Uneven pressure on C&P Pilot

I am having uneven pressure issues on my pilot. I can get a crisp deep punch on anything smaller than 1” but when I try to use a single large 4” wood letter M, I get nothing or only 1/4” of the letter.

I have checked the height of the form and know that is not the issue. I have also adjusted whatever I am printing around on the chase (looking for a sweet spot) and I still get the same results.

It also occurs using my bcbase and polymer plates. Only 1/4 or 1/2 is a crisp punch but the rest is not even a kiss.

The very nice previous owner of the press told me he adjusted the bolts but I was not sure that is the way to resolve.

Any ideas?

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Sounds like you’ll have to adjust the impression screws at the back of the platen. The Letpress archives have a number of detailed descriptions on how-to, I believe.

But, you’re just not going to get as much punch with a 4” letter as a 1” It takes 16 times as much pressure with the larger figure (assuming a square shape) than the smaller. I’ve heard the figure of 84 lbs per sq. inch as necessary for good (kiss impression, likely) printing, probably more if you really want to punch it into the paper.

A bit of trivia…a cylinder relief press like a Miehle or KSBA can exert between 200 and 500 PSI. For those working in intaglio, a manually driven etching press can exert upwards of 6000 PSI.

Thanks for the information and input. I think I have been to work out the pressure issues.

This article helped too: