Thread: Sharpening twist drill bits freehand

in the last ten years, I've bought two drill doctors and could never get a good result with either. I think they're fiddly. other than that, I have used the grinder wheel (no rest involved) or a belt grinder contact wheel to hold a drill bit with both hands to rotate it through. I think the jig is going to make this take longer 0 it can be done totally by eye. The only concession with hand sharpening like this is no split point, but I use my bits a lot in metal now as well as wood. It's not an issue in wood, but in metal if the angle is too aggressive, a lot of non-cutting area is presented into steel, for example, at the start. But even that is solved easily by using a smaller bit to locate a first smaller hole. something like a 1/8" bit.

I will admit I didn't try screwing around with either drill doctor for too long and in total with both, haven't spent more than an hour trying to figure them out.
To sharpen a bit with no rest entirely freehand takes about 30 seconds at most. If everything looks good after initial strokes, it may only take ten seconds.

30 plus years ago I was a machinist. It was standard practice to hand sharpen twist drills. Since I got into woodworking I haven't found much need to sharpen them. I hear your timbers are pretty darn hard compared to what i normally drill. Now I wonder if I can still do it, been a long time but I think I still know what to look for. Outer points level with each other and the chisel point centered. Of course the lands or whatever they're called need to flow downward from the cutting edge. This was all done freehand by eye and doesn't take long to get the hang of if you start with larger bits.

When I started my apprenticeship (metal, not wood ), 43 years ago, we were all taught how to sharpen drill bits freehand on the grinder. I still do it the same way today, often to the amusement of the younger tradesmen, who were bought up to throw them away when blunt, and get a new one.
I often use the side of the grinding wheel, because the front of the wheel on workshop grinders has often been abused, and are rarely dressed flat. There is not much sideloading to the wheel when sharpening drill bits, as a light touch is all that’s needed.
I start with flute facing up, holding the cutting end with my left hand, and the non-business end with my right. Bring the bit in to the wheel at the correct angles, and grind until the full width of the cutting edge is freshened, then rotate my right hand down to grind the relief angle, then do the second cutting edge the same amount.
These days with my failing eyesight, I usually don’t do any smaller than 3mm (1/8”), but if there are no new bits in the small sizes, I will give it a go, if the grinding wheel is in good condition.
Practice a bit, getting the angles right, and you will be surprised how easy it really is.

Originally Posted by Ironwood

When I started my apprenticeship (metal, not wood ), 43 years ago, we were all taught how to sharpen drill bits freehand on the grinder. I still do it the same way today, often to the amusement of the younger tradesmen, who were bought up to throw them away when blunt, and get a new one.
I often use the side of the grinding wheel, because the front of the wheel on workshop grinders has often been abused, and are rarely dressed flat. There is not much sideloading to the wheel when sharpening drill bits, as a light touch is all that’s needed.
I start with flute facing up, holding the cutting end with my left hand, and the non-business end with my right. Bring the bit in to the wheel at the correct angles, and grind until the full width of the cutting edge is freshened, then rotate my right hand down to grind the relief angle, then do the second cutting edge the same amount.
These days with my failing eyesight, I usually don’t do any smaller than 3mm (1/8”), but if there are no new bits in the small sizes, I will give it a go, if the grinding wheel is in good condition.
Practice a bit, getting the angles right, and you will be surprised how easy it really is.

Brad

Discarded drills by young tradesmen is a good source of supply.

Until recently I had the same philosophy with the smaller twist bits, but I am now more inclined to give it a go. I use my headband magnifier, which was purchased for sharpening handsaws. It makes quite a few things possible for older eyes. Also, if I was going to ditch the drill anyway, I might as well try. It will either work or it won't. I don't think I have had any absolute failures.

Just on the sharpening angles, wood is much more tolerant and in fact a steeper angle is beneficial. Not so for steel which is more demanding. There are a variety of angles quoted as appropriate for metal, but I tend to stick with 135°. Having said that, I have never measured one yet. I go by eye as to whether it looks right. Years ago, when I was at Tech, they had a template that could be matched to the bit angle on one side and was most useful for checking the angles were equal. I have often reflected that I should make one up, but in reality I don't think I would use it or more likely, I would be unable to find it. A template is probably most useful for bits greater than ½", which will be used in metal. (Large twist bits don't work at all well in timber.)

Regards
Paul

One correction to make: the photos of grinding are reversed. (I took these photos a few weeks back, and lost the memory of what was happening at the sharp end).

Also, as noted, this is a jig to train the hand. You will discard it after the angle and rotation become familiar.

Regards from Perth

Derek

Originally Posted by Bushmiller

Brad

Discarded drills by young tradesmen is a good source of supply.


Regards
Paul

Definitely Paul, it wouldn’t take long to amass a large collection .
The industry I work in, is as much to blame as anything else. Drill bits are treated as consumables, and are free to grab from the toolstore as needed, it’s no wonder they don’t bother to learn to sharpen them when they are not having to buy them.
And as such, I have more drill bits than I will ever need in my lifetime.

I just reread my last post, and should add, that when I lower my right hand to grind the relief , I raise my left hand at the same time to create the sweep that grinds the relief angle, this is where the art comes in I suppose. Getting the correct starting angles is fairly easy once you know what they are.

If you are starting with a bit that is just blunt and not broken, using the side of the wheel, which you know is vertical, move the cutting edge in towards the wheel, and angle the bit to grind at the original factory ground angle, drop your right hand down a little , so that the bit is presented to the wheel with an approximate 5* relief, now gently push the drill bit onto the wheel and hold the same angles until the complete edge is refreshed, then drop your right hand and raise your left in a steady sweep to create the extra relief behind the cutting edge. You have to do all of this fairly quickly, as you don’t want to overheat the steel too much.

If your drill bit has the corner tips chipped, it’s best to grind in steps. Grind one side a little bit, then grind the other side the same amount. Then back to the first, keep going in small steps, grinding each side an equal amount, until the chipped corners are gone.
Its very important to grind each side the same amount, otherwise when you use the drill bit, it will be cutting on one side only. A properly sharpened drill bit will be ejecting equal swarf out of each flute when you are drilling. If it’s only cutting on one side, it won’t stay sharp for long at all, and it will sideload the drill bit, your holes will end up oversized.

Originally Posted by banjopicks

30 plus years ago I was a machinist. It was standard practice to hand sharpen twist drills. Since I got into woodworking I haven't found much need to sharpen them. I hear your timbers are pretty darn hard compared to what i normally drill. Now I wonder if I can still do it, been a long time but I think I still know what to look for. Outer points level with each other and the chisel point centered. Of course the lands or whatever they're called need to flow downward from the cutting edge. This was all done freehand by eye and doesn't take long to get the hang of if you start with larger bits.

Other than drilling up the endgrain of something like gombeira (twice as hard as hickory and nearing twice as dense), there isn't any wood that's much of a challenge beyond what you'd have in oak or maple.

Wood's not demanding to drill unless you manage to get the point way off center and create a wander. I'm far from what you were - a machinist, but for woodworkers always figured that for critical shallow cuts, stub bits would make a lot of sense in a drill press. 1/8th bits and such are problematic freehand if they wander, and also - especially - if drilling annealed metal parts for knives.

And then I saw an indian pocket knife maker (like india, not american indian) with a drill press and a tiny short bit and he as demonstrating exactly what I was thinking.

Sharpening completely freehand to "time" more or less is self correcting. I was forced to sharpen a bit this morning after dulling it drilling into a screw - and it was kind of four licks on each side. I've gotten in trouble before trying to do too much and then having to waste time correcting things to get the point centered. It reminds me of saw sharpening - if you get too wrapped up in trying to do more than keep a rhythm with a crosscut hand saw, the teeth could end up looking like anything. if the effort to cut each tooth is kept equal and things are minded to make sure the file is working equally, they stay the same size without other effort. Even if the second comment means learning to file off hand is needed to sharpen one of the sides of teeth - it doesn't take long to get the hang of and beats a screeching file.

Originally Posted by derekcohen

One correction to make: the photos of grinding are reversed. (I took these photos a few weeks back, and lost the memory of what was happening at the sharp end).

Also, as noted, this is a jig to train the hand. You will discard it after the angle and rotation become familiar.

Regards from Perth

Derek

I found that confusing and figured two were out of order. If the bit is rotated enough, though, you can actually create a motion where you are turning the flute near vertical instead of perpendicular, and you'll have to actually lift the bit.

I tried sharpening a bit with the stuff reversed in case I misinterpreted what you're saying and strangely enough, you can get results every bit as good free hand reversing the lift as long as the flute is turned further in the cut. I see no difference.

It's possible to split the point well on bigger bits using one of the CBN wheels with side grit, too, but it's not really worth the time to do it for regular work as a tiny error in overcut spoils the effort.

Originally Posted by Ironwood

Definitely Paul, it wouldn’t take long to amass a large collection .
The industry I work in, is as much to blame as anything else. Drill bits are treated as consumables, and are free to grab from the toolstore as needed, it’s no wonder they don’t bother to learn to sharpen them when they are not having to buy them.
And as such, I have more drill bits than I will ever need in my lifetime.

I just reread my last post, and should add, that when I lower my right hand to grind the relief , I raise my left hand at the same time to create the sweep that grinds the relief angle, this is where the art comes in I suppose. Getting the correct starting angles is fairly easy once you know what they are.

If you are starting with a bit that is just blunt and not broken, using the side of the wheel, which you know is vertical, move the cutting edge in towards the wheel, and angle the bit to grind at the original factory ground angle, drop your right hand down a little , so that the bit is presented to the wheel with an approximate 5* relief, now gently push the drill bit onto the wheel and hold the same angles until the complete edge is refreshed, then drop your right hand and raise your left in a steady sweep to create the extra relief behind the cutting edge. You have to do all of this fairly quickly, as you don’t want to overheat the steel too much.

If your drill bit has the corner tips chipped, it’s best to grind in steps. Grind one side a little bit, then grind the other side the same amount. Then back to the first, keep going in small steps, grinding each side an equal amount, until the chipped corners are gone.
Its very important to grind each side the same amount, otherwise when you use the drill bit, it will be cutting on one side only. A properly sharpened drill bit will be ejecting equal swarf out of each flute when you are drilling. If it’s only cutting on one side, it won’t stay sharp for long at all, and it will sideload the drill bit, your holes will end up oversized.

Not sure what you use - I used to buy cheapest and discard when needed - occasionally buying plus imports like irwin imported or something and then regretting spending the extra amount - if you get often used import bits in sets of ten here, especially for wood, it's still an economical proposition.

And then at one point strugging to find a christmas gift, I went to a tool store in amish country and bought a marked down set of viking norseman or whatever brand they were using on them - US made bits. They were sharp all over like a fine knife. Even if I resharpen them and don't split the point, they work better than import bits, and both in metal and wood, much longer. they are not cheap, but there are much more expensive drills - a jobber set of HSS bits is something like $120 with tax here, 29 bits. they are the first bits I've ever had where I get upset with myself if losing track of one in the shop. I haven't bought an import bit since then because despite drilling enormous amounts of metal, I haven't had to replace a bit. In the end, they will be cheaper, but not at the outset - as well as they work and as well as they're finished from the factory, I wouldn't care.

At some point, the obnoxious trend of private equity and venture capital buying every small business here will ruin those bits by increasing the price and decreasing the quality, but as of yet, it hasn't happened. There's an unfortunate wave of cheap money that's taken over just about everything small business by appealing to greed of the ownership group - from veterinary practices to small toolmakers and retailers. Everyone but the original owner and the private equity fund loses.

It's a character flaw, I know, but sharpening drill bits freehand is something I have never truly mastered. My fitter uncle showed me how to do it (on the side of the wheel) close to 60 years ago, but I have only sharpened bits at long & intermittent intervals & never gotten really good at it like he was - the darn things were always perfect and to whatever angle the job demanded. I have long since given up trying to re-sharpen anything less than 2mm, it's definitely far more economical for me in time & saves gastric rubor to replace such small bits. Larger sizes are far too expensive for me to replace when dull, and easier to re-sharpen if they are touched-up as soon as they dull. Some days, I can do a pretty fair job of it but on a bad day I end up chewing away a lot of useful metal before I can get the end looking anything like symmetrical.

But I console myself that it's a lot like sharpening saws (at which I'm a little better!); both work far better than completely dull ones, even if the sharpening is a little less than perfect...

Cheers,

I love my drill doctor. There's a specific trick to getting them to work right - but that's all right there in the instructions. It takes ~30 seconds to sharpen and off you go. Super handy when you're doing metal projects and dull several bits in the process.

I used to save up used, cast off bits from work and resharpen them. They were all good quality stuff. I don't bother now, as I have plenty.

I was at work the other day, and had to drill out some broken bolts. I have a fairly new set of left hand drill bits that I got specifically for getting out broken bolts, I bluntened the 4mm bit I was using, so had to take it to the grinder. I had never sharpened a left hand bit before, so was wondering how I would go, it felt a bit foreign freehanding it, but cut as good as new again once I freshened it up.
I had to sharpen a 5/16” straight flute solid carbide bit on the same day, I got it sharp, but couldn’t put a split point back on it due to the well abused wheel on the grinder. It worked ok when there was a pilot hole already drilled through the bolt. The carbide bits really need the split point, because the flutes are so shallow.