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bean_fidhleir

Making the neck tenon fit better

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If you were going to shim out the neck tenon to more snugly fit to the mortice, would you stay with hide glue or go with white (or some other kind)? This would be a compensating repair, not a breakage repair. I've checked several sources (e.g. Strobel), but it's apparently not a subject that ever comes up.

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Perhaps because there were gaps that needed filling, and hide glue doesn't do gaps very well?

Still, the point is a good one, and I'd think that the neck should be made to fit snugly so hide glue could be used. With talk of how white glue creeps, I don't think I'd want that holding my neck in place. Still, as far as it being reversible, most of the luthiers seem to cut necks out when they need to change something about the neck set (Jacob doesn't though), so I'm not sure reversibility is the key argument here.

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I would not go for white glue even when some gaps should be filled. If there are gaps than the pieces should be better made fitting. But a good maker makes the fittings proper fitting.

Another issue is that white glue is very difficult to remove for the case of repairs. In fact white glue is not what a violin maker should have on the shelf!

Frits

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"most of the luthiers seem to cut necks out when they need to change something about the neck set (Jacob doesn't though"

Wow Seth, you make the average elephant seem forgetful...

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Jacob, that just stuck out in my mind because I'd always assumed that everybody got neck blocks out the way you do, and was actually mildly shocked to learn that in fact most people just cut them out.

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to answer the question: If the fit on the sides is just loose, I have taken two maple shavings cut thin and glued them together and clamped in a vice. This is a very thin shim. White glue works fine over such a large area. One can than clamp this with the neck heel and some plastic wrap to protect the heel from getting stuck. Then a small sliver of spruce for the edge of the top. Keep the white glue off the ribs. It is invisible after varnishing.

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eeek! Sorry all, I was inadvertently confusing. The mortice is a shallow (very little taper) dovetail, but the tenon is even less tapered, and therefore fits loosely.

So I'm planning on bulking it out with wood, and then trimming down to fit snugly. My question was meant to be: what sort of glue should I use to glue the make-up strips of wood to the sides of the tenon prior to the final shaping? I'm definitely not trying to use any sort of glue as a space filler - that's what was wrong with it in the first place. Once I get it re-fitted, I'll definitely glue it in with hide glue. It's only the shim bits I'm worried about (and I just now read John's reply saying white would be okay).

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quote:


Originally posted by:
bean_fidhleir

If you were going to shim out the neck tenon to more snugly fit to the mortice, would you stay with hide glue or go with white (or some other kind)? This would be a compensating repair, not a breakage repair. I've checked several sources (e.g. Strobel), but it's apparently not a subject that ever comes up.


I think hide glue would be a fine choice... but the question I had reading your post was: If the mortice is too shallow, are you planing to add a piece to the back of the foot as well as the sides? or.. is it just that the neck isn't tapered enough?

Also, if it's just the angle, is the heal already narrow? What's your button width?

Anyway, if you're making a change to the heal/foot, I'd treat it the same as a normal neck re-set from that point on... which I'd plug the mortice for in many cases (and start a clean mortice) or at least add pices to the side (if there is room for adjustment on the floor). Also, if you are building out the sides of the heal, you may want to consider adding on any extention at the foot that's required (to gain the correct overstand) before adding on the side pieces... depending on how much needs to be added and where.

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quote:


Originally posted by:
Jeffrey Holmes

If the mortice is too shallow, are you planing to add a piece to the back of the foot as well as the sides? or.. is it just that the neck isn't tapered enough?

The tenon isn't tapered enough (or at all, as near as I can tell). When I said 'shallow' I really meant the angle of divergence as seen from the top, not the inset depth. That depth, according to Strobel anyway, is fine: it goes about 2mm past the inner edge of the purfling.

quote:


Also, if it's just the angle, is the heal already narrow? What's your button width?

Again I have to apologise for the confusion. The convergence angle of the heel top to bottom, seen from the neck end, looks reasonable to the eye, tapering from 30mm down to 19 at the button, across 30mm ribs. The button extends 14mm from the purfling channel, so visually it's relatively broad. Or isn't that what you're asking?

quote:


Anyway, if you're making a change to the heal/foot, I'd treat it the same as a normal neck re-set from that point on... which I'd plug the mortice for in many cases (and start a clean mortice) or at least add pices to the side (if there is room for adjustment on the floor). Also, if you are building out the sides of the heal, you may want to consider adding on any extention at the foot that's required (to gain the correct overstand) before adding on the side pieces... depending on how much needs to be added and where.

I honestly wouldn't know how to begin deciding whether anything more is needed than gluing some shavings to the sides of the heel. The overstand seems about 5mm, maybe 5.5, whereas Strobel shows 6. Is that a significant difference?

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I'm bringing this back up because I have the same question: why

wouldn't shavings (hide!) glued to the mortise do as well as

plugging it--and less work to boot. (Some people call it laziness,

I prefer to think of it as economy of effort).I've re-set the necks

of several steel-strung guitars this way, and I expect there is a

lot more more strain on a guitar neck joint than that of a

fiddle.Dave Gardner (formerly ignored as Midwestern Cheapjack)

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For very minor adjustments on the sides of the mortise, shavings can work. With a proper neck reset there is no way to do it better, faster, and more effectively than plugging the mortise.

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Thanks, Jacob-This is a puffy Staineroid fiddle on which I glued a

a bit of maple on the neckheel to get the overstand closer to

normal, ut of course it now leaves a bit of empty space on the

sides of the mortise. (I'm using shavings to fatten the

mortise).Dave Gardner

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Dave, on most neck resets I've done (way into the three figures), all the surfaces of the mortise had to be addressed. In addition, I think I say say that without exception the fingerboard also needed to have the scoop and radius corrected. Apart from that, one also sometimes gets funny slants to the neck surface. To just do a mortise from scratch makes it easier and quicker for me. Then there is the not-uncommon situation of a badly-finished neck root heel...

I will agree that if the back of the mortise needs no work at all, shavings on the side can make sense.

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