My Old Kentucky Neck

[Kennyz55]

Bought this Kentucky mandolin with a broken headstock. Repaired it a few different times and the repair failed after some time each time. Now I want to make a new neck. How do I cut a new dovetail into the head block without ruining the back or should I cut through the back and leave the new neck's dovetail exposed.

[MikeEdgerton]

Take the back off.

[fscotte]

Clean out the dovetail area and fill it with a new block of mahogany. Take the back off as well. Then proceed as normal making a dovetail joint. It won't be easy.

[Kennyz55]

I wrote John Hamlett, Sunburst, before I started this thread and he said "No, I would not remove the back. In the picture, it looks like a straight dovetail, and I much prefer to use a tapered dovetail. I'd just cut a taper into the block; widen the mortise at the top so that there is a taper.". Thanks for all the help.

[MikeEdgerton]

If you're not going to remove the back then you can modify things a bit "if" you end up cutting through the back. I believe that on that Kentucky the end of the heel is covered by the back. On some mandolins they use a small heel cap to cover the end. You could always simply remove the heel cap portion with some careful work and plan on making a cap.

[sunburst]

Since I've been mentioned here...
Things go wonky when we remove the back. Damage is always a possibility when removing a top or back, and re-alignment can be difficult. If I don't absolutely have to remove a back I prefer not to.
Most repairmen have fit lots of dovetail (and other) neck joints that are not through mortises. Every time we re-set a guitar neck we do it. Removing wood from the head block down to the back surface is all that would be needed to rebuild the head block. I would probably do that, and when I got to the back, I'd scarf in a piece of maple to replace the heel button. Taper the sides of the cavity in the head block, chalk fit a piece of mahogany (with dovetail mortise pre-cut), and then re-set the neck.
I still have the photos somewhere that were formerly posted on my website where I did a similar repair to an early Gilchrist mandolin, and I've since done a similar repair to a Kentucky, oddly enough. Some may remember the photo-essay of the Gilchrist repair. I saw that mandolin again last month, and it is still holding fine and still showing little evidence of repair.

[Kennyz55]

I would love to see those pictures John and sorry if I quoted your personal email without approval.
Additionally,
What you use to remove wood from the head block, tool wise?

[Kennyz55]

Back at it again. Happy Easter all.

[sunburst]

...What you use to remove wood from the head block, tool wise?

Missed this...
I used a dovetail saw and chisels to cut the mortise in the head block. I sawed the dovetail into the new wood before gluing it in place; much easier that way because we can use a saw and work all the way through.

[sblock]

Very nice! But is this fabulous effort turning into a $1,500 repair on a $1,500 mandolin? Still, I suppose the heart wants what the heart wants...

[Kennyz55]

Starting to come together slowly. I think I paid $150 for it with the broken neck and with the 1727 hours in at minimum wage that's only $14472.26 in it so far. NJs minimum wage is $8.38. LOL.

[Kennyz55]

What advantage is a tapered dovetailed Neck? How would I lay it out on the head block? I have this from Roger Siminoff to layout a non-tapered dovetail joint. http://siminoff.net/cms/wp-content/u...d_dovetail.pdf

[Kennyz55]

If at 1st you don't succeed just keep trying.

[Eric Oliver]

I don't know. Maybe you get the award for the most dogged and determined effort at repair?

I like your sign-off quotes.
You strike me as a Ken Kesey, Sometimes A Great Notion quote: "Never give an inch."