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Fixing stripped screwholes

Discussion in 'Accessories / Connections' started by Guitarfreak, Jun 27, 2009.

  1. Guitarfreak

    Guitarfreak Well-Known Member

    A guitar that I am working on won't stay together XO. The screws that hold the faceplate/bridge down aren't doing their job because they have apparently been removed several times and the threads are completely worn down. I looked into wood filler and actually purchased some, but I'm thinking buying longer screws might be an easier fix. Has anyone dealt with this before? If you haven't specifically, but have experience with wood/screws, what would you do?

    Also, I'd like to stay away from fixes like jamming a toothpick in there, I'm looking for an actual fix. It's for a friend so I'd rather not hand him his guitar back in Frankenstein shape :\
  2. Space

    Space Well-Known Member

    "I'd like to stay away from fixes like jamming a toothpick in there"

    It's not so much a toothpick as it should be a piece of wood shaped to fit the hole and glued into place. Longer screws might work, but the stripped part of the hole should be filled with wood or the incredible tension placed on the bridge by the strings will pull on the screws and in short order, have them coming loose again.

    Of course if you can get a screw that is as wide as the existing hole, this might work as well. But be prepared, there may actually be a change in the way the instrument sounds if the bridge alignment or body mass is altered, depending on the quality of the instrument.
  3. jg49

    jg49 Well-Known Member

    I completely agree with Space the proper fix is to glue (with an appropriate wood glue) new wooden inserts, typically the correct diameter hardwood dowel available at most good lumber yards. Bring the screws with you to gauge the diameter which should just marginally exceed the screw dia. These should be glued and pushed into the holes by hand, snug enough to require some resistance but not so much as to require being tapped or driven into place (which could easily split the guitars wood weakening the repair.) Most wood screws are tapered, examine yours closely, so some light sanding of the tip of the dowel may be in order. I usually leave a couple of inches sticking out until after the proper drying time (usually at least 24 hrs) then carefully trim the excess dowel with an exacto knife. You must then carefully pilot the holes with the correct size drill bit to about 3/4 of the depth that the screw will seat at, take into consideration whatever the the thickness of the faceplate/bridge is. While the screwholes may have been stripped from use many wood screws are over torqued by inexperienced people. They should be turned until just snug. A small drop of clear nail polish applied just under the head prior to install can help keep screws from rattling loose but still allow later removal.
  4. TheJackAttack

    TheJackAttack Distinguished Member

    What we do in the piano tech business is shave a maple hammer shank (three or four pieces) and use hide glue. This technique is used all the time for lid hinges, lyres, cheek blocks, et alia. Toothpicks will not work as they are a soft wood usually. I've done this on many a battered piano whether a Wurli or a Steinway.

    In instances where great strength is needed like in the pinblock or leg mountings or a restoration job, a whole is drilled larger than the original and plugged with a hard wood plug-preferably inserted in cross grain (again with hyde glue). This plug is then drilled with the proper size whole.

    That's a lot of work for a guitar IMHO. If you have the depth available, longer screws (or originals) and hard wood shavings would be the way to go.
  5. Guitarfreak

    Guitarfreak Well-Known Member

    Perhaps a combination fix, like longer screws AND wood filler on the top portion. The faceplate screws are only superficial, it's the bridge screws I'm worried about.
  6. TheJackAttack

    TheJackAttack Distinguished Member

    Wood filler is not a proper fix for a screw hole.
  7. Guitarfreak

    Guitarfreak Well-Known Member

    I know, I just called my grandfather and he said the same thing. ":\ I'm definitely going to get 1/2" wood pointed screws, I think the dowel idea is the best one yet, but a little overkill considering I have to do it to 6 bridge holes all very small. Maybe I'll see if a toothpick will fit in there as well.
  8. TheJackAttack

    TheJackAttack Distinguished Member

    Get out the yellow pages and look up piano tuners. Call one up and ask to purchase a couple of hammer shanks. If he/she asks tell him you are repairing some screw holes-he'll understand immediately. If you can wait a couple of days, I probably have some in my traveling kit with me here in Yellowstone and could mail you a couple.

    Another source would be a hard wood shim found at almost every hardware store. Simply split it into small pieces and break off at the proper depth. Elmers or other yellow glue will work for this purpose too even if hide glue is better.

    Ask your grandfather, he'll walk you through it.
  9. TheJackAttack

    TheJackAttack Distinguished Member

    Addendum: you only need some decent sized slivers to do the job right. You aren't plugging anything with this route.
  10. jg49

    jg49 Well-Known Member

    Just remember something that the average electric guitar strung with high E 0.10" has well over 130 lbs of tension on it, imagine a sack of concrete hanging from the bridge plate, and even more when doing double note bends, using a whammy bar, etc. While this load is transfered obliquely it is these six tiny screws that counteract that weight. You can use any hardwood shim or dowel to be sure, I suppose you could drill out larger holes and plug them especially if the area you are talking about is hidden by the metal bridge plate. I know you said this is a Lotus (I've never heard of that maker) but sure as hell would not want you doing that to my vintage Les Paul!
  11. MadTiger3000

    MadTiger3000 Active Member

    Wood filler is more cosmetic, and for basic structure. Never for strength.
  12. BobRogers

    BobRogers Well-Known Member

    Cleaning the holes out by drilling a larger hole and then filling with new wood is the standard way to do this. I'd drill a hole at least twice the diameter of the screw - so you will be tapping into wood rather than a combination of wood and glue. Our local hardware store has hardwood dowels in 1/8, 3/16, 1/4" and up. Use a small sanding block to make sure the ends of the dowels don't stick up above the surface.

    You can check with the various luthier message boards, but my guess is that this is exactly what would be done to a vintage Les Paul. If the guitar had a lot of historic value they might try use one of the various super glue versions to harden the threads that are still there. But if the old wood has been stripped out there is no cure but to put new wood back in. The key is doing a clean neat job (even if it is going to be hidden under the bridge).

    By the way, using a toothpick is actually another way of doing this same thing. If the hole is small and the toothpick is hard it is a perfectly good repair. Its not quite as good a drilling out and putting in a dowel larger than the screw since the screw will be biting into a combination of the wood of the toothpick and the guitar and the glue. But it is often an effective repair, it's easy, and it doesn't have any chance of doing damage.
  13. audiokid

    audiokid Staff

    I like Bob's pro way of repairing however, I found this video and thought it was interesting.

  14. TheJackAttack

    TheJackAttack Distinguished Member

    Precisely the method piano tuners use all over. The exception being I use two or three hard wood shavings instead of filling the hole entirely. All that is really needed is something for the screw to grip onto.
  15. Guitarfreak

    Guitarfreak Well-Known Member

    Bad cameraman, great technique.
  16. jg49

    jg49 Well-Known Member

    Fixing stripped screwholes on a guitar

    This topic interested me and I called Barry L. Master Luthier, author, and guitar repairman for over thirty years. I recieved the following advice. For pickguards, coverplates, tuning machines, etc. the hardwood shaving method is the preferred system. For neck and bridge screws this is not acceptable, too much stress is transferred to the screws. Bob Roger's system is recommended, drilling out a larger hole and using a hard wood dowel.The dowel should have two 1/32" grooves cut the full length of the dowel with a file or thin handsaw to allow excess glue to escape the hole when gluing. Excess glue can cause the dowel to back out during the drying process or cause cracks in the body or finish. Yellow aliphatic resin glue (Titebond or Elmers Special Carpenters Glue) preferred. Use a drill press to drill holes and does not recommend hand drilling for the dowels or pilot holes.
  17. Genereaux

    Genereaux Active Member

    Hi. I never did a 'formal' introduction on this forum.
    My name is Sean, I've played guitar for 25 years. I've been a stagehand (MANY forms thereof) for around 18, much of that as a guitar tech. And have done quite a bit of repair/maintenance.

    Big deal, I know. But I just wanted to shine up my two cents before I gave it;

    It would be helpful to know what kind of guitar (well, bridge specifically) we're dealing with. If we're talking a two screw Floyd or Gibson bridge, I would recommend tossing out the original wood screw anchors and upgrading to ones with a threaded bushing (like these http://www.stewmac.com/shop/Bridges,_tailpieces/Electric_guitar,_non-trem_bridge_parts/TonePros_Locking_Studs.html)

    BUT, I doubt this is the case, otherwise that may have already come up.
    So, chances are, it's likely a strat style trem or non-trem fixed bridge.
    OK, then.
    Yes, longer screws ARE a good approach if you have another 1/4 inch (at least) of fresh wood to bite into. But it would STILL be a good idea to throw a toothpick or two (you GOTTA show some love for the toothpick. It's not just a jerry-rigged fix anymore)in there with some glue.
    Larger DIAMETER screws would be nice too, if the screw holes in the bridge plate could accommodate it, but that rarely happens.

    Personally, it has to be a pretty drastic circumstance or reaming for me to consider a full plug/re-tap. ESPECIALLY if there's any 'collectible' value to be considered.
    Honestly, for a fixed bridge with more than three screws, my inclination is to use two toothpicks per hole (which typically equals 2/3 of the screw diameter) provided theres still SOME grab with the screw/existing hole.(If not, then three toothpicks) Then glue, screw and set overnight.
    Remember, the string tension on the bridge screws is a SIDE force, rather than a direct force. So, for a 4 or 6 screw mount, I'm comfortable with toothpicks.

    A KEY benefit to the toothpick/shavings method is, there is VERY LITTLE to screw (sorry; pun) up. Whether it's a mid-fifties White Falcon, or a $150 pawn shop deluxe, if you "oops" a drilling, it's BAD. Best case scenario for recovery then is to drill wider. Worst case is to use that wood filler on the backside of the guitar.

  18. Guitarfreak

    Guitarfreak Well-Known Member

    Hey Sean, welcome to the forums at RO. Thanks for the tip. After all the good advice I've gotten around here I was looking forward to putting some of it to good use, but I was kind of embarassed to find that new screws were all that was needed lol.

    I bought some stainless steel #6 3/4" screws for the bridge and they took perfectly. I am thinking that they are a bit long for the faceplate though so I'll probably go with #6 1/2" for those.
  19. Genereaux

    Genereaux Active Member

    I don't hear the term 'Face Plate' much, but I assume you're referring to the pickguard?
    If thats the case- there's no cause for concern at all to use the glue/toothpick route.
    BUT, if you were lucky enough to find big enough for a fresh bite and small enough to fit the pre-existing pickguard(faceplate) holes, by all means go for it.
    Certainly quicker and less 'messy'

  20. dave_p

    dave_p Active Member

    round toothpicks and elmers wood glue is a perfectly acceptable fix for this problem. i have done it several times and the repairs have lasted over a decade with no need to re repair. most luthiers will tell you the same, and if you brought the guitar in to a place, chances are, thats exactly what they would do. no need to overcomplicate/over-engineer a common problem. once you bring dowels and power tools into this you run more risk of f-ing something up.

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