DIY Neck Tensioning Jig (Vinson/Gilbert)

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by galibier_un, Aug 21, 2019.

  1. galibier_un

    galibier_un Supporting Member

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    I’m ready to build a tensioning jig, and I was tempted to revive this thread (https://www.thegearpage.net/board/index.php?threads/gilbert-neck-tension-simultator-jig.1288395/), but it probably makes sense to have a DIY, build-based thread, especially since people seem to get bent out of shape with this whole necro-thread thing.

    Walterw & Soapbarstrat have some good tips in the above thread, especially regarding the pull down strap.

    Yup, surrogate bodies for bolt-ons are a no-brainer.

    I also like the idea of a lower compliance contact points for the support rods as well. I had thought of making caps from some wood that's softer than the softest neck.

    While building one is straight-forward, I’m interested in any other innovative variants that folks may have come up with.

    My tip of the day:

    The whole bent rod to center the dial-indicators under the neck’s center line seems senseless to me. I’d glue blocks of wood on the side of the beam and install a straight shaft.

    Routing clearance for the dial seems to be a result of people sourcing large dial indicators (trying to keep the jig height to a minimum).

    I found one with a 1.5” diameter face, and they’re only $14.95. I just received two today, and the horizontal distance from the centerline of the shaft to the center of the lug is .75” (rough measurement), so my strategy for this horizontal offset should work nicely.

    These indicators are at https://littlemachineshop.com (part #3716). I was concerned that the pin might not be spring loaded (working only by gravity, like the indicator on the Stewmac nut slotting gauge), but I took a chance. It does have a spring, so it will work upside down.

    With an overall length of 3”, it seems to me that all you have to do is drill a hole in the beam for the pin to clear. You won’t have to get out your router make a rebate.

    That’s all I have. What d’ya got?

    Here are some useful links for those new to this:

    The Vinson plans:

    https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=2ahUKEwj2zv6WpJXkAhVBqp4KHc0aBmoQFjABegQIARAC&url=http://api.ning.com/files/HAVVJu2zjUSpk9hp*TDhq8f1lJp1ROG20YrU1d1Hf5dio4kSJSaYiEjlplY7Z-WWBkW1RMQzrlwFVfOW9vt7uLNwUX-p69br/How_To_Build_a_Neck_Jig__Matt_Vinson.pdf&usg=AOvVaw0NrfiFJj2DqBQlws4lF_J4

    These two videos are a useful supplement to the Vinson jig instructions:




    ... Thom
     
    Last edited: Aug 21, 2019
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  2. hangten

    hangten Silver Supporting Member

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  3. walterw

    walterw Gold Supporting Member

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    OK, so i recently bought myself a thing (used on ebay)...

    [​IMG]

    [​IMG]

    and i can attest that the new metal version is far and away better!

    besides being way more rigid (and thus precise), every part of it including the three crossbeams can be slid along the rail and swung out to any angle left or right, on-center or off-center, making setup much easier and faster.

    being able to tuck all the support rods and dial indicators under the short span of an acoustic neck and then spread them out under a bass neck is a huge upgrade.

    i've already added a wooden spacer to the headstock push-up mechanism to get the height i needed, and i'm going to ditch the rubber covers over the neck support rods for soft wood of some sort. i also upgraded the four little body support pads by mounting big ol' 4" square wood cauls covered in cork on them. that should let me skip the whole step of futzing around with laying wooden slats across the support pads and trying to get the guitar on there without everything falling off. the fact that i can move the supports to basically anywhere under the body should mean that i can always find at least three spots to hold up even weirdly-shaped guitars.

    since it turns out "40mm 80/20 aluminum T-slot extrusion" is a common thing and people use it to build all kinds of crazy stuff, i think i'll be able to whip up a dummy body for fender necks without too much trouble or expense.
     
    Last edited: Aug 22, 2019
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  4. galibier_un

    galibier_un Supporting Member

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    80/20 is great stuff. I pondered building one out of it as well.

    This being a cheapskate venture for my own guitar collection, I still want to make a good tool and I'm also in the rigidity camp. That lashing method for set neck guitars always seemed weak to me.

    The thought occurred to me that I have to scour an aluminum scrap yard here in the Denver suburbs (for my day job).

    Since I'm ok for now with a setup for bolt-ons, it occurred to me that I might find some sort of I-beam there. Scrap alu runs about $4.50/Lb. so it ain't breaking the bank.

    You had to mention the adjustability for bass necks, didn't you?

    I have a feeling I'm going down a rabbit hole but that's where all the fun is :D

    ... Thom
     
    Last edited: Aug 22, 2019
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  5. Steve_U1S

    Steve_U1S Supporting Member

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    Congratulations on a very nice purchase.
    I skipped directly to the aluminum version for all the reasons you mention.
    Do yourself a favor if you haven't already; see if you can arrange to work in an angle vice for quick flat to playing position adjustment and back again.
    I definitely want to adopt your nut area hold-down approach; the fabric strap is too wishy-washy for this important job. I've gotten by with it, but I guarantee matters will become all the more stable and controllable once I do that.
    I like your cork-lined additions to the support pads - I've been using the slats, and it goes along ok... but I could see going directly to your method as well.
    Sometimes the feet without any extra on top works fine too - solid body wise. For a semi/hollow I'd go cork-lined slats etc. to spread the load.
    The tricky part for me... my work space is also my living space. I've come to a method of having an anchorage for the angle vice I mount my jig into, which is quick-bolted (wing-nuts etc.) to an old B&D WorkMate collapsible bench. I actually use the moveable 'vice' top of it plus a second set of mounting holes in order to move from playing/jigging position to 'working'/flat position.
    Drop sheets and all that good stuff...
    It's what happens when a person like me takes a more-or-less hobby and goes deep and wide with it =]
    In truth I have worked as a store's part time in-house tech (maaaany years ago in fact), which I left behind because of other time commitments.
    But I continued - and continue - to delve deeper into the craft and acquire more specialty tools... and continue to look after instruments of some of the people I encountered over 3 decades ago.
    And of course, I eventually added fretwork to the fray.


    BY THE WAY; worth mentioning, and I actually submitted this in written and video form to StewMac, though I don't know if they've done anything about it:
    The rods on which the dial gauges are mounted have what I consider an unacceptable amount of slop in them; I showed StewMac a video I made of an instrument jigged up, and the fact that the positioned dial gauge would, with the slightest movements or pressure etc on the instrument, allow a sway of .004-.005" on both of them.
    Further to that I demonstrated that I had solved it; I drilled & tapped a second hole in each rod mounting block perpendicular to the original thumb-screws, and added a second thumb-screw to each one (I sourced those thumb-screws by going to an R/C hobby store - they have all kinds of interesting hardware and tools that I repurpose all the time). The second set is a bit smaller than the originals, but similarly these are made out of aluminum to minimize the likelihood of marring the shaft itself.
    It allows me to truly lock the sway out of those rods very effectively with rather minimal pressure - having them at right angles to the approach of the originals makes it efficient.

    ... I suppose that might class as a tip/trick as per the OP's suggestion of adding such things.
     
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  6. galibier_un

    galibier_un Supporting Member

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    Since I'm on the DIY track, but looking for rigidity (aluminum I-beam, etc.), I'm thinking that the ideal solution for both the neck support rods as well as the dial indicator rods would be threaded rod, with lock nuts. Of course, it will take a bit more time to bring things into adjustment, but I like the stability aspect. The thumbwheel affair always appeared to be an incomplete solution as well. I forgot to mention it above.

    Things are a bit bonkers around these parts, so I may not complete the project for a few weeks, and if/when I do, I'll snap photos.

    As far as flexibility for various scale lengths is concerned (since I'm not going to use the super cool 80/20 stock with all of their nice fittings), I'm thinking that I'll just tap multiple holes.

    This dialog is really helpful There are things that have been in the back of my head that I lost track of, as well as new, great ideas from the masters on this forum.

    ... Thom
     
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  7. walterw

    walterw Gold Supporting Member

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    maybe not the dial indicator rods (which shouldn't have any pressure on them), but for the neck up-pushing and the support rods i used to have a rig-up mounted into my bench with spool clamps slid through cheap hi-hat clutches built right into the bench, and one thing i liked about it was the way i could adjust the "up-push";

    the threaded rods of the spool clamps slid freely through the bench but had a wing-nut on them that bore down directly against the hi-hat clutches. i could slowly turn the wing nut to raise the rod up against the neck with zero backlash slop, then tighten it down with the hi-hat clutch when i got it where i wanted it.

    with a "proper" neck jig the support rods can simply be slid up into place by hand, you push them up until you see the dial indicators moving and then clamp them down where you think they're "touching" without "pushing"; that can be a little vague sometimes, especially if the padding on the rods is too soft. being able to slowly turn a wingnut to just get them nudged up there perfect is a cool idea.
     
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  8. Steve_U1S

    Steve_U1S Supporting Member

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    For the peghead lift function, wherever possible - having seen similar devices employed for a finer degree of control and minimizing moving bits - I use a (4 x 4"/100 x 100mm I believe) lab jack/platform device with a fine adjusting knob to scissor-lift the upper level with a minimal 'padding' to avoid any marking/impressions etc.
    Similar to what you've described, I'd really prefer to have a bunch of similar smaller lifts with shaped cauls on them to support the neck rather than the rubber/similar tipped rods.
    It works as is... but like you I believe it could be accomplished with even more finesse.

    Truth is, I believe there should be at LEAST 1 more dial gauge on there.
    After all, doesn't it require minimum 3 points to describe a straight or curved path?
    I've purchased another gauge (larger than I'd prefer...) and also another similar device with a small outreaching perpendicular arm with a mount - I intend to integrate at least one of those to compliment the two gauges provided.
    What I'd REALLY like is to be able to simply contact StewMac and request/purchase another mount/rod/gauge assembly to simply add on - that would be the path of least resistance for me to accomplish that. All I'd need then is to drill/tap/add the second thumb-screw to the rod fixture...
    Time to email StewMac.
     
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  9. wox

    wox Supporting Member

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    That first video, 25 minutes of metal machining, is very soothing in a weird ASMR kind of way.
     
  10. walterw

    walterw Gold Supporting Member

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    OK yeah, once you mentioned that i noticed it was a thing; i feel like i got the slop out by just working it and wiggling it and tightening it, but a second 90° offset thumbscrew would certainly make that problem go away quickly.

    anyway, a couple more pics of crude mods:

    [​IMG]

    by throwing that bolt across the eye hook there i eliminate any issue of my homemade metal pulldown wire being slightly longer on one side than the other and causing more pull on one side of the neck; the bolt will just tilt by a degree or two while keeping the pulldown force even. also it spreads out my wire pulldown loop, keeping it away from the sides of the neck (by "wire" i mean .026 plain guitar string) and being threaded nothing will slide around.

    the bottom of that brass turnbuckle may be some exotic backwards thread thing but the top part with the eye bolt is just regular 1/4 20, meaning the sky's the limit as to what could be fit in there. i'm imagining a regular short bolt fed through some kind of flat stock crossbar thing to hang my wire pulldown on, not sure what yet.


    [​IMG]

    here you can see where i pulled off the plastic sleeves over the neck support rods (the tops of which bulged a little, putting a nice air gap between plastic and metal right where i needed zero slop :mad:) and hastily glued on little bits of soft wood. much better, now i can rack up a guitar, knock on the neck with my knuckles and watch the dial needles not move :)

    also a good shot of the big pads i stuck onto the body supports, sturdy maybe 3/16" plywood with cork, attached to the body supports (after i peeled off the rubber caps) with that super-strong nitto double sided tape they use to attach acoustic pickguards.
     
    Last edited: Sep 16, 2019
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  11. galibier_un

    galibier_un Supporting Member

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    I picked up a 4 foot long "C" extrusion from a local aluminum recycling yard (3 sides of a rectangular extrusion). The walls are about 5/16" thick which simplifies mounting the support posts (I can tap directly into the bar).

    I started laying out the project which currently will only be for Fender scale bolt-ons (bass & guitar scales).

    It's obviously not suitable for a pro who would need moveable supports for multiple scale lengths but it will suit my needs.

    Project cost looks to be about $60, including the bar. I allocated a scrap, top loading Tele bridge I have on hand, along with a 4 string, bass bridge I found on eBay for $9.95 including shipping for the surrogate necks. Adding the value of these bridges to the project cost bumps it up a bit.

    Mocking it up, I think I have the concept down.

    Those small dial, dial indicators I posted above will really help in keeping the overall height under control.

    If all goes well, I'll have some photos within a week.

    ... Thom
     
    Last edited: Sep 16, 2019
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  12. Steve_U1S

    Steve_U1S Supporting Member

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    Walter - those are great mods!
    All duly noted - your wire hold-down is excellent. I look forward to seeing where you go with that in your next modification.

    And do yourself that favor and do the 90-degree offset lock screws for the dial gauge posts; it simplifies and sturdies up the lock-down of the positioning of the gauges.
    I was disappointed that I got no real feedback from StewMac when I sent videos and a couple of photos of the before & after results.
    I have half-expected to see new iterations of the neck jig show up with those screws added.

    That reminds me; I have neglected to email them to see if they can provide me with that third gauge and mounting hardware...
     
  13. galibier_un

    galibier_un Supporting Member

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    Forgot to mention ... I really like the turnbuckle idea for the nut tensioning "strap". I need to add another $0.85 to my hardware budget :D

    ... Thom
     
    Last edited: Sep 17, 2019
  14. walterw

    walterw Gold Supporting Member

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    looking at it again today, it strikes me that the neck support rods have these big ol' thumbscrews to lock them down while the dial indicator rods have tiny little thumbscrews.

    maybe the easier fix is to tap those holes out for the bigger thumbscrews? it's annoying that they didn't take more care to use the same parts for multiple applications here, like the bolts that lock down the components to the main rail are sometimes 5mm and sometimes 6mm, meaning you need two different allen wrenches to set the thing up :mad:

    thinking further, maybe the easiest fix (no metalworking) is to replace the little thumbwheels holding the dial indicator rods with actual set screw bolts that could be tightened with an allen wrench. it'll mean a third allen wrench but i think that will be my next step. even better if i can find thumbwheels with the hex hole in the center so i could position them by hand and then lock them down with the allen wrench...
     
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  15. KGWagner

    KGWagner Member

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    Glad to hear I'm not the only one whose living space is also his workspace <grin> This isn't the greatest pic, but you can see a few things I've done to mine...

    [​IMG]
    I found a flexible neck gooseneck lamp online and modified it to attach to the far side of the jig, for better illumination of the nut as it gets a lotta attention. Also, some self-tapping screws used for hanging rulers and whatnot come in handy sometimes. Dummy body is a lot stiffer than it looks - it's made of 9 layer maple die board. Stuff is wicked stable. Tuner ahead of headstock comes in handy sometimes for intonation adjustments. Not pictured - magnetic knife holders on the wall behind the jig to hold the dozens of files you need.
     
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  16. Steve_U1S

    Steve_U1S Supporting Member

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    Agreed re; differing bolt sizes for the whole thing.
    In fact one of the very first things I did for my jig is great a repositionable magnetic holder to keep all of the related hex keys for the jig right there on the side of the jig main rail.

    If the mounts for the dial support rods were a bit 'V'-shaped to give a firm set of contact points, directly opposite the push direction of the thumb screws, that would solve it too...
    For me, the hardest thing was finding a set of thumb screws that I liked - they needed to be of something softer than the rods, to avoid marring the surface or creating catch points to potentially fight against in the future... the ones provided are made of - actually I'm not sure; I only know that it's something softer than the rods. They might even be hard plastic... or maybe aluminum. The ones I added are anodized aluminum, and came from an R/C vehicle store.
    I make use of those stores often, as they keep various appropriate tools and specialty fasteners around as a matter of course, things not necessarily easy to come by at a 'normal' hardware store.

    For these reasons, I doubt I'd be in much of a hurry to use any type of tool to lock those down - I'd be concerned about marring the rod surfaces.
    The perpendicular thumb screws work perfectly. They could probably be nylon screws and still do their stabilizing job.
    Ultimately, I would suspect that even with a more firm tightening down of a screw to lock that rod into place, I think the innate 'slop' of the fit tolerance of the mounting block would still potentially allow for some sway of the rods - and moreso the further up they're extended, due to leverage and exaggerated displacement due to being further from the fulcrum of that movement.
     
  17. KGWagner

    KGWagner Member

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    I should also mention the stand is mounted to a 2'x2' chunk of 3/4" ply sitting on 4 large lockable wheels so I can move the whole thing around easily to get it out where there's more room to work around the thing, or just push it into a corner when I don't need/want as much real estate eaten up by the whole thing. This is a lot handier than you might think.
     
  18. Steve_U1S

    Steve_U1S Supporting Member

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    That's awesome. Perfect use of space and mounting options. Great set-up.
    Love the additions - reminds me of my work cart, which is a repurposed heavy duty outdoor BBQ convenience cart with shelves and - very importantly - a butcher-block wood top that's 1-1/4" thick. I added MDF layers on top of that not long ago so that I could create an overhang in order to mount a pattern-maker's vice as required (the basis of the StewMac repair vice, sourced locally, and will get a couple of their upgrade parts added when convenient).
    Anyway, the cart has mega upgraded locking casters (dual-wheel, spindle-lock, major league German casters), and has lots of hooks and catches lining the sides to hang my equivalent rulers and such. Overhead swing LED lamp with magnifier... power plugs fed through to both sides... PODX3 and a tiny Fender Tweed amp strapped in place for simple sound testing etc....
    Acquiring this and adapting it has literally changed my life... I can be found sitting at it even when not working on an instrument.
    (I even clear the top off and do Christmas wrapping on it =])
    But my space is so limited that I have to stow my neck jig and such when not in use - in fact, I created and attached a padded 'foot' to the butt end of it to allow me to stand it in a handy storage spot when not in use. The angle vice gets stowed separately, and the WorkMate it all mounts to folds up into a spot as well.
    Wish I could do the shop stand solution for that part - that would be the ultimate.
     
  19. Steve_U1S

    Steve_U1S Supporting Member

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    Oh my gosh... that's amazing!
    It's stable enough that you're not fighting against gravity then... that's remarkable.
    Inspiring in fact.
    I think StewMac suggested mounting it to a patio deck block or something...
    Locking casters... genius.

    EDIT: would love to see a photo of the base of that.
     
  20. walterw

    walterw Gold Supporting Member

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    good point, the dial indicator rods look like brass instead of the steel of the neck support rods and thus might get marred by overly tightened set screws. still, that wouldn't be a dealbreaker since those rods don't need to be positioned precisely, they just need to get the dial indicators up there within their adjustment range.
     
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