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Topic: Sierra Session aluminium 'pitting' problem |
mickd
From:
london,england
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Posted 15 May 2006 2:09 pm |
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On my Sierra Session U12, the end-stops tend (over the years, through wear and tear) to cause a slight pitting in the aluminium rail. This isn't normally a problem.
But on my LKR (which lowers the E's) what seems to be happening is that the block that holds the end-stop in place occasionally moves a fraction, so that the end-stop no longer goes into the 'pit' but hits the rail just to one side of it. The result is that it doesn't travel quite so far now - hence the E's don't get lowered so much. This effect also happens in reverse i.e. I get the change tuned and then suddenly (maybe after a few days) it goes 10 cents out of tune (sometimes sharp sometimes flat - but always both E's at the same time by about the same amount).
I have looked carefully at the underside and the end-stop block looks solid to me yet the pitting under it is not all in one place so it must be moving. I am guessing the change-lock is a major cause of this, even though when I operate it (with the guitar upside down) I can see no such movement. I did change the cross-shaft on this change (from aluminium to steel) a few years ago so I suppose another possibility is that there is some slight lateral movement on the shaft which would have the knock-on effect of changing the impact point of the end-stop. Again, I can't see much sign of untoward movement.
Anyway, I reckon there are two things I can do about it : either fix the problem so that the end-stop always hits in the same place OR find some way of smoothing out the pitting so that it doesnt matter where it hits.
I've drawn a blank so far with fixing it - I can't even see the movement.
As for smoothing it out, I thought I could try some kind of abrasive (sand-paper ?) treatment or maybe try to fill the pit with some kind of tough resin.
Any ideas ? Has anyone had a similar problem ?
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Curt Langston
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Posted 15 May 2006 2:25 pm
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Mickd,
Call Tom at Sierra. He is a master builder, and can tell you the best, and safest way to fix it. He is very helpful on the phone, and will spend some time with you to get you fixed up.
Some may advise that you use a Dremel tool to buff out any pits or burrs, but be careful to use a VERY fine grit/polish if you choose this route. It is better to spend more time buffing something out, than using a larger grit, and end up grinding too much away.
I would call Tom Baker first though. He is at: 503-759-3155
Tom Baker. Standup guy! |
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mickd
From:
london,england
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Posted 16 May 2006 11:42 am
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Curt
I have spoken to Tom in the past a few times and I second what you said. He's always helpful - but I don't want to take up his time if I can avoid it, plus it costs $$$$ to call Oregon from here  !
Mick |
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