That's really cool. Not really sure how feasible it would be to add this, but I once used a tamper that had a similar design but gave a little click when you reached a certain pressure - was good for consistency.
That’s great, I can definitely see the appeal of the project. The easiest way might be to buy a 58mm distribution tool off the peg and turn it down on a lathe but as you’ve got this far that tamper looks ideal.
I use one of the Espro calibrated tampers and love it. It gives a little click when you've applied the right pressure which is strangely satisfying. There's so many variables in making good espresso it's nice to be able to eliminate one.
And a section view, for those interested.
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