Form roller clutch on a No. 4

Form roller gears showing difference in clearance Brass plate that engages form roller clutch, showing wear Roller that moves plate that engages form roller clutch

Hello. I am a newbie restoring a No. 4. I have cleaned all of the moving parts and am putting everything back in place. When I turned on the motor for the first time and lowered the oscillating and form roller assemblies, I noticed a faint clacking sound that didn’t seem right. I turned off the motor and examined the form roller gears. I saw that, when the clutch is not engaged, there is more clearance between the roller gears and the clutch on the rear roller (closest to the feedboard) than there is on the forward roller. The first photo shows this; for the photo I rotated the gear to better show the difference.

I then examined the brass plate that engages the clutch. There is considerable wear where the plate meets the roller pins, somewhat more wear on the forward side. The second photo shows this. I think this explains the clearance difference, though it also could be influenced by accumulated wear on the roller that moves the brass plate (third photo) or by the brass plate being a bit skewed, though it seems aligned properly.

My question is, how much clearance should there be between the roller gear and the clutch when the clutch is disengaged, and how would I achieve this in my situation?



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Paul Moxon, Moderator
6 years ago

Shims that are serrated are original to the press. Remember to remove the extra shims after you replace the clutch pins and.braze the clutch plate. Failure to do so may allow the gear collars to grind into the plate.

6 years ago

I was dealing with this issue, found this thread, and went to shim the cam wedge. I discovered that the previous owner had already done this with several 2 point leads! I added another as the temporary solution, but just wanted to say thanks for this resource so I could feel like a mechanical wizard.

Fritz Klinke
16 years ago

Nice pictures. The blueprints indicate a clearance of .010 to .020 between the “clutch throwout lever” (the naval bronze casting)when the pins in the roller ends are not being pushed in by the throwout lever. The clutch pins are cyanide hardened steel, but they do wear over time. We have new clutch pins, but no new bronze castings. The pins should be round on the end, and if that is not the case, then maybe they should be replaced as well as Eric’s recommendation for repairing the throw out lever.

Paul Moxon, Moderator
16 years ago

Once again I’ve been beaten to the punch by Mr. Holub. Bravo Sir!

Barbara: your mechanical acumen and ambition means you are no longer a newbie. You have accurately diagnosed the problem with your press. You already know the answer: clearance is sufficient when the form roller gear and the clutch block no longer makes contact when the carriage is at the feed board and you no longer hear the clacking sound.

Eric Holub
16 years ago

That is considerable wear on the flipper (which is bronze). Have a welder braze or solder new material into the holes and level them off. There might also be a lot of wear on the pins too, but replacing them wouldn’t necessarily make enough difference.
A temporary fix is to find the cam-wedge that pushes the flipper, and shim it out enough to get sufficient clearance; might just take a brass or a two-point lead. (There should also be a spring that pushes the flipper away from the pins except when the cam is in contact, which would reduce wear.) But the wear will continue and at a certain point in over-shimming, you’ll see wear from the end of the gear as well as the pin.
This is one of the many reasons to pay attention to the label on the press:
“Always lift inking rollers when press is not in operation. If rollers are left turning on ink drum, the ink will dry faster and the rollers will be subject to needless wear.”

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