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Topic: Williams adjustment help needed |
Randy Brown
From:
Knoxville, Tennessee, USA
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Posted 31 Dec 2011 3:26 pm |
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I have a pre-400 keyless u-12. I bought the guitar used and am trying to tweak it to my tastes. I've owned several Carters and a couple of Sho-buds, and I'm pretty comfortable working on them, but I need some advice on the Williams.
1. What is the proper way to adjust pedal slack? It has a collar with a set screw around each shaft which seems to control how much slack there is before the shaft starts to move. (see picture below). I noticed that some of the set screws were tight and others were backed off leaving the pedals some slack. How should they be set?
 [/img]
2. I have a strange problem where my 5th string raised note of C# goes way sharp when engaging my 9th string B-D pull (i.e with both A pedal and D lever engaged). With the guitar turned over, I engage the A pedal and the C# notes are in tune. While holding in A, if I engage my D lever, I can visibly see the A shaft turning another couple of degrees, resulting in my 5th string going about a quarter tone sharp. (the 9th string is correctly tuned to D). Apparently the D lever is relieving some of the tension on the 9th string allowing the shaft to move more. My guess is that the shaft may be twisting a little bit when engaging the A pedal, and that the reduced pressure of the D lever allows it to untwist causing the additional pull. Any thoughts, suggestions?
Thanks,
-Randy |
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Dickie Whitley
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Michael Johnstone
From:
Sylmar,Ca. USA
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Posted 1 Jan 2012 7:40 pm
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| That common problem is related to something in physics called the modulus of elasticity - specifically tensile modulus. In short,change that flexing aluminum cross shaft to an identical one made of hard steel. That's the only real fix for that problem and it's easy. Oh you could add a center bearing to that cross shaft(tricky to fabricate,make work well and can get in the way of other linkages)or even add a secondary micro lower(compensator)to true the sharp string but that usually opens up another can of worms because it often doesn't work in all combinations especially on a complex copedant like a U-12.I went thru all that on my U-12 Sierra until they made me a steel cross shaft. It really helped. Just yank it out and have it copied. Any decent machinist can take that aluminum part and copy it into steel for a few bucks. I'd start by asking Bill Rudolph. It doesn't have to be tool grade steel but something really stiff. Those are great guitars by the way. |
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Randy Brown
From:
Knoxville, Tennessee, USA
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Posted 7 Jan 2012 5:33 pm
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I spoke with Bill Rudolph. He advised me to tighten the set screws on the collars. They should be snug. That answered my first question, and also it has helped the second problem as well. I'll go ahead and post the info here in case it helps anyone else.
1. These set screws must be tight - they are not supposed to control slack. The ends of the cross shafts are round with one flattened part which is where the set screw tightens to. There is no adjustable slack on these models.
2. Tightening the set screws actually seemed to greatly reduce the detuning problem I was seeing. My A pedal set screw was actually a teensy bit loose allowing just a little movement of the shaft even after the stop was engaged. I tightened it up real tight, and now it detunes very slightly but nowhere near as much as before. It is quite usable now.
Thanks for the suggestions! And yes these are great guitars - easy pedal action, tone and sustain for days, and great looks. This one is blonde lacquered body with black endplates - a very unique looking guitar. |
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