Low Profile Chuck for Carving Corzetti Stamp Blanks by icenyne

Last crawled date: 3 years ago

Having been holed up for much of 2020, I ended up making homemade pasta of various types. One interesting and somewhat unknown form is corzetti, embossed coins of pasta originating in Liguria in the middle ages. (see https://en.wikipedia.org/wiki/Corzetti) The stamps are carved from wooden dowels about 2 inches in diameter.
Commercial corzetti stamp sets are not inexpensive, particularly ones carved with custom designs. The appeal of making personalized and themed corzetti for friends and family was too great to settle for the few (even custom) designs available, so I had to make my own stamps, which easily justified the purchase of a 3018 CNC machine. The goal was to make Christmas gifts for family and friends by the end of year... (The goal was reached, I made about a dozen sets, but this thing is about continuing to make them and make them more easily.)
I started inexpensively with 2" diameter disks from Amazon carved on the CNC. These worked great but they lack the integrated cutter of the traditional corzetti stamps and a nice handle. So, I needed to use 2" diameter dowel for starting blanks. (This prompted getting the Shopsmith ER10 I'd picked up 4 years ago running, but that's another whole story...)
The 3018 CNC only has 40mm of vertical travel. The corzetti stamp pieces end up being about 2-3 inches tall, so how do you face the ends and then carve them in a travel space that small? Simply: you change out the bed on the CNC for a wood one (using the CNC itself to cut the bearing and nut holes, of course). The new bed has a hole to accommodate the dowel and a 3D printed jig to hold it in place while faced and carved.
Unfortunately, variations in blank diameter require re-centering the bit nearly every time and the jigs don't hold the blank's square to the CNC bit very well, even after 4 iterations of jigs (pic of latest pip vise inspired clamp is attached)...
Having seen self-centering chucks and collets on Thingiverse, I really wanted something for holding the corzetti blanks. Collets were out because my lathe skills yield too much variation in diameter; PLA is not all that flexible. So, it had to be a chuck, hence this remix of these two things:https://www.thingiverse.com/thing:624625 for generating the scrollhttps://www.thingiverse.com/thing:2670620 for jaws and jaw guides
Finally got a working faceplate.
Still a work in progress but I have a working chuck, so work on this has stopped.
STL files came from: https://www.tinkercad.com/things/3Gy7omUSfS6
Update 23/02//2021: After trying to carve some disks, it became apparent that the jaws were too short: they were bowing up in the center and would not hold the 6mm thick wood disks I have very well. I lengthened the jaws and it seems to hold much more firmly since all the scroll teeth are engaged and the jaws occupy the full length of the guides in the faceplate. It's still a pain to hold the disk while tightening the chuck, so the jaws may be updated later...