Wood-mounted movement issues

Discussion in 'Clock Repair' started by bikerclockguy, Oct 11, 2017.

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  1. bikerclockguy

    bikerclockguy Registered User

    Jul 22, 2017
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    I'm having problems with a Sessions movement that mounts with wood screws. The movement runs great on a test stand, with everything snugged down properly as it should be, but once I install it, I cant get it right. The front plate has 4 screw mounting tabs bradded onto it, and it mounts to the case with 4 short wood screws with a thread length of about 3/8". The problem seems obvious, but I haven't had any luck solving it. What appears to be happening is that when the screw are tightened, it distorts the plate and puts the movement in a bind, and it won't run. All of the screws are straight in the holes, nothing stretched or going in at an angle, and I've pretty well used up my automotive and construction bags of tricks. I've tried all of the combinations of tightening sequences, cross-corner, top first, bottom first, left and right first, and none of it made any difference. When the movement is mounted tightly in the case, things are in a bind, and the tighter the screws, the worse the bind. I don't have much experience with clocks, and I know they don;t have to be cranked down with a breakover bar and a cheater pipe, but given the short length of the screws, I would think they would need to be at least a degree past snug, to be properly braced for tension during winding ans so on. The one thing I haven't tried is loosening all of the nuts on the back plate, tightening, the mounting screws and then tightening the nuts back down, but I don't have much faith in that doing the trick. I can get it to run for brief intervals and at varying degrees in and out of beat by loosening different combinations of mounting screws and plate nuts, but it just doesn't want to run with everything snugged down. Does anyone have a good trick up their sleeves for this? i searched the forum, but didn't find anything on tis particular issue. Thanks!!
     
  2. Willie X

    Willie X Registered User

    Feb 9, 2008
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    Put the movement in the case, with the dial face down, in place but no screws. Now see if the movement will rock on its mounting feet. If yes, you can bend one of the foot tabs, or place a thin shim or flatwasher under the high foot.
    Willie X
     
  3. bikerclockguy

    bikerclockguy Registered User

    Jul 22, 2017
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    Thanks, Willie! I guess I was stuck on thinking it ran before like that so it should run now. After reading your, reply, it occurred to me that the movement has been out of the case for several weeks, and we've had varying degrees of temperature and moisture; the perfect recipe for wood to shrink, swell or do the things old wood does. Two heads are definitely better than one, and I'm betting that's the problem. I'm gonna do that right now, and I'll let you know how it works out!
     
  4. bikerclockguy

    bikerclockguy Registered User

    Jul 22, 2017
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    Well Willie, I'm closer in one respect and farther off in another. I shimmed up one bracket and straightened out another one that was a little off, and git it to run for longer intervals, in beat, but still couldn't get it quite right. Then as I was loosening one of the top screws, the face board moved forward about a quarter inch, and I noticed an angled gap at that corner. I looked closer, and I think at some point, someone threw this clock down and smashed it in a fir of rage, and then it was poorly cobbled back together. There are wood screws and a few nails that I'm pretty sure aren't original to the clock, gaps where there shouldn't be gaps, and right angles that aren't quite right. So, now I'm going to have to do some wood work and get the case lined out before I even have a good reference point. I've been sorely tempted to throw this thing in the dumpster more than once, but now it's a quest, lol. I think I'm gonna take a break from it and finish another clock, but I'll keep you posted on the progress.
     
  5. Willie X

    Willie X Registered User

    Feb 9, 2008
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    Natural warping is rarely the problem. It's usually something like you discovered.

    The last time I ran across this type problem was on a cuckoo clock. The movement was mounted on little 1" square plywood blocks. Little did I know that, on one block, the top ply of one of the blocks had come off.

    Also, when the mounting feet are bent, it often takes quite a bit of measuring and the use of a good straigtedge to figure out exactly how to straighten things back out.

    Willie X
     
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