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.

bent bumper

thanks,
-alex
press eight seventeen
lexington kentucky


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8 thoughts on “Bent Bumper on Uni I”

  1. 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.)

  2. 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.

  3. 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!

  4. Eric- yup, I was lucky enough to borrow a uni I manual and copy it, so I’ve known about the wedge for L & S trip.

    Today I took the bumper off and straightened it, with a hide mallet and my work-table. Suprisingly, the hinges were bent too (where most of the problem was coming from), so I took them off and did my best to straighten then with a vice and machinist hammer (they were buggers). It looks pretty good now, and should work once I replace one of the metal clips that hold the extensions int he forward position.

    I don’t know how this happened to the press as the bumper was bent when I first saw he press, and it didn’t happen when I moved it. It was move once before though, from the journalism building at UK to the art building, so it could have happened then. During this move a stack of typecases were dumped over by the movers and instead of gathering up the type, it was chucked. Oh well…se la vie.

    A tip for anyone doing this in the future- I got the bumper back in using a putty knife between the spring and the body of the press, one side at a time. You have to compress the spring somehow to get it back in, and I found this to be and easy and quick method of re-assembly.

    -alex
    press817
    lex, ky

  5. 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

  6. the bumpers have extension attachments that swing forward (not pictured in diagram) that enable the bumper to operate on s.t. – but they don’t work correctly now because the bar is bent. So now I don’t use the bumper when printing on s.t… but if i fixed the whole thing i could use the bumper on s.t. and save my right elbow some work on large editions

  7. 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

  8. 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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