MIMF

I'm trying to clear by bench of a few ongoing projects and this one seems to have worked it's way to the top of the list.

It's an old Tone King Mandolin, I'd guess made by Regal but would love to hear anyone's thoughts. After replacing back braces and kerfing then re-glueing the back, I find that it is in desperate need of a neck re-set. Has anyone ever torn into one of these? Would it have a dove tail joint and if so, could I proceed as it it was a guitar neck re-set (pull a fret and shoot steam into the neck pocket)?

I'd prefer not to pull the fingerboard if I can avoid it.

I'd appreciate any thoughts anyone could share.

The Back/neck heel

Where was it made? If Chicago it should be a dovetail. If the Orient not even a guess.

Hi Mike,

I'd put it around the 20s to late 30's and Chicago. Mahogany back and sides, Adirondack Spruce top. It's clearly old and has detailing similar to other Regals of the era. Assuming a dovetail, I'd think I should be able to pull a fret and drill for the pocket.

I agree, I believe that to have a dovetail.

Yes, it was a dove tail. It had an incredibly brittle fingerboard I did manage to get off but not without damage. I assume from the age and quality that this was an "ebonized" finger board. Anyone know why these things are so delicate?

I have found that before as well. Some of these old fingerboards just literally crumble if you try and do anything with them!

Many old cheaper fingerboards were stained dark or ebonized with acid or some other chemical, which does a job on the cell structure of the wood. Many of them just crumble and flake if you try to disturb them. There is very little one can do for them when they are like that. You can try to glue the pieces back where they came from but if you want to play the instrument much the fingerboard should be replaced. Actually, that fingerboard doesn't look all that bad, it is still in mostly one piece.

Yes, I was able to saturate it in superglue as it started to crack. It did break at the 12th fret, but I was able to glue that entire section back on with titebond.

That acid comment makes very good sense. If I were to guess, I'd say the fingerboard almost looked like sycamore with fine grain and delicate cross hatching. It looked better than most "ebonized" fingerboards I've felt with but clearly, I was wrong!

OK, now on to the neck re-set. Based on Dan Erlewine's neck re-set dvd, the formula for a flat top is:

X = A X B divided by C

X = the amount of wood to be removed from the heel, B = the length of the heel from bottom of fretboard to bottom of heel and C = the distance from the neck joint to the center of the bridge.

Is this the same for a mandolin? The bridge is a solid floating bridge with a saddle. Thanks!

What is "A" then?

Opps. Sorry, A is the distance needed to move the point where a ruler sitting on the fret board currently meets the bridge to where it needs to be to meet the bridge correctly. Based on Dan's DVD, I'm assuming 1/8" saddle above that.

Here's the bridge. Pencil mark is approx where a straight edge currently sets the bridge. I'm measuring to the bottom of the bone saddle inset as the distance I need to change the neck angle, about 7/32.

OK, I've measured everything and converted fractions to decimals and here's the formula I get:

X = A X B / C

OR .219 X 2 / 7 WHICH = .06257 OR .063 to shorten it.

Of course, this is based on the acoustic guitar formula, but I hope it will get me in the ball park.

Here it is taped up and ready to cut. I'll give it an hour or so in case anyone has any words of wisdom to offer before I start cutting!

Thanks

OK, I went for it and am pleased to say it went fairly well despot the wood be soft and "punky". Looks like Mahogany, but doesn't seem as strong. Here it is being glued up. I used hide glue for the first time and it all seemed to go well. It did raise the fingerboard extension up a bit but I'll shim it tomorrow if need be.

Mahogany looking wood that is soft is probably Spanish Cedar. It tastes awful!

For figuring out neck angles for a mandolin I use a straight edge on the fingerboard to project to the bridge, and when it is the correct angle the straight edge should be about 1/8" (3mm) below the top of the saddle. That gives you 1/16" (1.5mm) clearance of the strings at the 12th fret which is a nice action height.

Chris Vallillo wrote:C = the distance from the neck joint to the center of the bridge

how is that exactly? is it actually to the center of the saddle? or do you actually go to the "center of the bridge?" that doesn't quite make sense to me because a guitar bridge can be all varying sizes depending on the design of the guitar and bridge itself. So what exactly is the "C" measurement?
And if it's to the center of the saddle, at what point to you measure since most SS saddles will be compensated?

I'm sure it means "to the center of the saddle." Down the center line of the neck to the middle of the saddle. This is just to establish a center line for the rest of the equation to work.

Thanks Mark. That was the only way that made any sense to me, but the wording was throwing me off. Now I get it.