r/metalworking • u/justnotright3 • 8d ago
Sharpening drill bits
So I have several pilot bits for my hole saws I use to cut cirlce blanks. They are running around $10 us a peace. They do hold up a lot longer than the other bits I can get at the big box stores. Atleast 3 times as long. They are the demon brand and I use anchor lube on the bit as well as the hole saw while using in a drill press. I have a drill Dr but it does not bring the drill bit back for long.
Are there other good ways to sharpen a drill bit. I have been told to sharpen them on a bench grinder but my hands shake alot when trying to grind them. Are there any jigs to try? I have a tormek but hate spending 400 dollars for their jig.
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u/NoPantsTom 8d ago
I actually have one of those General jigs and I love it. You clamp the bit in, theres a little protractor to tilt the angle, and it swivels after you lock the drill in. I have it on the side of my grinder due to space but you can bracket it to the front as well. I make the "split" back angle by hand afterward, but that's really just touching the bit to the corner of the grinding stone with the other side hanging off lol
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u/HellMuttz 8d ago
What size drill? What material? how many holes are you getting per drill? If you're using a drill press are you sure you even need a pilot?
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u/justnotright3 8d ago
Drill is 1/4 and I need the hole for assembly. The metal is 16 gauge mild steel backed by 1/2 OSB. and out of the Diablo drills, getting about 150 holes before performance starts to drop off. I have not tried some of the life-time warranty drill bits yet, but that may be coming. I have trippled the number of cuts with anchor lube. Might due better with tap magic but the wife could not stand the smell and made me double wash any clothes I was wearing.
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u/HellMuttz 8d ago
150 holes of 15 gauge steel is only about 9 inches of material removal which is abysmal even for a cheap drill. I'd investigate why you're getting such awful tool life before anything. What RPM are you running?
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u/justnotright3 8d ago
I am at 900. Lowest the drill press will go
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u/HellMuttz 8d ago
That should be fine, probably about half of what the drill wants but I can't imagine you want to go much faster with a hole saw. What does "performance starts to drop off" mean?
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u/justnotright3 8d ago
The pilot starts taking longer to cut into the steel, and the shavings start looking a lot different.
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u/HellMuttz 7d ago
It's an interesting situation, If its not blowing out the OSB than its really just dulling at the tip. If your work flow allows you may try a spot drill first. You could also try just touching up the tip with a diamond file. But if it comes down to it I'd just source cheaper quality drills, Haas sells coated 1/4 stub drills for $2.8
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u/frankiebrown1988 8d ago
A simple drill-bit sharpening jig that clamps the bit and controls the two angles may be worth trying if hand control is difficult; a V-block or guided fixture can make repeatable positioning easier than freehand grinding. Before buying one, check that it supports the pilot-bit diameters and point geometry you use.
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u/IsuzuTrooper 8d ago
do it by eye. practice makes perfect. unless it doesn't. like with drill bits sometimes :/
I can get it sharper 90% of the time. just always have a water spray bottle. heat dulls bits. on the workpiece and bit itself
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u/RedneckSasquatch69 6d ago
Learn to do it by hand. Like any skill, you suck at it until you don't. So go get good
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u/Alone-Programmer-683 7d ago
I think you should make this a two step process. When I want to drill out anything with a hole saw and keep at all to the correct size, I drill the 1/4 pilot hole with a regular twist drill. Then install a piece of 1/4 drill rod in the hole saw mandrel.
Here is the critical part. Don't use the dogs in the mandrel to hold the hole saw. They don't hold it firmly and it wanders all over the place. Put a little anti-seize on the mandrel threads and tighten the hole saw down on the mandrel face. A much smother, easier cut for everything.
The hole saw will come off the mandrel when you need to do so. Lock the mandrel in your vise and gently put a pipe wrench on the hole saw. It will move.
The drill rod will not wallow out the pilot hole like the twist drill will and the hole saw will cut much easier and last long, plus making much more accurate cuts.
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u/Necalmed 6d ago
Honestly it just takes a little practice. Get a bunch of broken/dull bits and put a hard disk on your 4" grinder and do your best to put around a 30° angle on them( if the bit isn't broke your just touching up the existing angle. You kinda just lightly touch it, roll 180° and touch again. See it you can drill into some 1/4" mild steel. Honestly in about 4-5 hours of practice you should be pretty competent. Millwright/welder by trade here
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u/kitesurfr 8d ago
It's totally worth just investing in a Drill Doctor
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u/Rude_Meet2799 8d ago
See OP’s statement about Drill Doctor. He has one already tried it
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u/justnotright3 8d ago
I am ordering new diamond wheels for it
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u/Rude_Meet2799 7d ago
I have not heard much good about them.
I was taught how to sharpen by hang, 1/4” and bigger.
I found some really thin grinding wheels, which are great for splitting points so that lives on the other side of the grinder.
I always use the white or pink aluminum oxide wheels, the common gray ones are too rough
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u/donitosforeveryone 7d ago
Jeebus. Go to Amazon and buy a Drill Doctor. They do a great job, work quickly and sharpen up to like a half inch bit. Anyone who uses drills, should own one
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u/Monkey_Sox 8d ago
Go to YouTube. Find the sharpening video by Watch Wes Work.