This is a 3 part print that can convert an existing metal tamper base (i'm using a reg barber base) into a precision palm tamper. It works by locking in a depth gauge with the screw on cap to hit the edge of the basket at a certain depth. This will ensure you have consistent tamp pressure every single time. This is further benefited from a distributor set to a depth that is slightly less than the tamper gauge.

The bottom of the bolt adapter is configured to screw into a 3/8"-16 threaded hole (standard tamper base size) and the top of the bolt adapter is threaded to allow a tamper handle to screw into it. Be careful tightening these, as the metal threading will easily outweigh the tensilary strength of the printed plastic (you can wind up with broken off threaded plastic in your base, it's very hard to remove that). The top also features a 5mm hex slot to help loosening the bolts (again, be careful only tighten to mild resistance). The outer threading of the adapter bottom is M25-1.5, it allows the depth gauge and cap to screw on and lock in the depth. Print this adapter with the smaller threading pointing up.

The depth gauge should be printed with the smaller diameter surface (the top) on the print bed, the outer angle should not require any supports. Screw the depth gauge onto the adapter until the depth between the tamper base and the bottom is your desired depth.

The cap should be printed with the threading open (the large flat surface on the print bed). Once you have your depth gauge at the desired depth simply hand tighten the cap to “lock in” the depth. You don't need it to be very tight, just enough to prevent the gauge from moving. I am using a metal cap in the images as I cannibalized an old distributor to re-use this cap (which is where the M25-1.5 came from), but the plastic cap should work just as well.

Altogether, this system produce extremely consistent tamping. I suggest figuring out what your group head screen depth is first, then add 1-2 mm. 

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