Violin Forum/Message Board

[famuswood]

I have undertaken the project of replacing the neck of my brother's 1921 German Strad copy cello with hollow corner blocks. I intend to graft the existing scroll to the new neck. The scroll has Roth Caspari pegs and a repair of the neck has been attempted in the past. When I removed the cello belly and neck, I discovered a rectangular stick of maple had been cut through the base of the top block about 1/2 in thick and the length of the top block plus the shoulder thickness and screwed to the base of the repaired neck. My first question is, should I be confident that a neck replacement with a proper fitting and good glue up be sufficient or should I go further with an added screw or dowel inserted through the base of the top block. The second question: is it more difficult to graft a neck on a scroll with Caspari pegs. Also - does anyone know the taper of a Roth Caspari peg and peg hole. By the way, I removed the top to insure there would be a good glue joint on both the belly and back plates. There was quite a bit of movement going on at the shoulder and I wanted to be sure it wasn't the top of the top block.

Just thought of one more issue: The back plate tab was previously destroyed and just pieced back together, therefore serving no strengthening bond coming from the back plate. That may have played a part in the added stick of maple. My intention is to cover the tab area with an ebony button extending over the broken area and extended a little further down to hide a little crack in the back.

Thanks for any thoughts. . .
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I love the feel of wood in my hands - the smell of fresh cut lumber and the challenge of a difficult woodworking project on a sunny day . . .

[FiddleDoug]

Photos please. Sounds like the button has been destroyed and someone kluged together some kind of repair. If you want to include the Caspari pegs in the final, you may have to figure out how to remove the friction bushings from the peg head side of the peg box. The Caspari pegs may be a straight hole, don't remember for sure. Never had to drill one.
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Doug Wall

www.wallindependent.com

[famuswood]

Here are some pics of the cello. My primary concern is a solid neck joint because of the significant string pressure on this rather delicate instrument. It has been around quite a while and has had some significant issues develop along the way. The top block appears to be solidly glued at the back plate and ribs. My only concern is following that up with a solid fit and glue-up of the neck and top plate. Secondary to that I intend to cover the button area with ebony or perhaps rosewood grafted into the the back plate and button area. Thanks so much.


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I love the feel of wood in my hands - the smell of fresh cut lumber and the challenge of a difficult woodworking project on a sunny day . . .

[L P Reedy]

Maybe I'm not seeing everything, but it looks to me like it would be much simpler to do a good repair on the existing neck (after grafting a new button) than to graft in a new neck. As Doug hinted, the Caspari bushing for the C peg may be a bit of trouble to remove and replace. Are the pegs the reason you want to keep the scroll?

[Michael Darnton]

I don't see a clear shot of the neck heel, but what I think I'm seeing here is
a common way to fix a broken button. Basically, it involves grafting a new
button-like extension inside the broken one, running down into the block
between the block and the back. Then the neck is glued to that instead of
the broken button. The button, broken off, doesn't have any strength, so at
that point it's just decorative. In this case it looks quite a bit over done--
usually the added piece is only 2 or 3mm thick, not a good half inch like the
one in the photo.


The classy way to do the repair is to glue the button back on to the back,
and then do a "bathtub" patch on the inside of the back/button, half on
one, half on the other, to tie them back together by replacing most of the
broken wood from the inside. It can go pretty deep and wide, but doesn't
extend out all the way to the edge of the button, so it's invisible.

Does that make sense in this context?

By the way, if I'm remembering correctly, the Caspari reamer is tapered
on the thick end, so that the fiber bushing will wedge in place, and has no
taper on the small end, so that end can rotate freely. It was a single-use
aluminum thing, and one came with every set of pegs.
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[FiddleDoug]

Clean up the existing neck heel. Add maple blocks to the neck heel where appropriate to get the height and depth correct. Remove the existing neck block. Do an appropriate button graft. Add a new neck block, and do a neck set into it.
_________________
Doug Wall

www.wallindependent.com

[famuswood]

Thanks to everyone for your ideas and suggestions . . .

To give you a better picture of what is going on with this cello: The neck has a break that runs lengthwise basically from nut to heel. It runs about 1/4 inch below the fingerboard parallel to the fingerboard. A poor repair attempt has been made that you can actually see in the shot I sent if you look closely. The entire neck should be replaced. The existing button is cracked and broken in two pieces. There is not a clean break where the button was reattached to the back after the button tenon was installed. it was basically placed next to the back where it was originally attached.

So Michael - do I understand you to say that another maple mortice, two to three mm thick should be created through the base of the top block with a tongue/tenon that extends to the button area over which is placed the hollowed out existing button? That does make a lot of sense if you think with a proper fitting replacement neck there is sufficient strength to keep the neck in place with string tension.
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I love the feel of wood in my hands - the smell of fresh cut lumber and the challenge of a difficult woodworking project on a sunny day . . .

[FiddleDoug]

If I remember correctly, they show that type of button repair very nicely in my Weisshaar & Shipman. As far as the neck goes, with the fake corner blocks, it's probably a German factory cello. Not sure the expense of making, or buying a new neck is worth it. An alternative might be to remove the FB, and cut a couple of slots for carbon fiber splines or rods in the neck. Epoxy them in, put the FB back on, and it's stronger than the original.
_________________
Doug Wall

www.wallindependent.com

[Michael Darnton]

The bathtub patch fits completely within the back. It's even with the inside
gluing surface of the back on the inside, and sinks into the back about 2 or
3mm into the button and gluing platform in a bathtub shape. It doesn't stick
out into the neck/block area at all. Somewhere I have a sketch I did of it
that I can't find at this moment. . . .
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[famuswood]

Yes, I think I understand what you are saying. I realize that it is contained within the button and not showing anywhere around the button. So the button looks like any other button without any repair. Still, the patch needs to extend beyond the top block and is glued to the base of the heel, correct? Otherwise, it would serve no strengthening value to the neck. I hope I'm getting this right. My only question is how to accomplish this without loosening or removing a portion of the back, unless you create a mortise from inside the back as the overly thick one in the picture, to the button area of the heel. I hope this makes sense to you. Thanks
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I love the feel of wood in my hands - the smell of fresh cut lumber and the challenge of a difficult woodworking project on a sunny day . . .

[famuswood]

Ordinarily, I guess replacing the neck may not be warranted on this instrument, but it has been in the family since we were were very young and was the instrument my brother played in school. I would like to see it looking as good as possible. To leave the existing neck with the poorly reattached break in the neck is what we are trying to avoid. The effort it would take to get it looking decent might be more work that a new neck and fingerboard would require. I may not attempt a graft of the scroll if the Caspari pegs are going to complicate things. My original question when I started this topic is: Does a broken button necessitate reinforcement by other means or does the lack of button reinforcement mean the neck might not hold, even if well fitted?
_________________
I love the feel of wood in my hands - the smell of fresh cut lumber and the challenge of a difficult woodworking project on a sunny day . . .

[famuswood]

Just to communicate with you who have been contributing to these posts. I finally got it through my dense head that the patch is entirely resident in the back plate, only extending from the top block to the button, hidden within the block/button area. Michael was patient with me and sent that sketch he had mentioned. No mortice needed.
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I love the feel of wood in my hands - the smell of fresh cut lumber and the challenge of a difficult woodworking project on a sunny day . . .

[Jack H.]

Ok, so maybe I am not seeing everything, but it does not look like the neck needs to be grafted. Just reset. the button is missing and needs to be doubled or a new one needs to be made. the tenon coming out of the upper block looks like a way to reinforce the old button. WHat needs to be done now, is
1 glue the old button in place.
2 make a plaster / bondo mold of the button area.
3 the button needs to be doubled.
4 the mortise needs to be filled in a bit on the sole area and the sides.
5 the neck needs to have a spot of wood glued onto the back of it if needed to help in re-setting the neck.

Make measurements before cutting so you know how much wood you need to add, remove to make the neck come out nice and straight, with the right angle and proper A-C tilt.

Jack Havivi
Havivi Violins
Israel

[famuswood]

The scroll right by the nut area would break off with very little pressure. It is more compromised than it looks in the picture. I have a feeling the neck does need to be replaced. All things considered, it would be more trouble than it is worth to try to brace these areas with splines and other means. I don't know if you read all the previous posts but the neck was poorly re-glued and has a major crack the length of the neck. The only question I have at this point is whether to attempt a graft of the existing scroll to a new neck or carve a new neck and scroll. I had question about the difficulty of grafting to a scroll with Roth Caspari pegs. One response stated that it might be hard to gracefully remove and refit them. Still, I would certainly welcome your thoughts and ideas. Thanks so much.
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I love the feel of wood in my hands - the smell of fresh cut lumber and the challenge of a difficult woodworking project on a sunny day . . .

[famuswood]

I am not a highly skilled luthier but do love the challenge of making and repairing instruments of the violin family. Below is a picture of the aforementioned cello I sought to repair for my brother. It is the instrument he played forty plus years ago in high school. I ended up repairing a bass bar crack by inserting four cleats under the bass bar. The existing bar was a little short and very clubby. I reduced it in thickness from approximately 15mm to a little over 11mm. The top plate was quite thick so I reduced it somewhat but not at thin as is recommended on new instruments. I purchased a neck with a pre-carved scroll, used the existing fingerboard. I know using an orignal fingerboard is discouraged but saved cost on a lower quality factory made instrument. The button had been repaired once before and was mutilated beyond repair when the neck was broken this time. I did a four inch graft of a new button from the inside of the back. I tried to match the existing finish as best I could. I know it isn't stellar but pretty close. The Wittner pegs went in quite easily. and the neck is secure with strings at full tension. My brother said the cello had a wolf tone problem. I could not find any wolf tones anywhere on the instrument. Thankful for that. I think the cello sounds very good. I really appreciated the helpful comments I received on how to proceed with this instrument. Thanks so much.

https://picasaweb.google.com/chumn54/GregSFinishedCello?authuser=0&authkey=Gv1sRgCP_Fzv74lbvyhAE&feat=directlink
_________________
I love the feel of wood in my hands - the smell of fresh cut lumber and the challenge of a difficult woodworking project on a sunny day . . .