Bent Bumper on Uni I

It’s finally time to fix the bent bumper on my Uni I.

The bumper bar itself has been bent from use, which makes the bumpers useless when the press is on short-trip (when in s-t the bumpers stick out from the press instead of hugging the sides of the press). Has anyone ever straightened the bumper bar? I’m not worried about disassembly/assembly, as I’ve taken that part of the press apart before when I was working on the adj. bed. But I’m worried that if I simply straighten the metal then it will bend back fairly easily. What’s the right way to go about fixing my bumper bar?

Any advice is appreciated.

 

thanks,
-alex
press eight seventeen
lexington kentucky

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Eric Holub
Editor
17 years ago

If you don’t have the “Gripper trip cam”, you would find three empty holes on the far side of the press between the rails near the bed end (and your grippers won’t open at the end of the bed). The cam is a bar with one tapered end (taper goes toward the feedboard) and has two posts which fit into the holes. It can be positioned in the two holes nearer the feedboard for short-sheet gripper release; or in the two holes nearer the bed end for longer sheets.
If a manual Uni I press doesn’t have the extension blocks for short sheets, running a long sheet with short release might loosen the sheet before the tail is in position to be grabbed. When feeding stiff or thick sheets it can make a difference. (At least that is what I recall, when 219ns is used cylinder set for long and gripper set for short and long sheet is fed.)

Fritz Klinke
Admin
17 years ago

I think the part being referred to is X-16742, Gripper Trip Cam, shown on sheet 188 in the manual, and referred to simply as “Cam,” with the part number. The manual is the same for power or hand as Vandercook put out only one version. Reference to part numbers, where known, is a tremendous help in understanding questions, and maybe even answers.

Keith Cross
17 years ago

The gripper wedge? I’m not familiar with that on the UniI in the shop at Mass Art. Care to elaborate? We have a manual, but it doesn’t seem to correspond to our press..from NA Graphics, but I think whomever ordered it got the power version…it shows a frisket arm…but we don’t have that. Hand crank baby. Please tell me more about the gripper wedge. Thanks!

Eric Holub
Editor
17 years ago

I had to fix a bent bumper from a non-AB Universal I, and thought it’d need a hydraulic press, but my machinist just pounded it carefully with a leather mallet on a flat surface.
Under normal use the bumper springs should have prevented any damage. But the bumper I saw had been damaged in shipping, no doubt an unsecured cylinder crashed into the bumper, perhaps repeatedly, and not only bent it but broke off one of the posts. Maybe something similar happened to your press.
Not all Universals have those swinging short-trip extensions, a nice feature. You knew about the gripper wedge that has different positions for the short and long lengths?
Eric Holub, SF

The Arm
17 years ago

I now see you mention short trip (a feature only of the manually cranked presses) so clearly I was off track with my last reply. But I ask now- why are you running the carriage all the way to the end of the bed when it is on short trip? Isn’t this feature specifically to avoid your having to do so?

Daniel Morris
The Arm Letterpress
Brooklyn, NY

The Arm
17 years ago

Is this a power press? If so, it needs to be adjusted to stop earlier than it is so that it doesn’t hit the end and cause this to recur. I would suspect the clutch is set too tight too.

Daniel Morris
The Arm Letterpress
Brooklyn, NY

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