Mounting a 3-jaw chuck to your CNC
Often, a 3-jaw chuck is the best way to hold your work but it takes up valuable space and might possibly interfere with other things. Rather than setting up the chuck in a random location & having to tram it to find center every time, I came up with this simple solution. It makes removing & replacing a 4" diameter 3-jaw chuck in a repeatable location quite easy. By cutting a shallow groove in an unused corner of your board, you establish a consistent location for the chuck that can be set up as a saved work station in Mach3.
The most difficult part of the job is probably disassembling and reassembling the chuck. Of course, you should do this now and then as part of routine maintenance. I used a parting tool to cut the shallow groove that will provide a clamping surface. You will have to make a set of clamps, drill & tap for the clamps and provide suitable hardware.
As long as you make sure everything is clean when you install the chuck for use, the work station coordinates should be pretty accurate for most work. If anything, you might have to tweak X or Y by a thou or two. In fact, the repeatability of your 3-jaw chuck itself will likely be the greatest source of location error.
