Official Luthiers Forum!

I'm about 3/4 of the way to un-recommending Siminoff as a mandolin
construction manual. Having built a guitar with Cumpiano by my side,
this is a sad comparison.

My current frustration is that I can't find in the text many descriptions of
the dimensions of the neck, and the drawings have proven to be too
inaccurate to be reliable. I'm not a mandolin player (yet), so I'm not
familiar enough with mandos to "wing it".

Some of the questions I have in particular:

How wide is the nut?

What is the thickness (as opposed to width across or height above
fingerboard) of the nut? I'm guessing something around 3/16" of an inch.
1/4 just looks too "fat".

Approximately how far does the button on the bottom of the neck
protrude from the rim on either side of the button? Does it matter at all
in terms of playability?

How wide is the neck at the 15th fret? I'm looking for a reference width
further down the neck so that coupled with the width at the nut, I can
establish the taper of the neck/fretboard.

(Approximately?) How high should the top surface (freboard plane) of the
neck be above the top plate at the 15th fret? Alternatively, how thick is
the fingerboard extension at the 15th? I'm still trying to wrap my mind
around Siminoff's neck alignment fixture and how the neck fitting process
works with it.

Does anyone know if the depth of the neck profiles in drawing 2 include
the fretboard or not?

Thanks in advance for your help and wisdom. My apologies if I've missed
anything obvious - please don't assume I've caught something that's in
24pt bold italic underlined letters ;-).

Jay

Jay, sorry that i can't be much help at this hour, i'm away from the shop right now. One word of advice i have received from Arnt was to forget about the plans and dimensions of the Siminoff book because of the inacuracy of their plans and rather use the LMI plan which is much closer to Loar's F5 mandolin and more acurate. Siminoff's book is rather used as a build guide like C&N is for building guitars, hope this helps a bit.

Thanks for passing on the tip, Serge! I just jumped over to lmii.com and
they have two plans, one by Don MacRostie (described as "F5-style
mandolin") and one by Ted Davis (described as "1923 Lloyd Loar Gibson
F5 mandolin"). I assume you're using the latter?

Hi Jay, get the Don McRostie plan, it is very good. The Ted Davis one I have heard has some inaccuracies. The only drawings out there that is probably better than McRostie's is this set of GIBSON LLOYD LOAR F-5 MANDOLIN PLANS drawn by Adrian Minarovic, they are very faithful to Loar specs if that is what you are interested in. I don't have them, but everybody over at Mandolin Cafe are very enthusiastic about these drawings.

My McRostie plans show a 28 mm (1 1/8") nut width. As long as we you are talking about the neck, make sure you cut the truss rod slot before you profile the neck, NOT as Siminoff suggests, which is the opposite.   

How far into this project are you?

_________________
Rian Gitar og Mandolin

Arnt answered better than i would have Jay, i use the first one as per his advice!

Thanks Arnt.

I'm not trying to build a replica of a Loar - to start with I'm using materials mostly on hand (i.e., mahogany). I'm further adapting Siminoff's plans to an A-style by omitting the points and scroll. But not having dimensions listed on the drawings is driving me nuts!

As to how far I am
- I've got top and back plates rough carved (and paranoid about carving them too thin),
- I now have the neck blank rough sawn,
- head and tail blocks cut out.
- I've got a practice Sapele guitar side that I'm going to rip and use for the rib - might try to bend that tonight.
- Got some ash that I'll make kerfing and maybe bindings out of.
I got a set of schaller tuners and an ebony bridge last birthday, so that's taken care of. Have an ebony head plate that I'm going to use. I'm going to have to buy a fretboard.

We'll see how this goes...it's either going to be beautiful or an utter disaster, but either way it will be unique ;-).

OK, good! Don't carve the plates any more until you have the McRostie plan. Then make arching templates from it and use those to guide your final carving of the plates. The Siminoff templates leave a lot to be desired.

I made an A-style adapted from the Siminoff plans too. Neither mine nor the Siminoff body outlines are true to Gibson specs, but this is not a problem unless you stray so far from the original that you cannot find a case for it...

_________________
Rian Gitar og Mandolin

Hey Jay,
I built 6 mandolins before Siminoff's book and it helped me a lot. But now, about 7 later, I notice a lot of things you mention to be inaccurate or difficult to render in 3-D.

The nut is usually about 1 1/8 inches. Some go up or down 1/32 from that, but 1 1/8 is pretty much standard (from my experience).

I don't have the book with me, so I'm not sure what "button" you are referring to. If it is the extra piece of mohogany through which the 15th fret cross piece goes (part of the fingerboard extender), then it stops flush with the rims and curves down to about 1/8" above the rims at the edge.

For the neck width I use, and I'm not sure if it is consistent with Siminoff, 1 1/2" wide at the 12th fret. You could probably use that at the 15th as well, or maybe slightly larger, but that is the neighborhood. The neck width is all a personal decision, but that will get you close, I think.

How high the top of the fretboard is above the top plate will be related to the neck angle you use. I have used the top of the neck (bottom of the fretboard) as 3/8" from the top of the *rims*. Adding ~1/4" for the fretboard would land you somewhere around 5/8" from the top of the rims to the top of the fretboard. That is using a neck angle of about 6 degrees (maybe slightly less). It has worked for me. The bottom line on that, from my end, is to get the plane of the fretboard to land about 3/4" above the top plate at the bridge location.

Again no book, but the profile in drawing #2 would show the fretboard if it is there. I can't honestly remember, but I do not think it includes the fretboard. Either way, cut just about everything slightly larger and trim down as you start putting things together.

I hope that helps. I taught my first mandolin building class this last semester and tried to go by Siminoff's book, but ended up teaching my own way. I guess that is how it goes--to each their own. And I hope you find your own way happily!

Jay
Having made a mandolin as my first instrument from the same book, I share your pain. The second I made was a guitar- but that is altogether another story. I have the instrument here & will try & answer some of your questions:
1. The nut on mine is just over 1 3/16" wide, about 5/32" thick and 5/16" deep- actually a little too deep as the strings are burried in the nut- I figured I could file off the extra, but just have not ' gotten around to it'. Keep in mind that my fingerboard is around 3/16" at the edge & is radiused 12"
2. Approximately how far does the button on the bottom of the neck protude & does it affect playability The protruding button by the neck heel on my mandolin-is about 3/8" & it is a part of the back of the mandolin- somehow I did something wrong in cutting the neck join somewhere & actually had to add a 3/8" segment to the bottom of the neck heel to get rid of the gap between the bottom of the neck heel & the back of the mandolin-- it added an interesting visual element to the area, but did not change anything as far as playability-- Mine is the f5 version with the points & scroll, so the button might get in your way if you "play way up there" on a modified instrument.

3. How wide is the neck at the 15th fret?
the width at the 15th fret is close to 1 7/16" and is 1 1/2 at the 12th

4.How high should the top surface (freboard plane) of the be above the top plate at the 15th fret
Mine is about 7/16" +/-

5. how thick is the fingerboard extension at the 15th?Mine is about 3/8" +/-

6. neck profiles It's my guess that the neck profiles shown in his book would include the fingerboard-- The reason I guess that is that my neck came out about 1/4" too thick according to my mandolin playing friends. When comparing my instrument to their manufactured ones, their necks are considerably thinner than mine. I have large hands & have gotten used to the neck on my mando. You could cut to the templates & then shave down before finishing to something you like (I'm assuming this mando is for you?!)
BTW-- the neck to body join (with dowels) is what I used, as I was clueless in making the dovetail joint. It has been described by others in other forums as "doomed to failure" and " would be a nightmare to reset the neck". I have had no failure problems with this neck & my mandolin is nearly four years old & has continually been strung & played at least weekly since. Hope these comments have helped.
Phil