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Drill bit sharpener

dareha

Member
A sharp drill bit makes it so much nicer and let's face it we use a lot of drill bits. Is there a good drill bit sharpener that sharpens at the correct angle for what we do? Or is it cheaper to just buy new drill bits.
Thank you.
Darrell
RV 9A
 
A lot of people have used the Drill Doctor and have raved about it. I bought one based on the reviews and truthfully I haven't had the best of luck with it. I've only tried it on the smaller bits so perhaps results are better with the larger ones. The most common angle I believe is the 135 degree split point. For #30 and #40 bits I would by a bunch and discard them when they stop performing. YMMV
 
Drill Doctors will make your drill sharp but the web will be off center and the drill bit will drill over size. Buy small drills in packages of twelve. McMaster or MSCdirect.
 
For me it's hit and miss with the Drill Doctor for the small #40 bits. I always test drill and re-sharpen if it's oversize.

It does seem chintzy but it works OK. Worth the money IMO.
 
Drill Doctor

I had a Drill Doctor thrown in "free" with a new wire welder deal. After a couple of years I threw it in "free" on a plasma cutter trade in. My shop is a better place now.
 
I do a bit of hobby machining and watch my share of machinist type videos on youtube. The collective wisdom seems to suggest that no matter how you sharpen your bits, IF you are good at it and they seem better when you finish, you are always better off buying new if the size is less than 1/4" and some use a larger size minimum than that because the price point for small bits doesn't justify the time and likely imperfect bit.

Most of the experienced guys sharpen them by hand on a grinder.
 
I built a slow build RV-7 and guess I've gone through about half a dozen cobalt #40 drills and about 4 #30 drills. If you get cobalt aircraft drills you'll never be able to justify needing a drill sharpener, let alone the frustration of not having a perfectly ground and easy to control bit. A roofer here told me that drilling steel roofing sheeting they would go through half a dozen drill bits a day, at $6 each. I told him I could get some cobalt aircraft drills for him, and because they were so cheap, he ordered 50. I saw him a few months later and asked how they were working. He was still on his first cobalt drill. I guess he's got himself a couple of lifetimes worth.
I have developed a policy of only buying cobalt bits, and when I'm no longer happy with they performance, I retire them to the tractor workshop on the farm where the mechanic can sharpen them on a grinding wheel and continue to use them on farm machinery. Knowing I can keep a bit centered and not botch a part is far more important than saving a couple of dollars on bits.
Tom.
 
I have one of the more pricey models of The Drill Doctor and have never been able to get a good sharpening with it, even on larger drill bits. I find that the goofy clamping fingers that hold the bit after you get it set up and positioned, tend to twist the bit out of place when you tighten it up and I ended up giving the bit a sharpened tip that was not usable. I used to be able to get good bit sharpening's by hand on a consistent basic back in the 70's when I did it daily working in a prototype job shop as a checking fixture builder, but its rare I hit it now. Buy good quality drill bits and throw the #30 and #40 bits out when they get dull. Even good quality bits are pretty cheap IMHO. I prefer to ream for final size though and seldom drill.
 
I had the top of the line drill doctor even took it to the factory for adjustments. Then threw it away. I felt much better after hearing it hit the bottom of the dumpster! Life is better now. :))
 
I've had a DD for years, and yeah its worthless on the smaller sizes we use. 3/16" and up, it does a good enough job. A better chuck design would make the smaller sizes work, but clearly its not in the cards at this price point.
 
If you can find a used Black Diamond industrial sharpener try to snag it. I found one on CL for $250 with all of the collets, number and fractional, up to 1/2", on a factory stand.
They still sell these new for about $5k ! They are amazing.

Even at that, you can buy a lot of RV sized drill bits for $250. I use mine typically for larger, more expensive, bits where it is worth my time.
 
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