Put it in the freezer. Maybe run some hot water over the jig and try not to make the tip wet.
Maybe the metal will expand quicker than the leather tip will.
I saw these before. Looks interesting other than the fact that when screwing the jig down over the tip, you will be exerting a circular force, (sideways skewing), to the tip rather than when using the Piccone Press and putting pressure straight down on it.
I tried using a couple of fender washers with a bolt in the hole to tighten down.
I found that instead of applying a straight downward force to the tip, that it was skewing it sideways.