Pie Jaws: These are excellent lathe workholding tools, however, if the parts to be turned are irregular (castings) or if you are running multiple parts and they vary in diameter, we instantly have a problem with making 3 point contact. The solution is to relieve all three jaws in the middle of the 120° pie. This will create a six point contact as opposed to a three point contact. In essence you have turned your three jaw chuck into a six jaw chuck. When you try this, you will achieve much greater flatness while reducing chatter problems.

Holding Round Parts In A Vise: When I have mill work to do on the end of round parts, many times I will use a 90° vee-block standing on end in the vise. This creates many problems. Number one is the 90° angle of the vee-block limits the size of the round part I can put in the vise. Number two if I have to use a small vee-block, the vee-block can fall between the bed rails of the vise. Number three if I have a large part to work on, the vee-block takes up more space than the vise will allow. To remedy this situation, I have made a special vee-block with a 120° vee. See photo below: This one has been machined out of a piece of aluminum that is 1.25" x 2" x 6". The vee doesn't have to be machined, it can be saw cut. You can make these out of steel, aluminum or even plastic and they don't necessarily need to be 2" tall. I have also made some with the vee splayed out to 150°. They work great.

Multiple Parts in a vise: If you have ever tried to machine multiple parts that are the same thickness in a vise, you will know that it doesn't always work. A simple fix is to put a piece of double back tape (two-sided tape or carpet tape) on the movable jaw of the vise. Trim the tape to the top of the jaw and apply a piece of thin cardboard (back of a note pad works) to the part of the tape facing the opening of the vise. This will take up any variation (up to .002") in the parts to be machined. If you have parts that are matched closer to (.0005" or less) you can use masking tape on the movable jaw of the vise. Keep in mind, if you are using coolant, this set-up will not last very long.

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