T nuts and machine bolts...

Discussion in 'Luthiery, Modifications & Customizations' started by foreright, Feb 25, 2013.

  1. foreright

    foreright SS.org Regular

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    Hi guys,

    Another quick question if I may - I've seen builds on this forum (and elsewhere) using T nuts and machine bolts to attach a bolt-on neck. I've achieved a similar thing in the past using machine bolts and brass threaded inserts, with varying results and this way seems far superior, given that the T nut is "captive" - ie. is being pulled into the neck wood by the bolt rather than an insert which is being pulled FROM the neck.

    I was wondering what sizes and materials people are using for these? Stainless bolts and T nuts seems to be the "best", however they are 10x as expensive as zinc plated ones... for bolts, again, stainless bolts are horrifically expensive as compared to aluminium.

    Is going for stainless nuts/bolts overkill?
    What size do people typically go for? I was thinking M6, but drawing it out, they do look quite large, which I guess is not necessarily a bad thing...

    These furniture bolts were what I was thinking of: Flathead Connector Bolts / Furniture Screws
     
  2. Necromagnon

    Necromagnon SS.org Regular

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    I really can't help you as I've not arrived at this point on the bolt-on neck I'm doing. But I'll go for the same solution as you explain, with the t-nut. I really think it's the best. For the size, I was balancing between M5 and M6, I think it's good compromise. As for material, I think for the nut, there's no need to have stainless (considering where it lays, if your nut starts to corrode, I think you have some humidity issues... :lol: ), but for the bolt... I think I'd go for steel, stainless or not, but not aluminum. I think i'ts more paranoïd than something else, but I'd really go for steel bolts. And also, I'm not sure you can find black anodized aluminum bolts?

    Anyway, I'll keep an eye on this thread, there might be many usefull informations going around here.
     
  3. foreright

    foreright SS.org Regular

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    You can get aluminium machine bolts in pretty much any colour you want - motorcyclists use them to "bling" up their bikes... check this site out for example: Pro-Bolt Socket Cap Bolts.
     
  4. Necromagnon

    Necromagnon SS.org Regular

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    Thanks for the info and the link! But I understand now when you said "it's expensive". :eek:
    Also, for my part, I prefer 90° head screws, used with a ferrule. I find it muche more nice looking.

    PS: they also have a shop in France? Awesome! Thanks once again for the link, dude! :cheers:
     
  5. penguin_316

    penguin_316 SS.org Regular

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    I used the stainless steel Tnuts on my guitar I'm making. Here in the US you can get the T-nuts-washers-screws for under $10, must be expensive cause you re in the UK.
     
  6. OfArtAndArsenal

    OfArtAndArsenal SS.org Regular

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    Darren @ decibel said (on his db1 build thread) he used 1/4"-20 t-nuts and bolts, but I don't know if that is the same with his others.
     
  7. Necromagnon

    Necromagnon SS.org Regular

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    So it's almost the same as M6. I think it's good compromise.
    Also, not all the dimensions are available, it mostly depends on diameter vs length... I think availability greatly influences choice...
     
  8. ugly_guitar_guy

    ugly_guitar_guy True Djentleman

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    I use different sized T-nuts for different builds. I've found that 1/4"-20 t-nuts are very large and maybe a bit unnecessary. They're cheap, so head to the hardware store and pick some up in different sizes to see which you like to use more.
     
  9. silent_k

    silent_k derpa derp! Contributor

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    I used 10-24 T-nuts on my 8-string build for this reason -- also because 10-24 bolts fit through the ferrules I wanted to use. I installed the t-nuts by making a 3/4" recess for each with a forstner bit followed by a through hole (can't remember exactly the size, but just large enough for the threaded flange to fit through -- the forstner bit leaves a convenient center mark for aligning the drill bit). Then I cut out some 3/4" plugs with a plug cutter and made little covers for each t-nut so that when I glued on the fingerboard, glue wouldn't seep into the flange and gum up the threads. I've also used stainless steel inserts, also 10-24, which are a little tricky to install straight, but with a proper wrench it can be done. I would not use either brass or aluminum for this -- both metals are soft, and you want a good, tight join between the neck and heel, and hardware that won't wear out quickly. Overtightening, while a mistake with any kind of screw or bolt configuration, could damage the bolt or, worse yet, the insert. So far I've had good luck with stainless steel.
     
  10. foreright

    foreright SS.org Regular

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    Thanks for that - I think IIRC "10-24" is M5 x .08 in metric. Point taken about the materials being soft - actually I found a couple of sources for stainless bolts that don't have prices that make your eyes water so that would probably be most sensible :)
     
  11. Necromagnon

    Necromagnon SS.org Regular

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    :yesway:

    Great idea, thanks for sharing!
     
  12. silent_k

    silent_k derpa derp! Contributor

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    D'oh! I forgot about the metric conversion, but that looks right from a little conversion chart I just found. Glad you found a good source -- it took me a long time to find a good one for the size of inserts I wanted to use, and once I did I still had to order a lot of them to make it worth while (and the shipping cost was equal to if not in excess of the cost of the inserts themselves -- and this was within the US!). I imagine the shipping costs and taxes would be prohibitive, but some US sources for fasteners to look into are McFeely's Square Drive Screws - Screws, Fasteners, Festool Power Tools and more, McMaster-Carr, and Industrial Supplies from Reid Supply.
     

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