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| Cam Clamps Slipping http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=44942 |
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| Author: | Richard Loren [ Mon Jan 19, 2015 10:25 am ] |
| Post subject: | Cam Clamps Slipping |
Hello, Several of my cam clamps slip back and do not hold well. I roughed up the surface with sand paper but it did not make much difference. I hit it with a rat tail file to make it rougher and it still slipped. I slid a piece of sandpaper in and it seemed to work better. Any ideas on how I can get these clamps to work well? Thanks... |
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| Author: | Joe Beaver [ Mon Jan 19, 2015 11:31 am ] |
| Post subject: | Re: Cam Clamps Slipping |
Some cam clamps have a smooth metal bar, some have little grooves every 1/16" or so. For me the ones with the grooves work better. I assume yours do not have the grooves if you put some in with a file it has to help. But, I have never tried it. |
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| Author: | Alex Kleon [ Mon Jan 19, 2015 11:56 am ] |
| Post subject: | Re: Cam Clamps Slipping |
Don't over tighten the clamps, that can cause it to slip. Use just enough pressure to mate the joint. Alex |
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| Author: | cphanna [ Mon Jan 19, 2015 12:16 pm ] |
| Post subject: | Re: Cam Clamps Slipping |
Hi, Richard. Do mean the clamping head is slipping on the bar, as Joe surmised? I've got one or two home made cam clamps that do the same thing. If so, I think the fit of the pins that ride up and down the bar needs to be more snug. The slot itself can have a loose fit, but the pins need to bear against the edge of the bar without the head pivoting up. The problem with roughing up the edges of the bar is that you're loosening the fit at the same time. Do you have pins or rivets that bear against the bar when the cam is thrown? If so, they are probably worn or bent, or perhaps not positioned close enough to the bar. You can consider driving those out, plugging the holes and then re-drilling and inserting new pins for a better fit. Or, if you have room, drilling for a supplemental set of pins that ride closer to the bar. Pictures work better for me. In this schematic, the black dots represent pins as they SHOULD be positioned relative to the bar. On my two slipping clamps, the pins have become bent and loose. Check for this on your clamps. |
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| Author: | Richard Loren [ Mon Jan 19, 2015 1:42 pm ] |
| Post subject: | Re: Cam Clamps Slipping |
Whoops...let me clarify...When I pull the cam over...it is not as snug as it used to be. The cam moves backward some..after I pull it over.. the wood on wood area is slippery, no bite.. It is not slipping at the bar |
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| Author: | cphanna [ Mon Jan 19, 2015 2:50 pm ] |
| Post subject: | Re: Cam Clamps Slipping |
Richard, if your jaws are slipping on the surface to be clamped, try gluing some cork pads on them. You can buy rolled cork gasket material at most hardware stores or in hobby shops. If the cam itself is slipping, it's probably worn. You could easily make a new cam. |
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| Author: | Richard Loren [ Mon Jan 19, 2015 2:52 pm ] |
| Post subject: | Re: Cam Clamps Slipping |
Thank you... |
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| Author: | Pat Foster [ Mon Jan 19, 2015 3:58 pm ] |
| Post subject: | Re: Cam Clamps Slipping |
Richard Loren wrote: Whoops...let me clarify...When I pull the cam over...it is not as snug as it used to be. The cam moves backward some..after I pull it over.. the wood on wood area is slippery, no bite.. It is not slipping at the bar I'd try some fiddle bow resin. Pat |
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| Author: | Kamusur [ Mon Jan 19, 2015 4:16 pm ] |
| Post subject: | Re: Cam Clamps Slipping |
Some excellent tips, definitely a borrower ty. Steve |
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| Author: | Richard Loren [ Mon Jan 19, 2015 6:57 pm ] |
| Post subject: | Re: Cam Clamps Slipping |
Pat... You got me thinking !! Create friction..How? Wet the wood. I took a Q tip and wet both surfaces with water. Water probably swelled both wood surfaces somewhat also..Bingo..it's tight now. Works for now..we'll see in the long run...thanks guys... |
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