Gridfinity Holder for Criterion Tenth-Setting Boring Head (R8)

I'm not really expecting to get many (or maybe any) downloads of this, but maybe somebody else will find it useful.  Being relatively new to machining, I bought this boring head off ebay.  When it arrived, I realized that it wasn't the standard unit, but rather it has a device between the head and the shank which allows adjustment in increments of .0001".  I don't expect to ever make use of that feature given how worn my clapped-out Bridgeport is, and my relative lack of machining skill, but it's definitely interesting.  I wanted to change out the shank for an R8 one anyway (it came with a straight shank), so I actually tried to remove the tenths setting device briefly, but it wouldn't budge and I didn't want to break anything, so I'm stuck with it on there.

So yeah, there's probably not a lot of these boring heads out there, but here's a tray to fit them, if you have the same R8 shank installed on yours as I do.  There was a bunch of wasted space alongside the shank, so I added recesses for a couple of 3/8" boring bars of different lengths.

Like my other Gridfinity models, the base is altered to accept 6x3 magnets as a press fit, with the upper surface of the magnet holes modified to make the slicer bridge across correctly for a clean result.  Due to the size of this model, I have included sacrificial “mouse ears” in the CAD to give the ends more surface area to help prevent them warping off the bed.  These will need to be removed after printing.

The unit in the pictures was printed out of Overture matte red PLA on my Bear upgraded Mk3S+, using a 0.6mm Revo nozzle at 0.3mm layer height, 2 perimeters, and 15% infill.