Sharpening a drill bit
Well Ill try to explain it, but its more or less somethign you need to see. Once you get the hang of it, it isnt to difficult.
First thing you need to know, is that its done on a grinder, but I think you already knew that. For our purposes, lets assume were sharpening a 118 degree standard bit. Its best to start out with a bit abotu 1/4 inch, and dont usea good one. I you have a HF near you, pick up a couple.
First, you need to mark a 59 degree line on your tool rest. (this can be done by using a brand new 118 degree drill bit as a guide, and placing one cutting edge flush with the grinding wheel, then marking your line) It shoudl be 59 degrees from the face of the wheel, and, if you are lookign head on, it traves to your left from the center of the wheel out. Next, you are going to want to stand in line with this line. grab the shank of the drill with your right hand, and place your index finger on the tool rest, then place the bit on your index finger, and hold it like that. angle the shank up about 10 degrees, and place the cutting edge against the grinder, and slowly lower the shank. Your hand will make a natural arc that creates the lip clearance needed to allow the bit to cut.
its kind of hard to explain
Twist the bit and do it again on the other edge. Make sure you don get it too hot, becuase it is like a chisel... once its blue its done. Usualy, Ill make one pass on each cuttign edge, then dip it in ice water. Its not hot enough to temper it or anything, but it cools the steel down a little faster. Also, you need to make sure that you are grinding the edges evenly, otherwise, when you try to drill a hole it will be all oblong and stuff because the cutting edges are not equal. A drill point gauge is very helpful in making sure you have the angles right. Start off wiht a reall cheap HF bit, and go through the motions with the grinder off. Make sure that you mantain full contact all the way across the bit whill doing this too. Once you feel you have gotten fairly decent at it, try "shortening" the bit. by grinding the the bit down, without changing any angles. Check your progress with ad rill point gauge. Then, once you feel your good at this, sharpen the bit flat and try to make your own point. It will tkae quite a bit of practice, anda few bits but you will get it. Also, If you could get a piece of 1/4 aluminum. All you need is a little 4x4 square. You are going to want to drill a hole in it after you think you have sharpened the bit sucessfully, to see if it is cutting unusually, or off center.
For a 135 degree bit, mark a line that is 67-68 degrees. A split point can be made by using the edge of the grinding wheel.
Good luck and dont give up!
Jim
