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Pots for Wood Topped Guitars, No Pickguard

Discussion in 'Luthier's Corner' started by Gilmourisgod, Jan 10, 2019.


  1. Gilmourisgod

    Gilmourisgod

    Jun 23, 2014
    Cape Cod MA
    A little flummoxed on this one. I'm building a Rickenbacker 4003/4004 clone of sorts, but all wood top, no pickguard. I've left the top wood thickness at 1/4" over the control cavity, the cavity depth is just under 1" clear. I ordered some 250K CTS pots for it, but the threaded portion of the shaft is only 1/4". All the other ones I've found online described as Long Shaft have a 3/4" threaded sections, too deep for my control cavity. I could use a forstner bit just bigger than the pot body diameter to sneak another 1/16" or so out of the wood top thickness, but it makes me nervous. Is there a "medium" threaded shaft version, something like 3/8"? If so, I can't find one online from the usual suspects. I'm using set-screw knobs, so it needs to be smooth-shaft, 1/4" diameter. Thanks for any leads or advice!
     
  2. Slidlow

    Slidlow

    Apr 15, 2009
    Oshawa, Canada
    Probably custom order.
     
  3. Jon Clegg

    Jon Clegg Supporting Member

    Feb 9, 2015
    Northern Virginia
    Last edited: Jan 10, 2019
  4. byacey

    byacey

    May 16, 2008
    Alberta, Canada
    Why don't you just route the control cavity deeper? When I built my cocobolo bass, I didn't use a pickguard either, as I thought it would be a shame to cover such beautiful wood in any manner. I left the top thickness 1/8" thick in the control cavity.
     
  5. masonsjax

    masonsjax Supporting Member

    Jun 10, 2010
    Frederick, MD
    Use the 3/4” pots and with an extra nut on the inside of the cavity you can adjust it to have whatever thread length on the outside you need.
     
    bumperbass, AudioTaper and Deep Cat like this.
  6. Gilmourisgod

    Gilmourisgod

    Jun 23, 2014
    Cape Cod MA
    I don’t have the cavity depth to use a pot with a 3/4” threaded portion. Ric bass bodies are only 1-1/4” thick. Leaving 1/4” for top thickness and 1/8” for the cavity cover = 7/8” for the pots. Leaving less than 3/16”-1/4@ for the top thickness seems risky, if the bass gets dropped on the knobs, they could punch through. Not too good on a wood top bass. Looks like my best option is the 3/8” thread CTS pots. Thanks for advice All.
     
  7. dwizum

    dwizum

    Dec 21, 2018
    The 6 string I just finished had the same problem of being thin-bodied, I only had 3/4" depth in the control cavity. the pots were "normal" 1/4" threaded and the top is only 1/8" thick (hard maple). It worked OK. I share your concern about the top being thin but in practice I'm not sure it's a huge issue. At least I hope not!
     
  8. Slidlow

    Slidlow

    Apr 15, 2009
    Oshawa, Canada
    One of the reasons why I don't bother with thin bodies.
     
    packhowitzer likes this.
  9. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    The top being thin wood over the control cavity is an issue. I've repaired quite a few basses with caved-in control cavities, where the knobs got smacked.

    My recommendation is to bore the holes through the surface wood to 3/4". Then make up a plate of 0.060" aluminum that roughly fits the whole floor (roof?) of the control cavity. Drill 3/8" holes in it for the pots and jack. Then epoxy that into the control cavity. That reinforces the whole control cavity. The pots & jack clamp on the aluminum, not the wood, and the nuts end up flush with the wood surface. Adjust the knobs right down close.

    As a bonus, the aluminum plate acts as part of the shielding.
     
  10. dwizum

    dwizum

    Dec 21, 2018
    Forget what I said, I like Bruce's idea. Having the pots sunk into the surface or at least down flush would be a nice visual touch, and the aluminum would be plenty strong. I wish I'd thought of that... :D
     
  11. Gilmourisgod

    Gilmourisgod

    Jun 23, 2014
    Cape Cod MA
    I like it. Now I gotta find some aluminum sheet stock....
     
    bound'n'blocked likes this.
  12. Gilmourisgod

    Gilmourisgod

    Jun 23, 2014
    Cape Cod MA
    It just occurred to me: that’s probably why my 83’ G&L L2k has a brass plate in the “bottom” of the cavity. There is no pickguard. I always assumed that was for shielding, but I wonder if it was mainly intended to reinforce the area around the pots? Would brass sheet work as well? I can get that at a local model shop.
     
    packhowitzer likes this.
  13. thisSNsucks

    thisSNsucks Supporting Member

    Dec 19, 2004
    Yonkers, NY
    The standard USA CTS pots have 3/8” long threaded portion.

    You don’t get as much thread length if you use the lock washer but they work with a 1/4” top.

    Other option is to route the material just behind the pots a little thinner. I wouldn’t do the whole control cavity as that would leave you with pretty thin wood.

    If you’re mounting a jack to the top, you’ll need a switchcraft with long threads.

    I’m doing all the same stuff on my current build and it works.

    Pots and jack were purchased from stewmac.
     
    Gilmourisgod likes this.
  14. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Sure, brass works fine too. Or stainless steel. Just a little bit heavier. I like 0.060" 6061 aluminum best; good stiffness, light weight, easy to work with, cheap. You can buy squares of it on Amazon, if all else fails. Handy for all kinds of things.

    https://www.amazon.com/RMP-063-6061...547214438&sr=8-5&keywords=aluminum+6061+sheet
     
    Gilmourisgod likes this.
  15. Jon Clegg

    Jon Clegg Supporting Member

    Feb 9, 2015
    Northern Virginia
    Yeah brass would work as well. Your model shop probably also has sheet aluminum from K&S if they carry sheet brass. Another place to check would be a TruValu hardware store -- my local one carries it as well.
     
  16. Jon Clegg

    Jon Clegg Supporting Member

    Feb 9, 2015
    Northern Virginia
    I think you just eliminated the pickguard from my Victory build.
     
  17. I had one guitar where the top was too thick for my pots. I thinned the area around each of the holes using a forstner bit from inside the cavity, then instead of using the washer that came with the pot I used a fender washer that fit inside the recess cut from the forstner bit. I figured this would help spread the stress on the thinner wood across a larger area. Kind of like the same principle used with snow shoes to spread a person's weight across a greater area of snow.
     
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  18. Hobby Lobby or any hobby shop.

    I had the same problem with a guitar I was building. It was the first time I had done anything like this. The pots were too short, and I tried dremel'ing the body thinner. No matter how much I thinned, I couldnt get the knobs on. As I was trying to get one of the knobs on the shaft, I pushed it through the top. I ended up having to just cut a hole in the body, and made a small pickguard type thingy with just the knobs. It looked ok, but not what I wanted.

    BnB
     
    Last edited: Jan 11, 2019
    Gilmourisgod likes this.

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