Reply To: Lathe collets…

[david pierce]

Tmac,
If you do not already have them you will need some tool bits. Look in the ENCO catalog (you should be able to pull it up online) and look at part number 383-5208 and 383-5212. These are 1/8 and 3/16 square 10% cobalt tool bits. You will need a bench grinder to sharpen them but you can pick up a good grinder from Harbor Freight for a small amount of money. The basic idea in sharpening tool bits is to have clearance angles where the cutter contacts the part being turned. The angles will be on the face, side and top of the cutter and are generally 5 to 10 degrees. Bob shows some cutters in his learn to turn video. There are probably numerous Youtube videos on sharpening lathe tool bits but I have not checked yet. In general, the steeper the angle, the sharper the cutter and less cutting force is required. Unfortunately, this makes the cutter weaker and more likely to wear and or break. The goal is to reach a comprimise of sharpness and strength. Make sure you have a cup of water next to the grinder to cool the tool bit off when you are grinding it. Grinding the bit will also heat up your fingers so dunk the bit into the water often.
Once the bit is sharpened, the tip of the cutter must be put on center. This is easy with the quick change holder as the cutter can be raised and lowered with the adjusting screw to line the tip of the cutter with a center in the headstock or tailstock.
david