Upper cap on headblock

[MandoDiddle]

I have some questions concerning the upper cap on the headblock (the part that is in front of the fingerboard extender).
The tail side of the of the upper cap is staight and has a celluloid strip that is supposed to be under the 15th fret. (I hope I am correct in this assumption.)

These are the questions I have:

1. This upper cap is supposed to be glued to the headblock before the dovetail is cut into the headblock. How can I line up the celluloid strip side at the correct distance and angle that matches the 15th fret if the neck has yet to be fitted?

2. Is the space between the end of the dovetail on the neck and the female dovetail cut in the cap/headblock supposed to line up under the 15th fret so you can take out the 15th fret, drill a small hole in the in the exposed fret slot and be able to steam out the joint? Or, can the space be located under the inlay marker for the 15th fret?

3. I am using jigs to make the dovetail on the neck and headblock that Don MacRostie uses on his mandolin building tapes. It seems that I can only get a 1/2"x1/2"x 14 degree dovetail bit. The problem with this is that I can only get a dovetail that is 1/2" deep, which seems smaller than most others that I've seen. Is this 1/2" depth OK? Should I extend by hand with chisels? Is there a 3/4"x3/4"x 14 degree bit out there that I could use?

I know this is a lot of questions, but I really could use some help. Thanks in advance.

Bill

[Chris Baird]

1. #You are going to have to know the distance from the nut to the end of your dovetail if you want the bridge and neck to be in proper position. #After you ascertain how far from the end of your dovetail the nut will be you can then figure out where in relation the 15th fret will be on the headblock.

2. #It would be considerate for you to plan to steam the neck out without having to take the fingerboard off, but, I don't think it is realistic. #Resetting a neck will almost certainly involve taking the fingerboard off so I wouldn't even worry about it.

3. Yes, you can find nearly any dovetail bit you could think of. #Surf around on the internet and buy exactly what you want. #Don't let your local hardware store limit your mandolins potential.

[bobz]

Hello Bill,
I went the Don Macrostie route by cutting my dovetails using his method. My problem was the other way round in that I could only get a 1/2 inch depth to my dovetail because of the length of the rabbet cutters I modified for my moulding block. I opted for a 10 degree angle router cutter because I already had one. I think you`ll find a half inch deep dovetail is plenty strong enough.
If you`re working from the Macrostie plans, just take the measurement of the 15th fret crosspiece from that. To get the length of your neck, make a test neck, fit it your mando body, and with a rod with the nut and 15th fret positions marked on it, lay the rod on the neck with the 15th fret lined up with the 15th fret on the body. Then mark on the rod the end of the dovetail of your test neck. The distance from this mark to the nut mark is the length of your neck. Remember to allow 3/16 inch extra for the nut.

[Jim Hilburn]

The key is the 14th fret. This is because it's common to both the neck and the body.
On the body, you need to find the 15th fret using either the end of the body or projected bridge location. Subtract 1/2 of the width of the binding strip and that's where you saw through the top, and when you glue on the riser, it should locate the binding strip center on the 15th. After gluing on the riser, you need to mark the 14th on it, and use the fingerboard to mark the 14th on the neck.
On a piece of paper, draw a centerline and a 90 degree crosshair line in the center. The crosssing line represents the 14th. I draw a long line on my bench and tape the paper so the its in line with the center. This is so the centerline goes all the way to the butt, or you could use a long piece of paper. Now you can align the mandolin body with the centerline and the 14th. Draw the nose onto the paper.
Now draw the dovetail, whatever shape and depth you want onto the paper. That's the whole layout. Now you can use an Exacto to cut along the lines of the nose and dovetail, and you have a template to carefully tape onto the body, and the other side onto the neck.

[MandoDiddle]

Chris, Bob, and Jim,

Thanks so much for the replies. This forum is great and I really appreciate the time you guys take to answer questions that you have already dealt with in your journey.
I think I can use all the information. It makes so much sense once you see it.

Thanks'

Bill

[Darryl Wolfe]

Another method..and a good one for dummies...is to cut the dove tail in the body....then cut and fit an unprofiled rectangular neck blank to it at the proper backset......THEN figure out where you want the nut position and peghead break to occur at

[Darryl Wolfe]

now of course I'm referring to me as a dummy...not you

Darryl http://www.mandolincafe.net/iB_html/non-cgi/emoticons/mandosmiley.gif

[MandoDiddle]

Another great idea Darryl.

Thanks'

Bill

[RI Jim]

Hey Darryl, it's funny you should mention that. A very well known builder in the area does just that, it looks like he's fitting a 2x4 to the body, but when the dovetail is right, he goes about laying out the neck. That's one of those ' bop yourself on the head ' and think ' how come i never thought of that ' !

Jim Combra

[sunburst]

That can be trouble.
I have fit dovetails with necks that were left big only to find that the fit changed after the neck heel was shaped the rest of the way.
Unless you have a near perfect fit everywhere between the heel of the neck and the rim (head block) of the mandolin, the dovetail will likely fit farther in and can change alignment after carving the heel the rest of the way. This is especially true if you undercut the neck like the normal tendency will lead you to do when you're trying for a good tight line where the neck meets the body.

I get my best results by shaping the heel area of the neck completely and even sanding it nearly to completion before I fit the dovetail all the way.
For F5s there's another advantage to finish-sanding the neck heel, headblock area, and the neck side of the scroll before installing the neck. It's sure easier to get to those parts to sand them before they're put together about 1/4 inch apart!

[edit]
I got to thinking I should mention the fact that this method requires that I keep my center lines nearly perfectly aligned, and neck angle very close to where I want it during the neck setting process.
The 15th fret position doesn't have to be perfect, however, if I havent shaped the peghead yet.
I just leave the neck a little long and after the dovetail is done, I can lay the fingerboard on the neck with the 15th fret in the proper position, mark the position of the nut, choose my nut width, make a second mark for that, and surface the face of the peghead 'til the line of intersection of the two surfaces is at that second mark.

[MandoDiddle]

Does anyone know the historical significance of the celluloid strip on the headblock cap lining up with the 15th fret? Was there a practical reason for this relationship?

[Chris Baird]

It connects the binding from the top to the fretboard. It is purely cosmetic.

[sunburst]

That binding piece goes back to the old Gibsons without fingerboard extenders. The fingerboard was glued to the top and to the "upper cap" with the binding piece serving as a transition. It didn't line up with the 15th fret until the F5, and it's sort of a vestigial ornament.

[Darryl Wolfe]

Sunburst..maybe I should have added to profile the heel taper a bit so that you can see what you're doing, but don't do the side profile until you arrive at a fit
http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif http://www.mandolincafe.net/iB_html/non-cgi/emoticons/mandosmiley.gif

[Darryl Wolfe]

Like this..which is still a rectangular blank otherwise

[sunburst]

Darryl, Man! you sure have big pictures! (Ther're still trying to work the bugs out of my high speed connection.)
That fit looks great! I like to have mine a little closer to finished, but that doesn't mean everybody needs to do it that way.