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John at the homecoming asked me to do a seminar on how to sharpen drill bits.
With the cooking and all the other activities going on, we did not get a chance to do that.
But I have come across a how-to video that will show you how, on a belt sander.
You can also sharpen them on a bench grinder the same way.


Hope this helps!
Don

Here's another drill sharpening video with more technical info and humor.

Good video Grigg III.
I really liked the humor and how he explained how a drill works.
Of course there are some more tricks for different types of material.
Speeds, feeds and lube are also a big factors.
But for most of us, it gives a better understanding, of how a drill works.

Wonder if this should be moved to the tool threads?
Don

Thanks guys. I learned something today.

Thanks Don! This is good info -- Good idea about moving it to the tools forum.

I have a friend who is an expert at sharpening with a belt sander. My dad did a decent job with a grinder. My hands shake too much, so I use a Drill Doctor. Used properly it does an excellent job.

I agree Fred. I use my drill doctor all the time. sure beats fighting a dull bit!

Once the bit is sharpened, it stays that way a lot longer if it's lubed well. I like to use non-salted lard, mixed with a little Diesel fuel or Kerosene as a drilling lube. On those slow, heavy cuts, it smells a lot like bacon frying! Most people run drills too fast, too dry, and don't put enough down pressure on the bit. At the right RPM and down pressure, a sharp bit will roll a continuous tight spiral of cuttings out of the hole. If you let the bit "skate" without making chips, it will overheat and dull itself in a hurry.
Jerry

It's amazing how many of those beautiful drilling and tapping cans of oil I have around the shop. I say beautiful because they go un-touched by most of the guys. My can look pretty well used, though.

When i worked at Naval Weapons Station, Concord, the machinist gave me a Plews Oiler with Trans fluid and Diesel that he used for cutting oil.
Still have that, and still use it.

Yes, speed is everything when it come to drilling. Our drill press has 12 speeds but often there is nothing that is correct for the material being drilled so we then use the mill with infinitely variable speed. With the right speed most everything can be drilled with a HSS drill with no need for cobalt or carbide. Have drilled through leaf springs and spring steel bumpers without a problem. Usually use the old sulfur base cutting fluid for small jobs or hook up the fluid pump for big jobs. The fluid in the pump reservoir takes a cup of concentrate to a gallon of water and is much easier to clean up than oil base fluids.

Decades ago when I took a machining class at a local high school I was taught what I thought was the simplest drill sharpening method that could possible exist, way simpler than any other I've ever seen. Then along came this video that demonstrates an even simpler method:



I haven't tried it yet but I intend to. It seems like it requires no skill at all, just some dull drill bits and a bench grinder.

I have a drawer full of dull bits. I need to watch this and get to work.

I mostly use Ridge black or clear cutting oil my dad (gone54 yrs now)said that black oil has sulfur in it makes the tool wanna cut ! on slow rpm like drilling leaf spring holes i think he was right ! also on stainless Ridge clear cutting oil is all that will work says right on the jug for black pipe or stainless steel pipe with their dies made s.s. nipples for burial work...will last a looong time ! some of those specials work fine too !

I have a Black & Decker drill sharpener back when B&D made good products (1960's). It has two adjustable rails and is powered by a very old but good Millwaukee 3/8's drill. it was my dads. It has an angle setting which I'm pretty sure I set at 45 degrees. I only sharpened a cheep set of Chinese bits that were given to me as a gift. Completely useless on many levels. I agree I set them on the wrong angle. The new ones will start to cut but even on a slow speed and diamond cutting oil they will break off. Solution the trash recycle bin has a full set. Now I know how to sharpen a 1906-1907 complete set that a machinist that worked for Stanly Steamer gave me about 40 years ago in two solid oak chests along with huge & long bits. I have only used a few of them and they cut like a laser, well almost. My question is are different larger sizes of bits sharpened at a different angle? Thank you yar for the U tube lesson. Doc

The angle should be 30 degrees on a conventional grind. I’ve sharpened thousand of bits by hand during my career as a machinist and the video is spot on. The problem arose when we needed a hole to be exact. Getting the point in the exact center Is difficult by hand and can really be accomplished consistently by a dedicated drill grinder. If the point is off center, it will cut a larger hole. The other issue is grinding very small bits such as 1/16” and smaller. Also try resharpening a drill that you snapped off a half inch or so. Very difficult to re-establish the proper geometry by eye. We in the shop bought a dedicated drill grinder and once set-up properly made sharpening exact and very easy. I found an old General drill grinding attachment at a yard sale years back and use it on my bench grinder.

A note on cutting fluids. Early in my career we used “Cutting Fluid” which was petroleum based by the gallons. This stuff worked great on any milling, drilling or lathe operation, but smoked like crazy, and was difficult to clean up the machines after. In the eighty’s we started using both water soluble coolant on our larger drilling operations and 16 oz. cans of Rapid-tap on the smaller drill presses. The advantage to the water soluble coolants was it didn’t make a mess, cleanup was minimal and the fumes were tolerable. Imaging flooding a 3” drill bit with gallons of oil based coolant? Cleanup would be a job in itself not to mention the all of smoke coming off of the bit. It does not lubricate as well as an oil based coolant/lubricant but with larger machining operations it did the trick. The advantage to Rapid-tap and similar products is in addition to a lubricant they also contained a coolant that evaporated very quickly keeping the bit cool.

Just my two cents!

On the south bend lathe I always use Ridgid dark cutting oil on my taper shank bits. They mostly come out of the work looking just like they did going in. If you note which cutting edge turns out the heaviest shaving you can knock it down a little to get an even cut and a round and accurate diameter. Most of these bits are 60 years old. On smaller bits the nitrided black ones seem best ! the old machinist would sharpen the big ones by measuring with a pocket scale he always carried !

This is what I used to sharpen drill bits. I kept mine in my tool box.

I have also always hand sharpened drill bit and used a drill gage similar to what Phil shows in his picture.

Don

The 8" bench grinder I just bought at my local pawn/gun shop for a fraction of what it cost new has a V-shaped slot in the rest in front of one wheel that's the proper angle for drill bit sharpening. It works great!
Jerry

Ditto to da drill doctor. I have a ton of bits. Ill wait till i see more dull than sharp. Downtime chore for sure, but nuttins worse than trying to force a dull bit.

I just spent a few hours a week or so back sharpening my bits. All of them. What a pain, tedious, ugh... I hated it.

Until I had to drill some holes.


Ahhhhhhh! Satisfaction guaranteed!

Whatever the angle between the cutting flutes is, it's important that both flutes cut evenly. Otherwise the frill tends to "walk" in one direction as the hole progresses, and the other cutting edge is just along for the ride- - - -it's not doing much cutting. Normally the included angle between the flutes is 110 degrees- - - -55 degrees per side. Soft material such as aluminum can use a sharper angle, and hard stuff such as annealed tool steel needs a flatter cutting angle, a lower speed, and lots of coolant.
Jerry

Been sharpening my bits like this for 30-35 years, my buddy has a drill doctor mine cut better, faster, longer!
Sometimes I get em a little greedy but I like em greedy!

Those of you who use/own a Drill Doctor, which model do you use?

Thanks

Tim, My unit is a 750X, purchased for its flexibility in chisel angle and larger chuck (the 3/4" chuck is available as an option in the 500 and XP models, but adding it runs the price up to about the same as the 750X). Shop a bit, and they can be found for less than list price.

Doug

$159 is the list price for the 750X and it is the price of almost all sellers.

Except $99 at Home Depot and $129 on eBay.

Home Depot

This 750X looks like the Home Depot product?
750x

If bits are not sharpened evenly they will drill oversize. The longer flute will act like a boring bar and the shorter flute will do little to no cutting. In a lot of instances it might not matter, but if drilling a hole to tapped it could result with inadequate threads.

John

The one i have is actually da cheap one. Looking at pics, i think it da 350x. It was an Xmas gift maybe ten years ago or better. It takes patience and follow directions. But works good. Especially for a novice. And and previously stated. Even is also key to a good sharpened bit.

If you want a truly round, exact size hole, don't use a drill bit. I drill those kinds of holes a few thousandths undersize, and finish up with a chucking reamer. Having a bunch of flutes in a complete circle instead of two cutting edges keeps the hole round and the right size, especially if you're using a drill press or the tailstock on a lathe to hold the bit.
Jerry

If you don't have the fancy tool rests on your bench grinder, tack weld two 1/2" nuts together (flat to flat ) and you have a drill bit sharping guide. Put the bit into the v and and you can see any flaws in your bit and the angle is about right.

I have worked for Lockheed Martin for some 50 yrs. and have drilled a few holes myself. We use a product called Boelube to keep our drilling from dulling of corse you bolters would cry if you knew what we did with most of our dulled out drills
. Basically Boelube comes in liquid form a paste etc. etc. We generally use push tube White and the 12oz. Blue. I believe you can buy it on Amazon
. Back in the early early days when I worked on the SR-71 we used Bees wax believe or not. It had already been mentioned but the harder the metal the more pressure and less RPM.