I don't remember now. It did okay on sharpening bits. Upgraded to a 750. What a POS! Could not get one single bit sharpen where it would cut! My hand ground sharpen one cut much better! I also have a older Dartex M-2 I use now. So much easier to sharpen using it over the 750 in my opinion.

 

[Wreck™Wreck]

I could be wrong, but when I was in school we were taught drill, bore, ream if you want accurate hole. If your drill takes a turn east or west while drilling, the reamer will follow it. A sharp boring tool will more likely straighten the hole out, then ream to final size.

Boring is a precision method of making holes itself, if you set up for boring why not just bore to size and skip the ream?

 

[Doubleeboy]

Boring is a precision method of making holes itself, if you set up for boring why not just bore to size and skip the ream?

Beats the tinkle out of me, maybe because a fresh reamer gives a better surface finish.

 

[Artie]

I have two of the original 750's that I purchased cheap (nos). Supposedly the motor on the originals were more robust. It was frustrating establishing a repeatable technique with satisfying results.
The DD is great for touchup sharpening once the learning curve is achieved. For really dull or damaged bits I first rough with the bench grinder and finish up with the DD.
I have an inexpensive Northern Tool Klutch stand/mount that converts a 4 1/2" angle grinder into a mini chop saw. It's perfect for sizing old jobber drills into stub/screw machine bits. After hand grinding/roughing with the grinder I finish up those too with the DD.

 

[Wreck™Wreck]

Beats the tinkle out of me, maybe because a fresh reamer gives a better surface finish.

Have never seen this in practice though in some instances it may be. Having to reverse the tool out of the hole often leaves visible artifacts on the surface.