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Thread: Neck Angle Adjustment - Mando Banjo

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    Default Neck Angle Adjustment - Mando Banjo

    I need to adjust the neck angle on my old Slingerland mandolin banjo. I've done some searching, but can't find anythign on how this is done. Apparently it is no big deal if it has a threaded rod, but this one has a wooden post. Does anyone know how I should approach this?

    Is the post a permanent part of the neck? It looks like I should remove the screw in the end, back off the threaded nut on the metal part, remove the neck, add another shim, put all back together, and drill a new hole for the screw that comes in the end. Is this right? The wood post is split at the end, so I may have to do a bit of surgery on it to add some fresh wood.

    Any help will be most appreciated!

    Phil
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    Registered User sunburst's Avatar
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    Default Re: Neck Angle Adjustment - Mando Banjo

    On some banjos the dowel (the part you call the 'post') is a continuous part of the neck and on some banjos it is a separate piece that is glued into a hole in the neck heel. Either way, it is part of the neck.
    There is no real adjustment for action height in that type of banjo, usually. Some people drill a new hole in the end of the dowel for the screw that secures it at the tailpiece end so that that end is held closer to the head, but without re-cutting the heel of the neck for a different fit against the rim that is of limited use in adjusting the action height.

    How high is the bridge, and have you tried different bridge heights to 'adjust' the action?

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    Mandolicious fishtownmike's Avatar
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    Default Re: Neck Angle Adjustment - Mando Banjo

    At the front of the dowel near the neck is the neck adjuster. Theres usually a screw that offers movement of the neck. You may have to place shims between the heel of the neck and upper rim to obtain the angle you desire. I have a few of these with a similar adjustment device just not a slingerland...Mike

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    Default Re: Neck Angle Adjustment - Mando Banjo

    Before you do anything, you need to ensure that the Dowel stick is still ridgid in the end of the neck.

    I adjusted the neck angle on mine by elongating the hole that receives the tailpiece ball-mount screw. Then I put a shim in between the hold down ring and the end of the neck. that metal horse shoe piece has a screw that is tightened to finalize the adjustment.

    Mine is a Vega, but these don't seem to have much collector value and I needed it to be playable.

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    Default Re: Neck Angle Adjustment - Mando Banjo

    Quote Originally Posted by fishtownmike View Post
    At the front of the dowel near the neck is the neck adjuster.
    Study that closely, that's not usually an adjustment but is simply a mechanism to tighten the neck against the rim. I suppose shims between the heel and the rim would work, but I think re-cutting the neck heel is better, but much more difficult.

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    Default Re: Neck Angle Adjustment - Mando Banjo

    I am restoring a couple of mandolin banjos and If I am understanding the above comments people seem to think the adjustment is at the base of the neck just inside the rim is a neck angle aduster. It isn't. That adjustment can compensate for the missing tension hook under the fretboard but will not adjust the neck angle at all.. For a while I thought it must be a neck adjustment mechanism too... but it isn't.

    As John and 8ch(pl) suggest, the only way to adjust the neck angle is to elongate or fill and redrill the the neck attatchment screw hole. As mentioned the tailpiece attchment hole will have to be filed to correspond to the lowered screw hole in the pot. In my mandolin banjo needing an adjustment the movement of the hole would only be an eigth of an inch or less. At presen my fretboard extension just touches the skin head I am sure effecting the tone. Or I could just buy a new dowel stick (if mine is detatchable). I am working on a Slingerland. The label reads "SLINGERLAND'S PROFESSIONAL TONE SUPERIOR BANJO MANDOLIN", "No. 202" (number in pencil). it seems to be a decent instrument with the pot being formed from a single birdseye maple board with no lamination.

    PS: My wife and I just installed our first goat skin banjo head. It went on with little difficulty And only a little swearing, though it did help to have three hands.
    Bart McNeil

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    Default Re: Neck Angle Adjustment - Mando Banjo

    Playing clawhammer banjo for 50 years I am a good amateur banjo mechanic. The best options have been mentioned above.
    The easiest is to change bridge height to get the right action. If you are playing almost always in first position this could well fix your problem.
    Wedging a shim in between the pot and neck right at the end of the fingerboard can get you a little bit extra back angle but not much.
    Then comes the "real" fix- re-angle the dowel stick and shave the heel- for that the banjo leaves my mechanic hands and goes to a real luthier.
    Be yourself, everyone else is taken.
    Favorite Mandolin of the week: 2013 Collings MF Gloss top.

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    Default Re: Neck Angle Adjustment - Mando Banjo

    Thanks everyone, this sounds a lot more complicated than I first thought.

    The first thing I tried was a new bridge to get the strings as low as possible. They are now too low, meaning the string line from nut to tail is practically straight. The break angle of the strings over the bridge is so slight that I can't tune it without the strings jumping out of the slots in the bridge, so I will have make a new one that is taller. Even at this, the action is high, and the fingerboard presses down hard on the skin head, which can't be good for sound.

    My main problem right now is that I have promised to play this thing at a church music gathering at the end of the month, so I need it playable. I may just have to live wtih the high action and the orignal bridge, maybe go with lighter gauge strings. Doable, but not much fun to play.

    what about other materials to shim between the heel and the pot? Cardboard, felt, maybe a tapered wooden shim? Any of that worth looking at, or is it critical to have a solid wood to wood contact?

    Phil

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    Default Re: Neck Angle Adjustment - Mando Banjo

    Phil:

    I just took another look at my Slingerland and found the dowel stick to be detachable (not part of the neck). It is a seperate stick attached to the neck with a dowel either a separate dowel inserted in both the stick and the neck or the or the dowel stick itself with one end turned as a dowel and inserted in the neck. If yours has only a slight bend it might be possible to remove the stick and re-insert it in the neck upside down. Or of course that might overcompensate. But in any case you can get a new dowel stick from Stewart McDonald for not too much money if i recall.

    By the way.. In mine the dowel stick is also birdseye maple like the pot but the neck of the mandolin is some other wood.
    Bart McNeil

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    Registered User sunburst's Avatar
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    Default Re: Neck Angle Adjustment - Mando Banjo

    Quote Originally Posted by Spyder View Post
    what about other materials to shim between the heel and the pot? Cardboard, felt, maybe a tapered wooden shim? Any of that worth looking at, or is it critical to have a solid wood to wood contact?
    Occasionally, there actually is a good use for a credit card.
    Something fairly hard would be best, wood veneer, "plastic", something like that.

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    Default Re: Neck Angle Adjustment - Mando Banjo

    FWIW from an amateur... Based on having shimmed a number of bolt-on Fender-style guitar necks, I find thin "hard paper" card stock, such as index cards, to be both easy and convenient, especially since you'll need to experiment a bit. These days, file folders seem to be more readily available, but still cheap and easy to work with. Such card stock is, after all, simply wood processed into a more convenient format.

    You may need to set a "ramp" of, say, 3 layers toward one end, stepping down to two and then one layer, ending with wood-to-wood contact at the other end. Experiment!

    Typical "shirt" cardboard is too thick to blend easily, resulting big steps & gaps. And I'd avoid anything soft, like felt, that will absorb vibrations.

    Hope this helps!
    - Ed

    "What our group lacks in musicianship is offset by our willingness to humiliate ourselves." - David Hochman

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    Default Re: Neck Angle Adjustment - Mando Banjo

    Thanks everyone for all the good advice. You've given me the inspiration to actually take the thing apart! What I found is the dowel (actually square in cross section) is permanently glued to the neck. That metallic contraption at the neck end is indeed just to hold the neck in place, and tighten it up. To remove it, I simply backed off the screw and pressed the pin out of the stick.

    Played around with it some, added one shim of hard wood .030" thick to the one that was already in place at the metal rim. Also noticed there was a bit of slop in the fit of the dowel in the hole through the pot, this let me shift the neck up slightly. The restult is a darn near perfect alignment, with the fingerboard no longer touching the head, nice low action and much improved playability!

    Now for the downside. on the tail end, the stick had to move up, toward the head. I found two holes in the end from previous work, putting the screw in the outermost hole made it all fit like a glove. Unfortunately, when I tuned it up to pitch, there was so much torque on the screw that the tip broke out of the lower edge of the stick. I have come to the conclusion that this was done in the past, if you look close at my photo you can see where it happened. The fix was the second hole, which was more sturdy but ruined the neck angle. So, I figure some corrective action will be in order. A new rod won't necessarily work because the stick needs to be thicker, so I plan to cut out the area with the two existing holes, add a thicker piece, and redrill.

    Then all I'll need to do is stack some shims like was suggested under the heel, and I should be all set!

    Phil

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    Default Re: Neck Angle Adjustment - Mando Banjo

    You may need to file an angle on the inside edge of the square hole that the dowel stick fits into to relieve pressure from bending it up to reach that second hole. Just try to make it a corresponding angle for the path of the dowel stick and leave the outside edge of the hole alone.

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    Default Re: Neck Angle Adjustment - Mando Banjo

    I am currently working on three banjo mandolins and all of them have bent dowel sticks, all bending like yours.

    If I understand your observations someone drilled a new hole in the dowel stick to raise it slightly in the pot, and apparently did not fill the old hole. He just drilled a new hole below the old. That of course created a very weak area in the stick which eventually collapsed leaving a really big sloppy hole. Your solution sounds like it will work. Or drill out the old holes and plug with dowel rod and then add a fairly long maple wedge to the dowel stick so that it will hardly be noticable once sanded and vanished.

    I think you have a good plan and if done carefully it will hardly be noticable. It should not take long depending on your skill with woodworking.... Good luck!!!

    Bart
    Bart McNeil

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    Default Re: Neck Angle Adjustment - Mando Banjo

    Figured wood is not always a good choice for a structural part, but I have seen straight grained wood bend and warp also when used for a dowel stick. You can change the neck angle by shaving off a wedge of the dowel stick and as previously mentioned make a wedge to put wood on the opposite surface of the dowel stick, thus making it straighter and aimed right to get your action. You will have to do some planning so you get it just right, but it has worked before. I almost did this on a Slingerland a while back but instead steamed out the dowel stick and re-set it. The wedge is a much easier way to go if you are not concerned with originality or collectability.

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    Default Re: Neck Angle Adjustment - Mando Banjo

    Michael:
    Could you give us a very brief tutorial on steam bending bent dowel sticks? my mandolin banjos are not expensive instruments but i would like to know how to do it so I won't have to mutilate my instruments in any way. I used to be interested in boat building so I am somewhat familiar with the process. I guess my concern is: When you steam bend... after removing the finish and steaming the dowel stick thoroughly... do you clamp the stick in exact straightness or is it best to over compensate a little in hope that it ends up straight? or can staming be pretty exact if you do a good job of clamping it straight before it cools and dries?

    Thanks,
    Bart
    Bart McNeil

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    Default Re: Neck Angle Adjustment - Mando Banjo

    I hope I have not mislead anyone, I don't bend the dowel sticks. If they are indeed bent, I would replace them OR shave a long wedge off the top (facing the head) of the dowel stick and glue a long wedge to the botton side (facing away from the head) efectively changing the angle of the stick without disrupting the glue joint in the neck. This process leaves the dowel stick the same size it was to begin with, just angled lower so it puts the neck back a bit and lowers the action. The process also entails fitting the heel to the pot, much like what happens when re-setting a neck on a mandolin or guitar. I hope this helps.

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    Default Re: Neck Angle Adjustment - Mando Banjo

    What do you suggest on a mandolin banjo heel? The issue I have with a very ornate instrument made by Stewart Company is that where there was a thin sheet of veneer installed (black into a maple neck) it is deteriorating and some has fallen out, weakening the area. I have tried glueing in and clamping the heel (with pieces of thin wood) then leaving it sit for 24 hours dry time. When I reinstall the neck and bring the strings up to tension, the repair gives way with even more damage.
    If it ain't got at least 3 strings on it, it ain't worth playing.

    Just sittin back, pickin and grinnin!

    Thank you AMY RAY for giving me an interest in mandolin and bouzouki, as well as Bill M, and countless others!

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