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sospiri

String break angle 158 degrees? Where does that come from???

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3 minutes ago, Davide Sora said:

Plus I make a slight taper of 0.5 mm from the upper corners to the upper block on the back

 

Just now, JacksonMaberry said:

So glad to know I'm not the only one who does the taper on the back!

Yep, but I also make a taper of 1.5 mm on the top, which I believe inscribes me in the team of tilted tops.:lol:

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4 minutes ago, David Burgess said:

Valid question. My making was sourced largely upon a restoration background, so with a little experience, it was a piece of cake to set a neck into an already completed body assembly. There might be easier and better ways.

Of course this makes perfect sense David. I should have clarified above -- my curiosity is more around why many schools teach this 'restoration informed' method in new construction, when there may be other workflows for jointing a neck that are easier for students to learn and execute. 

I just looked at an old trade secret article by Howard Needham that illustrates the method for jointing a neck before the back is attached. I have never done it this way but I think I will give it ago in the future as a learning exercise

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9 minutes ago, Davide Sora said:

 

Yep, but I also make a taper of 1.5 mm on the top, which I believe inscribes me in the team of tilted tops.:lol:

Ack, you're one of those "top tilters"!! 

I jest, of course. Many ways to skin a cat, er, violin...

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4 hours ago, ctanzio said:

It may not be the case that any part of the NECK ROOT is in tension under normal playing conditions.

 

I guess you are right in normal playing playing conditions.

Under abnormal playing conditions though, like when the neck joint fails, collapsing the fingerboard onto the top and shearing the neck away from the button, it switches to being in tension.

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Here is a visualization of the 90 degree mortise and why it is more likely to fail. Because the back and the front of the mortise are the same length there is no resistance to the shear force along the button.

As the neck hinges at the top of the mortise the joint opens providing no resistance to the shearing force of the failing joint. 

 

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The <90 degree mortise is stronger because the back of the mortise (and the neck heel) is longer than the front of the mortise. The shape of the joint provides resistance to the shearing force along the button. The neck must slide upwards as well as outwards to fail (this can be seen in the video by observing the change in position of the small red dot at the top of the ‘mortise’).

 

 

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Maybe it doesn’t really matter. And it’s a strong possibility I’m wrong about the whole thing. 

Necks aren’t the only things that fail.

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Your demonstration works for the situation where the neck is being bent sharply downward, all the glue joints have failed, the vertical dovetails on either side fail to grip the neck, the button manages to stay intact from the blow, and the neck pivots right at the outer edge of the button. I concede the point for such a catastrophic failure.

Keep in mind that I am not saying there is no benefit from a tapered neck root. Rather, no evidence has been presented to suggest that a tapered root is any better than a perpendicular root in terms of handling  working loads and mild accidents. 

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6 hours ago, Urban Luthier said:

Of course this makes perfect sense David. I should have clarified above -- my curiosity is more around why many schools teach this 'restoration informed' method in new construction, when there may be other workflows for jointing a neck that are easier for students to learn and execute. 

I just looked at an old trade secret article by Howard Needham that illustrates the method for jointing a neck before the back is attached. I have never done it this way but I think I will give it ago in the future as a learning exercise

How else are you going to twist the neck on the plate pins and end up with assymetric sides and corner locations?

Somebody already said read Hargrave's acticles. Ditto!

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5 hours ago, David Beard said:

Somebody already said read Hargrave's acticles. Ditto!

I must be a dimwit as I have read that article a couple of times and could not understand it.

It must be one of those things that does not make sense until its put into practice.

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14 hours ago, martin swan said:

In a standard neck joint I can't see any genuine dovetail element ie. where the angled sides are directly impeding the forces of tension.

The dovetail on a well set neck adds a considerable amount of strength to the joint,  as it does in many forms of woodworking.  It is also why pearl slides that no longer have tongue extensions do not fall out of frogs....same concept.  You can readily see this in comparing how a neck feels when being set without dovetail ( you will be able to pull the neck straight up and out before glue) to a neck being set with dovetail, where one can lift a cello from the neck confidently before a drop of glue has been applied. 

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I suppose for me a dovetail joint is a very specific thing, in which matching angles (quite extreme) are cut into both joining elements. 

The neck joint on a violin is a slightly flared mortise. It doesn't resist any traumatic force, though if the sides of the top block mortise were longer then of course it would.

Since there are neck fits which use real dovetails (monstrosities in my view) it seems like it's worth making the distinction.

 

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7 hours ago, David Beard said:

How else are you going to twist the neck on the plate pins and end up with assymetric sides and corner locations?

Somebody already said read Hargrave's acticles. Ditto!

I'm quite familiar with Roger's articles ;). I Don't see any reason why a modern maker couldn't follow a variation of the  workflow employed by the ancients - in this case the neck is dovetailed to the rib garland rather than nailed to it. Then go about the workflow outlined by Roger in the Guarneri book to scribe the outline. The neck would need a notch of course to accept the top plate

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10 minutes ago, martin swan said:

I suppose for me a dovetail joint is a very specific thing, in which matching angles (quite extreme) are cut into both joining elements. 

The neck joint on a violin is a slightly flared mortise. It doesn't resist any traumatic force, though if the sides of the top block mortise were longer then of course it would.

Since there are neck fits which use real dovetails (monstrosities in my view) it seems like it's worth making the distinction.

 

Yes, the dovetail in a well set neck certainly adds to the resistance to traumatic forces (or all forces) because to have a failure, the block itself would need to fail, not just the glue joint.  As far as distinction, I do not really care what you call those monstrosities, but I fail to see why we would change the definition of ant word based on a few horrid examples.

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4 minutes ago, Jerry Pasewicz said:

Yes, the dovetail in a well set neck certainly adds to the resistance to traumatic forces (or all forces) because to have a failure, the block itself would need to fail, not just the glue joint.  

I guess I only have experience of poorly set necks then. They seem to part company with relative ease ...

My point is that violinmakers misuse the term "dovetail" which requires the deliberate shaping of two elements to form a joint, in particular forming a shape akin to the tail of a dove by removing stock from the tenoning element. 

But I'm fine with that - will try not to lose sleep over it!

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20 minutes ago, martin swan said:

I guess I only have experience of poorly set necks then. They seem to part company with relative ease ...

Exactly right, hence the dovetail.  Unfortunately, they will often take the button with them, and the ones you see that do not take the button with them is a further demonstration of why they should be be set with a dovetail..B)

No, it is not a misuse of the term dovetail because words have meanings regardless if you do not agree with the definitions or how much sleep you get.

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19 minutes ago, Jerry Pasewicz said:

Exactly right, hence the dovetail.  Unfortunately, they will often take the button with them, and the ones you see that do not take the button with them is a further demonstration of why they should be be set with a dovetail..B)

No, it is not a misuse of the term dovetail because words have meanings regardless if you do not agree with the definitions or how much sleep you get.

God Jerry you do love preaching.

Can you maybe do a little drawing of the dovetail element of your neck set? Maybe I'm misunderstanding ...

All I see in a regular neck set is a slight flaring of the neck root and a corresponding undercut in the top block mortise.

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This is a dovetail. The reason why it's called a dovetail is because the tenoning element is cut in the form of a dove's tail.

People misuse language in all sorts of ways. I will continue to put up a fight.

 

dovetail.jpg.2e01b23ffc8511388111c09cd1ed5c3d.jpg

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23 minutes ago, martin swan said:

 

This is a dovetail. The reason why it's called a dovetail is because the tenoning element is cut in the form of a dove's tail.

People misuse language in all sorts of ways. I will continue to put up a fight.

 

dovetail.jpg.2e01b23ffc8511388111c09cd1ed5c3d.jpg

Fight on noble warrior....then look at some reference material.  BTW, what do you call the joint for a pearl slide???

Are you now conceding the function of the dovetail but just having a problem with the name dovetail?  If that is the case I refer you to earlier discussions.  If you still have a problem with the reality of the usefulness of the dovetail, I am afraid I cannot help any more as you will need to just set a few necks and try it for yourself.  

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49 minutes ago, Jerry Pasewicz said:

Fight on noble warrior....then look at some reference material.  BTW, what do you call the joint for a pearl slide???

 

It's a tapered sliding lid, not a joint at all.

To understand a dovetail you just need to try making a few dovetailed drawers and try it for yourself. ;)

Re function, as I said the tapered element of the neck root is so shallow that it doesn't provide much strength, though it's definitely handy for controlling the fit. 

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19 hours ago, MikeC said:

regardless of angle this is what happens.  

neck.png

 

Edit:   or the button breaks.

Yes. The direction of the forces remains pretty much the same.

And what about trauma from above, when the head gets whacked from the opposite direction?

Although the only fails I have seen were from bad wordworking.

 

Bad wordworking, that's my best typo yet.

Edited by sospiri
typo

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14 minutes ago, martin swan said:

Re function, as I said the tapered element of the neck root is so shallow that it doesn't provide much strength, though it's definitely handy for controlling the fit. 

A diagram would help us idiots understand.

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16 minutes ago, martin swan said:

It's a tapered sliding lid, not a joint at all.

 

Describing the neck joint as "a tapered sliding lid" is a new one, for me. ;)

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11 hours ago, curious1 said:

Maybe it doesn’t really matter. And it’s a strong possibility I’m wrong about the whole thing. 

Necks aren’t the only things that fail.

Not wrong, it makes sense hypothetically but how much difference does it make?

11 hours ago, ctanzio said:

Keep in mind that I am not saying there is no benefit from a tapered neck root. Rather, no evidence has been presented to suggest that a tapered root is any better than a perpendicular root in terms of handling  working loads and mild accidents. 

If it's standard practice, then not doing it may be professional suicide?

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1 hour ago, Jerry Pasewicz said:

No, it is not a misuse of the term dovetail

Its the definition that you are putting on the long established use of the word "dovetail" which is being misused.

Here is a picture of my early 18th century walnut bureau. It has very crude dovetails with shoulders characteristic of the period. When it was made circa 290 years ago it would have been described as having  dovetail jointed drawers. They are clearly very different from the flared mortise - sans shoulders of a modern violin.

But it is a  fact that modern luthiers such as yourself have been taught to use this term in various schools and the idea has stuck.

rsz_dsc_0822.jpg

rsz_dsc_0825.jpg

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