How do you sharpen you drill bits?

BGHansen said:
I use a Drill Doctor 750 for most stuff. Bits over 5/8" are hand-ground, use one of those cheap General protractor/drill guide to check the angle and depth relative the center.
Bruce
Click to expand...

I place drills into basically four classes. There are the ones that are too big for a Drill Doctor. The "small" chuck version. I have a Darex "commercial" grinder that handles 1 inch, but it is a pain in the wazoo to use. They get done by hand on a low speed "water" grinder. The Darex grinder has many adjustments, but many of the really large drills are carbide tipped masonry drills and don't work on the wheels anyway. They must be done on a "green" wheel.

Then there are the ones that can be done on the Drill Doctor. Essentially, 1/2 down to 3/32 inch. That varies some, depending on how much I shake at the time. And how my eye feels. Losing vision in one eye cut into close work quite a bit. But they cover a majority of the drills. Metric (1-13mm), fractional(1/16-1/2"), number(1-60), and letter(A-Z) sets.

Below that, roughly Nr 55 down to about Nr 70 are also done by hand. Including a few of the fractional sizes. But on a Dremel with a "cut off" wheel. And under a bench glass so I can see what I'm doing. It is questionable how accurate the work is, but they cut well enough. For tap sizes, I don't depend on the full strength of the threads, so can use a slightly oversize hole if it comes about. Just how strong is a Nr 3/0-120 machine screw, anyway?

And lastly, from about Nr 70 down, the drills just get replaced with spares. I have tried to sharpen them, but it was debatable even when I was young and had good eyes.

A Nr 60 is the imperial equivilant to 1.0mm at 0.040". A Nr 80 is 1/3 that at 0.0135. The really small sizes are usually so a wire can be inserted. So final size is not that critical. I keep several sets of cheap drills for that specific purpose.

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After sharpening a drill, one can drill a test hole and see what kind of a job you did. I aim for a nice pair
of spirals but don't always get it on the first try.
 
I hear people say it’s not worth it to sharpen drills. When I had a production shop I would put all my dull drills in a bin. Then when I had a job with a slow operation like a 10 minute drill or boring time I would be at the machine and sharpen the drills in this dead time As I was watching the machine. So in my mind I was not wasting time sharpening drills. I was saving money.

Jim Sehr
 
Mine are very frequently one sided :(
 
I most definitely think sharpening your cutting tools is a waste of time. I have some that I use and they are such a pleasure. Sadly when I'm enjoying those moment, I think about when they no longer bring me happiness. I really would like to be able to sharpen....WELL. I looked over the PDF download here, I just can't focus on that. It like reading a book about quilting Ugh. I tried today with a VERY worn out drill bit. I did it free hand, just to kind of understand the angles (and who doesn't fantasize they are some sort of savant??) Anyway...I don't have any amazing, undiscovered skill.
Back to my point, I wish that was a skill I had, I'm willing to learn, but I'm not a boring/dry book reader....at least not if I'm hoping to retain info
 
I think this happens to a lot of us, but working on my tools has superseded actually using my tools. Taking time to learn to fix up and restore my tools instead of throwing them away has become a hobby in itself, so I have no problem spending a lot of time working out the best way to sharpen drill bits.

Also on the topic of reading boring things..... well, yeah. I've got a pdf of Connelly's machine tool reconditioning book, and have been using it as a bedside reader. It puts me to sleep, but at the same time it really makes me want to do the things the book is talking about, like watching youtube videos of people making stuff excites me to start new projects.
 
pontiac428 said:
This is a book in our (HM's) download library that I find excellent as a reference and keep near my sharpening station.
www.hobby-machinist.com

38 - Tool and Cutter Sharpening.pdf

Imported files from vBulletin files system.
www.hobby-machinist.com www.hobby-machinist.com
Click to expand...
I have a copy of the actual book. But I was very concerned that, almost right off, he says to use the side of the wheel. Can't even remember how many times I've been told NOT to use the side of a grinding wheel! So, am I being paranoid ... or is his technique a bit iffy????
 
Using the side of the wheel is the cheap alternative to buying a cup wheel for a bench grinder, which is in turn a less expensive alternative to buying a tool grinder. I am sure that is all it boils down to.

A few bits shouldn't hurt, but if every kid in metal shop started hogging the side of the grinder wheel, I'm sure the shop teacher would be teaching them to not do it as gospel. Use your good judgement.
 
There's a "knack" to it sharpening a drill. Would a video on hand grinding bits be helpful? As I said above, I sharpen all my bits by hand on a wheel (as it should be used, not on the side) with no gadgets. There's no magic, it's just understanding and practice. I had to learn when I started volunteering at a steam workshop where every single drill was blunt because there was nobody who could or would look after anything. I had an enormous stock of knackered MT drills and jobs I needed to do. The great thing about those large drills is they're easy to hold and take a lot of grinding so you can take your time to get a feel for it. Smaller drills (<1/4") are harder, but entirely possible with practice.

Half the battle is understanding how and why the geometry is created, then the other half is getting the motion and holding right. Drill sharpening has not seemed like black magic or a chore for many years (and I'm not even 40 yet)!
 
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