Best Motor for C & P

Late to the post, but may be useful re Speed Controller for single phase motor 110 or 240, possibly you use resistors, thyristors or more hi-tech even and more expensive yet. One possibility,(not rocket science or expensive, put me right on line if I got it wrong!) keep the original belt and original driving pulley, onto comparatively small countershaft, with “A” section pulley at opposite end being powered through “A” section V belt driven by infinitely variable coned pulley on original motor swinging on original motor bracket adjuster. This system is already well tried and tested on every thing from tiny Multilith, Gestelith etc litho machines up to Heidelberg Platens and similar. Way back here in U K they controlled motors with banks of resistors or variable pitch brushes on the commutators, kept one warm in the winter but crucified the electric. No such problems with with coned pulley drives and as it was purely mechanical, you didnt have to find hi-tech hi-spec electronic whizz kids (at the price of course?) One appreciates that in the 21st century electronic wizardry may have left mechanical rubbish standing at the post, but I used a thompson platen for some time, with built in electric speed control (with variable pitch brushes) at full tilt it pulled virtually no current, slowed right down to run flimsy stock it dragged the mains down so much that “her indoors” moaned that I was shrinking the picture on the television. So I did a little horse trading with my friendly L/P dealer for the coned pulley from a heidelberg, Problem solved.

Log in to reply   1 reply so far

The Heidelberg cone pulley is the best solution. But they are not readily available and can be quite expensive from other sources. Still, I’d say that it would be worth the search to find some good mechanical speed control. My 10x15 uses the old original 1914 motor, and works fine - although I did have to service it once… about 35 years ago, I had to replace the carbon brushes… It took about 15 minutes and can be done by a 20 year-old press-mechanic-to-be…

Before I got the fancy 10x15, I powered my 8x12 C&P very nicely with the little motor out of a clothes drier.

That’s all it needed.

But, at 1725 rpm at the motor, the press speed was locked in to 30 impressions per minute; there was no speed control.

To “get up to speed”, I’d either spin the flywheel as hard as I could, or use the treadle to get up near the speed of the motor, then hit the standard light switch to put power to the motor.

Once it was up to speed, I would simply lift the treadle with the top of my foot and the hook would fall off the crankshaft - to the back, safely out of the way. Then I would continue feeding - at 30 iph.

BUT that is too fast for most hobbyists, so I don’t recommend a 1725 rpm motor for anyone these days. The point is that this free 1/4 hp motor worked fine for many years.

And - perhaps even more important is the fact that my hook was mounted by C&P so that when I raised the treadle, it fell towards the *back* of the press.

But DON’T TRY THIS with a Hern treadle hook. They are made to mount from the front, and if you raise the treadle while the crankshaft is turning with this treadle, it will become pinched against the press frame and will break. No harm to the press, but the cast-iron treadle is too brittle to handle any undue stress. I know of two of these cast treadle hooks that failed this way.

So. If you want to try the “raise the treadle” technique, be sure that the treadle will fall to the back and rest safely out of the way. If it falls to the front, you are toast…