Base Clamp unlocks periodically (APDC+)

Discussion in 'Stringing Techniques / Stringing Machines' started by POM, Jun 5, 2018.

  1. POM

    POM New User

    Jun 3, 2018

    Alpha Pioneer DC Plus (APDC+) bought new 2 years ago with ~ 400 string jobs.


    Base clamp unlocks periodically and has a tiny amount of play in the lever when closed.


    -- What’s making my base clamp unlock?
    -- What should I do to make it work properly?
    -- What's the correct periodic maintenance for this base clamp?


    For the last 3 months one of the base clamps opens/unlocks (infrequently) after the linear gripper releases the string from tension usually within fraction of a second to a couple of seconds. Sometimes it unlocks at random which really freaks me out with the "pop" noise! The base clamp unlocks maybe 1 in 20 times but still that’s unacceptable. When it comes undone on the mains, grrrrr, gotta start over but I’m not too miffed when it happens on a cross because it’s backed up.

    There are 9 pics each having a number in the upper left corner so please use those numbers when replying. In picture 3 & 6 you can see the interior of the clamp has some dark patches of what I would guess was some kind of lube initially? Well there’s like no real lubrication now as that black stuff, what little is left, is kinda hard or at least not slick. The gray metal is dry.

    Also on both base clamps, when closed/locked, there seems to be a little bit of "play" in the lever. Hard to describe but the lever can move a little fraction of a turn and not open...I can move it slightly. I'd prefer it to feel CLOSED and solid and I do close them pretty tight.

    I’d like to take both base clamps apart and do a very thorough cleaning and lubing to make them the best they can be for their age. Veteran stringers please help with as much detail as possible!









  2. Irvin

    Irvin G.O.A.T.

    Mar 15, 2007
    Marietta, Ga
    Check the adjustment and call Alpha,
    Last edited: Jun 5, 2018
  3. estabanj

    estabanj New User

    May 22, 2017
    Bay Area California
    I have this problem on a old Axis Pro at work that my boss purchased second hand.

    My clamps were in bad condition and needed a lot of cleaning. I talked to Mark and he was very helpful, although I am still working through the issue.

    I have found completely loosening of the set screw #8 and tightening up (completely) the bolts underneath, that go through #6 and #7, then adjusting the set screw #8 for optimum locking works the best, although it has not fixed it completely.

    As Irwin says call Mark, he is very helpful, even for someone with an old second hand machine like me. Please let us know how you get on.

    Irvin likes this.

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