Anyone use a Drill Dr. or other drill bit sharpeners?

I'm looking at the one from Harbor Freight for about $20, the drill Dr. is about $100 and I could buy a lot of bits for that.

In the past, I've use a dremel with grinding bit and sharpened them that way, but I don't think it does a great job.

Would I be throwing away my $20 @ Harbor Freight?

 

There are old threads here with info on the drill doctor.

 

I have a DD750 and it works well. Its not so good for fixing damaged or poorly ground bits but does a wonderful job of fine tuning them and keeping them sharp. It gets the relief angles perfect and the point centered.

 

Sharpening drill bits by hand is one of the basic things I had to learn as a Tool & Die apprentice. I whish I had a Drill Doctor for bits smaller then ¼" but anything larger is easily done by hand. Although you will need a wide well dressed grinding wheel and a drill sharpening gage.

 

i too have the dd750, it is very easy to use and works very well. split points take some practice though. if your bits are chipped or broken it is best to get the rough shape on a bench grinder or a dremel, it is quicker and you dont wear down a $20 wheel. i think it is a very good investment and you could have a couple buddies go in with you to offset the $100+ cost.

 

I bought the $40 drill doctor that uses the small paper rolls and runs off a drill. It will not even touch my drill bits. I guess they are too hard and I should have bought something with a diamond wheel.

 

I got mine at homo repo for 75 or 80 plus tax recently

 

you can also by one that attaches to a bench grinder

 

Purchased 1 of the inferior drill sharpeners thru discount supplier in effort to save some money. Found the tool worthless. Now shopping for replacement. Looking at the brand " Drill Doctor" 750.

 

We got one at work, I love it. I was kinda skeptical of it at first, but it amazed me at how much better it makes the bits. Got me outta trouble when I toasted a few bits.

 

I bought one from Harbor Freight that grinds up to 3/8" drill bits. I hand grind the larger drills.

 

I got a cheap drill bit holder that attaches beside the grinder. Does not work too well. Glad I only lost 20 bucks.

 

Forgive the rookie question but how often do you have to sharpen a drill bit? I got an 8" bench grinder for Christmas and I guess I should learn how to do it.

 

The basic issues that will destroy a drill bit are incorrect speed, feed and lack of cutting oil. The Machinery's Hand Book and various sources on the internet will have charts to select the correct speed (rpm) for a given drill size and the work piece material. If you want to reduce the need to sharpen drill bits try to use them correctly. But this is not always possible if all you have is a 3/8" drill that turns 2,800 rpm. For ¼" and smaller bits with cutting oil this is fine but for 3/8" to ½" bits you should use something less then 1000 rpm. Anything over ½" should turn less then 750 rpm or you will just burn up the bit. Always use cutting oil. This will greatly increase the life of a sharp bit and it can allow you to turn a bit a little faster if there is no means to slow it down.

The above info is for cutting ferrous materials. The softer the material the faster you can turn the bit. If you're working a lot with alum, plastics or woods you can change the included angle of the bit (pointier) to be more effective when working with soft materials. Again just use cutting oil for metals.

But, eventually you will need to sharpen. If doing this by hand on a grinder always have a container of water close by to quench the bit in-between each pass with the wheel. You can just as easily burn a bit when sharpening it, which makes the cutting edges brittle. How do you know if the bit is dull? This is determined more by feel and performance. A brand new bit will cut fast and turn out nice chips. If you notice the cutting edges of the bit are rounded and you seem to be applying more effort then before then it is time to sharpen.

 

Thanks koconno2. Good information. I had no idea about the rpm range.