End Work: There are a few options when it comes to mill work (off center holes, slots and so forth) on the ends of long rectangular parts or round shafts. Some choices are 1) horizontal milling machine 2) right angle head 3) vee blocks 4) angle plates 5) machined soft jaws in a vise 6) collet closing fixture 7) turning a machine vise on its side 8) tumble fixture (more about this in an upcoming CNC quick hits) 9) hanging parts off the front or back edge of the mill table. 10) The one I really like for round work is mounting a 3 jaw chuck on the mill table. Sometimes I have to mount the chuck on large parallels or 1 2 3 blocks to gain height or to blow out chips, but this is a very rigid setup that is repeatable and quick acting.

Eccentric Clamps: If you’ve got a machining operation that requires the use of low profile edge clamps, you’ve got some options (toe clamps, fixture clamps, uniforce clamps and more) all of which are available at www.miteebite.com. However, if you are in a jam for time and/or money, you can easily make your own eccentric fixture clamps. Here are the basics: starting with a tooling plate held in a vise or bolted to the mill table, establish a datum in either x or y using two dowel pins in one axis and a third in the other axis acting as a stop. Now, we need to machine an eccentric. Let’s say the part to be machined is aluminum that is 4” x 2” x ˝” thick with light milling. This would require two 3/8" eccentrics with .030” offset. To make the eccentrics, drill and tap a 3/8-16 hole in a piece round stock offsetting the hole by .015” from center. Thread a 3/8-16 socket head cap screw into the round stock and tighten it. Chuck the round stock in a lathe and cut the head of the screw until it cleans up. You can also do this op. in a 4-jaw chuck to achieve any offset you want. These screws are hard (about mid 50’s on the Rockwell C scale) so they will have to be cut with carbide. With a little bit of shop math, you should be able to determine where to drill and tap your tooling plate for the 3/8-16 eccentrics. These little clamps work better than you might expect. They not only push the part against the pins but they also lock and cinch the part down.

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