Teach me about drill bit sharpening

[TechnoViking]

I have a bunch of old bits from various places. Many of them are dull. I'm wondering if it's worth it to try and sharpen them.

There are several styles of sharpeners out there. Ones that look like a pencil sharpener, and ones that are basically a jig that holds the bit in your desktop grinder.

I heard that once the bits become hot, from use or grinding, they are ruined. So should I try to sharpen them or just throw them out?

Thx,

[DRONE]

If they are just dull with no big chips on the cutting surface by it is fairly easy to sharpen them by hand using a bench top grinder.
start with the largest drills first, with the cutting edge perpindicular to the stone and follow the old grind

AutoSpeed - Sharpening Drill Bits

[URY914]

My Drill Doctor is one of the best things I ever bought for my shop.

[herr_oberst]

^^^ +1

[pete3799]

+ 1 on the Drill Doctor

[gwmac]

Drill Doctor, or
check out MRPETE222 on you tube, he has several videos about drill bits plus machining, casting and a ton of other shop topics

[RWebb]

1. the angle is different for metal than for wood

2. don't draw the temper

[1990C4S]

Originally Posted by URY914

My Drill Doctor is one of the best things I ever bought for my shop.

Which model?

[Bob Kontak]

Originally Posted by 1990C4S

Which model?

Same here. I am looking at the $60 one but you can spend way more on a Drill Doctor. I just have standard fare drills up to 1/2. A few over that with smaller shanks for wood.

Would this one fly for a DIY guy? My drills are sofa king pathetic. Must have 100 of them. Like two work that I stole from the shop in my machinist days......in the 70's.

https://www.amazon.com/Drill-Doctor-Sharpener-Engineered-Versatility/dp/B000BKX9CU/ref=sr_1_3?crid=3MKBKOEAT58CJ&dchild=1&keywords=drill+doctor&qid=1607554537&sprefix=drill+doctor%2Caps%2C442&sr=8-3

[URY914]

Sorry I'd see this reply.

I have the $60 model. Works wonders for what I need.

[matthewb0051]

My sharpening method is get in car and go to hardware store for a new bit.

This is enlightening!

[Bob Kontak]

Originally Posted by URY914

Sorry I'd see this reply.

I have the $60 model. Works wonders for what I need.

Sweet. I'm going to send that link to my daughter. No subject. No text. Just do a little Christmas fishing.

[908/930]

Most drill bits are made from high speed steel, they can get quite hot and not have a problem, not quite red hot.

Very easy by hand with a reg pedestal grinder, at least for bits larger than 1/8 or so, smaller can be done but really good eye site req. The point the bit can be smaller angle 60 deg for soft metals, and flatter 118 deg for general metals, for grinding all you are doing other then producing an edge is to relieve the metal behind the edge, too flat and you get more friction, too relieved and the edge is weak. Try to keep the cutting surface lengths the same length, unless you need the bit to cut oversize then you can make one longer, just rest the bit on your finger near the wheel, bit cutting edge facing up and horizontal gently push into the wheel while moving the back of the drill bit down with your other hand, start with a 1/4 to 3/8 bit so you can see what you have created.

For soft materials and plastics you can grind the face of the drill bit flat or negative angle, keeps the bit from corkscrewing into the material.

[Bob Kontak]

Originally Posted by 908/930

Very easy by hand with a reg pedestal grinder

I struggle with smaller bits. Sometimes I hit it right, sometimes I don't.

matthewb0051 mentions going to the store and buying a new one. I did that yesterday and sprung six big ones for a Dewalt 1/4 drill bit. It cut through the center of the hard, broken off exhaust bolt with relative ease.

I'm done with by hand. I use a drill once a month and it's usually in some God awful, horrid situation.

[wdfifteen]

https://forums.pelicanparts.com/off-topic-discussions/1012570-finally-getting-organized-here-2.html

Got to post 25 for my experiences with Drill Doctor. It's OK if you have a lot of drills. The best job of drill sharpening I've ever seen was done on a vertical belt grinder.

[Bill Douglas]

I've never sharpened a drill in my life.

But I'm guess in the case of high speed steel drills; you would only want to take 50 or 100 microns off?

I have a whole lot of good quality drill bits that could do with a freshen up. I also just tend to buy new ones.

[peppy]

+1 on the drill DR.
The best thing I have done for drilling metal is step bits. I've had a set for 15 years and I still use them on a regular basis, they are a bit dull but you can put a lot or pressure on one,

[Bob Kontak]

Originally Posted by Bill Douglas

I've never sharpened a drill in my life.

But I'm guess in the case of high speed steel drills; you would only want to take 50 or 100 microns off?

I have a whole lot of good quality drill bits that could do with a freshen up. I also just tend to buy new ones.

Sometimes you have to grind it 1/2 inch or more shorter if the flutes have been chewed up.

Then you start from scratch and best to thin the web. I wish I had a really thin wheel for that.

[Por_sha911]

There are titanium coated bits, carbon steel bits, hardened steel bits. Does one machine handle all those different metals?
The $60 drill doc "sharpens standard drill bits".

[908/930]

With HSS drill bits you can sharpen down until there is no flute left, as you get closer to the bottom the web gets thicker, no big deal just grind it thinner. Really a couple of degrees of clearance behind the cutting edge is all that is needed. Many years as a machinist when younger, working with stainless steel, really tough on tooling.