Violin Forum/Message Board

KenN

I've never understood this dimension. If the overhang is 3mm how much further in does the neck go into the block. I've seen dimensions of 136mm for the neck that would suggest 3mm. That seems rather shallow to me. Why don't they just spell it out? I made the last one 4mm and that didn't seem deep.

Michael Darnton · Posted: Fri Apr 18, 2008 7:37 pm Post subject:

With a neck length of 136.5mm, and a margin (overhang) of 2.5mm, you should have 4mm into the ribs at the front. If you have the right angle on the bottom of the heel--around 87 degrees--the back of the heel will be 2.5mm deeper than the front, or a total of 6.5mm where it's really needed.

A 3mm margin is too large. Most good violins are at around 2.3 to 2.5mm.

KenN · Posted: Fri Apr 18, 2008 8:28 pm Post subject:

The neck goes in the block on a taper? That isn't pointed out in anything I've seen. The C and J book shows a 85 deg. angle on the bottom of the neck, and I just assumed it was equal to the neck angle, not double it.

Michael Darnton · Posted: Fri Apr 18, 2008 10:23 pm Post subject:

Yup. I'd say that 99.7% of the necks I've taken out were deeper in the back. Just look at that tiny bit of projecting neck-bottom under the board of any violin and you'll see it's sloping downwards towards the button.

KenN · Posted: Sat Apr 19, 2008 7:35 am Post subject:

I've never seen a sectional view of the neck thru the block. That's what I needed! Apparently it's just a given to a violin maker making a book, but they need to point it out. Maybe I'd better yank the Bergonzi apart and put a neck graft on it.

M_A_T_T · Member Joined: 03 Apr 2007 Posts: 43

KenN · Posted: Sat Apr 19, 2008 8:00 pm Post subject:

They made it more complicated than it needed to be. Why not make the angle at the top of the neck 90 degrees instead of 85 and just jut it further into the block? All three angles would be equal to the neck angle, that would be easy. Instead they have all three angles goofy. Oh well, I guess we have to do it the way it's been done for centuries.

Michael Darnton · Posted: Sat Apr 19, 2008 11:23 pm Post subject:

Don't fall into the error that things which you don't understand are wrong.The reason that it's the way it is is extremely elegant:

When the bottom of the heel sits on the uncut mortise, resting up on the unmortised edge, the backtilt of the neck is right, and the same as it will be when the neckset is finished. (I didn't point it out when I said it, but you'll notice the extra depth at the back, as I specified it, is exactly the same as the margin, as I specified it). All you have to do is sink it straight down into the block, conceptually. This helps you to visualize the proper neckset right from the start. It's not arbitrary, and it is helpful in getting things right. It's done the same with cellos, though obviously all of the numbers are different.

ollieken · Posted: Sun Apr 20, 2008 10:25 am Post subject: Neck Mortise

Micheal with the neck in deeper at the bottom of the block would that allow you to have the right hight at the end of the finger board without having a thick finger board ? I ended up with a finger a bit thicker than i wanted made the angle acording to the book . I did not see that in the Stroble book on the angle . Thank you for sharing Ken

KenN · Posted: Sun Apr 20, 2008 11:05 am Post subject:

Thanks for pointing that out Michael. Now it makes sense. I enjoy learning on my own but sometimes it just doesn't click. Things are a lot easier to do when you know why and not just that they are.

Andres Sender · Posted: Sun Apr 20, 2008 3:00 pm Post subject:

Ollieken--As I understand it, what Michael's talking about is simply an efficient way to get the correct neck angle with a good strong joint. It's not directly about controlling fingerboard projection.

For a given angle of strings over bridge with a given action height, the neck needs to be at a certain angle, ideally (i.e. for ease of fitting) this would be set up by the way the angle of your neck root relates to your overhang at the mortise position.

Given the correct neck angle, having the right fingerboard projection is generally (i.e. for the normal range of arching heights) a matter of matching your overstand to your arching height via relating the fingerboard projection (at the correct neck angle) to an ideal bridge height.

ollieken · Posted: Sun Apr 20, 2008 8:31 pm Post subject: Neck Mortise

Andres Thank you for the reply The bottom of the neck to fit it to the plate is it the same angle exact as the long angle say 83.5 had a hard
time with this finaly got a good fit This is my first had a pro & recoring artist try it out he said it has good balance lots of voloum fast response
& said Ilike it I had a hard time getting my head in the car door it was so
big just got lucky i guess .If not for this forum it would not have turned out that good so thank you all for advice & putting up with us new guys
Ken

JWH · Member Joined: 26 Mar 2007 Posts: 72

That neck root angle and it's relationship to the finished angle which Michael is referring to can be determined trigonometrically. An example would be using the distance in height of the ribs and the width of the margin to determine the opposite and adjacent sides of a right triangle which then can determine the angle of the root.

If, for example, the rib height is 32mm and the margin is 2.5mm wide intersecting at 90 degrees, then the sides b/a or 2.5/32 will give us a Tangent function of .0781 and a corresponding angle of 85.5 degrees.

Obviously, if these measurements change independent of each other, as in say, 30mm ribs and a 3mm margin, then the root angle will be different to accommodate the same neck angle.