The Old Lawnmower Club
Collection, Preservation and Display of Old Lawn Mowers
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Drum to bedknife adjustment

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N467US Mon, 06/05/2024

Hello,

I'm trying to adjust my cylinder drum on a Suffolk punch 43a. How tight up against the bedknife should it be? I seem to find that when it's tight enough to cut two pieces of paper across the full length that the clutch struggles to rotate the drum. Is there any rules of thumb for setting this?

Many thanks in advance :)

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wristpin Mon, 06/05/2024

If the cutting cylinder and bed knife have been properly ground and set, I would expect them to cleanly cut a single thickness of dry 80/90gm copy paper , with virtually no interference between cylinder and bed knife. At the worst , with a folded strip, cut the top layer and bruise the second.

In the case of a Suffolk with the “Unit” bottom blade - combined bed knife and sole plate, one is, to some extent at the mercy of the rigidity - or lack of rigidity of the machine but with a bit of care , they can usually be set up to cut cleanly without undue pressure .