Sharpening Large Drill Bits

I have a Drill Dr that works great but need a 3/4” bit sharpened. I tried on my bench grinder. I’ve watched YouTube videos. I just can’t seem to make it work.

What’s the secret? What video am I missing?

 

If you need some entertainment ave has a video on doing it with an angle grinder and cutoff wheel.

 

Hold the cutting edge against the flat side of the wheel, at the proper angle.

Then as you grind, you kind of drop-and-rotate-up-and-out the lower end of the drill.

This creates the vital relief angle behind the cutting edge. Don't rotate too far, or you'll ruin the opposite edge.

Repeat equally on both edges. Generally speaking, close-enough will work okay.

Do not let the steel get blue hot, or you will have ruined the temper

 

Get a cup of water to dip your bit in to cool it.

 

Don't know what you're missing, but the fellow in the video below covers the bases/elements. Of course, he's practiced. A homemade jig may be a useful "crutch", but that's another video without the help of this fellow talking you through the fundamentals. He's taking for granted that you have a good wheel properly dressed.

 

I got it to cut!! Making a separate relief angle and measuring the cutting edge to be sure that they are even seemed to be the keys for me.

 

That was the video that helped most.

 

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That's a great video, Nick. I don't have a belt sander like that at home but, we have one at work. One of the older guys there was sharpening bits on the belt sander one morning and I asked him about it. He showed me how to do it and swore by it. I haven't put a bit on my bench grinder since that day. I take them in to work and put them on the belt sander. Can't wait to find a sander for the shop at home. I'm too cheap to buy a new one so, I keep waiting for a decent used one.