Center line and neck dovetail offset... Am I in trouble?

[putnamm]

I constructed all of my current F5 templates--body and neck--as well as my jigs (truss rod slot cutter, neck dovetail jig, body dovetail jig) with the center line of the body and the neck running dead center from peghead to tail pin...

...then looking today at photos from several renowned makers I notice the (what I believe is a Loar practice) "offset dovetail" on the neck? The dovetail is cut more to one side than the other. In looking back at the Siminoff book I see this is noted, as well. But I did NOT do this on my one and only build. And it seemed to turn out fine...

Is this standard, or even required to make a proper fit? Am I in trouble, and do I need to remake all of my templates and jigs??

[rcc56]

I'm a repairman, not a builder, so I can't say anything for sure.
But it would seem to me that as long as your bridge ends up centered, and the neck doesn't end up at an odd angle, you should be ok.

And I'll offer the following question: Was the deviation from the centerline in early F-5's intentional, or was it an error in tooling at the factory?

I'll also mention that I have seen some older Gibson guitars that deviated from the centerline by as much as 1/8", but I don't believe that the deviation was intentional in those cases. It did add to the labor time on a Roy Smeck conversion that I did a while back.

[jim simpson]

The offset shouldn't be a requirement as long as the symmetry of your design is pleasing. The alignment to the tailpiece is, of course, very important.

[amowry]

I've always centered my neck on my F5s. I realize some purists may frown on this, but I prefer the appearance of having the little curved sides of the fretboard extender the same width on each side. The opposing view is that if you shift the neck toward the scroll a bit, the space between the scroll and the neck is roughly the same as the size of the opening in the scroll, so there's visual continuity when you follow the scroll opening up along the neck. Either way, it's totally visual, and 95% of people won't notice it.

Edit: I just noticed, if you look at an Ellis mandolin (like the ad/photo that is currently at the top of this page), they do the same thing that I do, centering the neck so equal amounts of the fretboard extender are exposed on each side of the neck, leaving more space between the scroll and the neck. I think that looks better than the Loar way (sacrilege, I know!).

[Timbofood]

The offset shouldn't be a requirement as long as the symmetry of your design is pleasing. The alignment to the tailpiece is, of course, very important.

I fully agree with you Jim, if the “line is fair” and pleasant (and it does not make YOU crazy) go with it. There are myriad builders NOT using the original “offset” neck design. But that said one must raise the question: “Is it an “F-5”? “? Where the original design is the benchmark(definition) are the subsequent interpretations no longer “F-5’s”? But, “homage” to the design.
I am not so much the connoisseur to (generally) go off the rails when it’s not “Right” as long as the interpretation is visual (and totally) pleasing.

So, if the design and sound is what you are looking for, build!
There are always little things that put me “off” about some but, they are based in hours long conversations with highly regarded builders.
The one that really makes me cringe is when someone makes a really well built “F-5” and does not appreciate the ever so gentle “tumble home” return on the treble point. When it’s just stuck out there like an abusive middle finger, I can’t even pick them up!
Call me crazy but, the finesse and artistry of the design is both “in your face” but also in the delicacy.

[HoGo]

Of curse all this is just cosmetic... What is not cosmetic is correct neck angle and bridge height and placement on final instrument and I would correct Andrew that 99% of folks would not notice.
BUT!!!
For me it is part of the original design and intentional, not just mere coincidence.
I've posted it more than once so you can search for older threads, but will in simplified form repeat myself here.
The whole design is deeply rooted in art nouveau and motifs popular in the era. The whole body is not symmetric at all, even if you strip the points or scrolls, the basic shape suggests symmetry, but actually the scrolls and points cover the asymmetries and create feeling of greater symmetry. If you look at the curve between the points is mostly symmetric and forms kind of "reflex bow" curve that is perfectly symmetric or very close on origilnals, but modern makers rarely have that symmetry as that symmetric doesn't mirror well to the bass side of instrument (and if you adjust the bass side there appears a distinct bulge of curvature). The small bend at the end of one point just braks that symmetry of the curve and is kinda like spice in food. These details make the whole design make you think both about symmetry and asymmetry all at once, everywhere. The folks who don't bend the point creat eintentional symmetry that is out of place in the whole, because they break the rules of the design.
IMO, "corrected" designs like Collings look boring, they just don't offer as much food for an eye. But they mostly corrected the designs to make it simplier for tooling and fixturing.
Back to the neck...
For those curves to work properly the scroll should be placed close to neck so it won't stick out like sore thumb. logical is the size of the scroll cutout to follow the fingerboard edge. With this position of fingerboard you would need to move the apex of the "symmetric" body shape so much to the left that there would not be enough space for the smooth curved transition (unless you reduce the radius at the neck joint like some modern builders or something similar, and it shows) but the shape of that curve follows the "cutaway" to form nice balanced S shape so you if you change the radius under neck the whole balance goes out of window and that forces you to change more and more of the curves if you don't want make it collection of arbitrary curves.
So without changing the body curvature too much you can just move the fingerboard to the left on the neck blank but fix the neck on apex of the body curve (on centerline) and also place the dovetail on body centerline so the back button of neck heel is well centered when viewed from back. The argument about the fingerboard support not being symmetrical is good, but the design was based on F-4 that had crosspiece only on treble side and on scroll side the earlier models had no binding on the edge that followed into fretboard so there was no apparent "ear". On F-5 the ears are more apparent and asymmetric but that goes with the idea I posted above, the plastic crosspiece is nearly identical length on both sides of fingerboard but the curvature is not symmetric between bass and treble - again the same idea.
When I started building, all I had was basic dimensions of body (width length scale) and few pictures and few VHS tapes of good older bands. I drew my own drawings by hand and (being a mathematician) tried to draw it symmetric and prefect curvatures etc. I managed to get the body shape that had all those perfectionist attributes done and looked quite convincing but still I felt there's something different in those old originals in hands of BM and others (I had noticed that Hoss is not as nicely shaped). I even traced still pictures from TV screen (remember curved screens?) to find out but it took me almost decade to get it once the internet spread and I could analyze thousands of pictures of mandolins by almost every maker that appeared on internet using computer, not just lead pencil and semi-transparent drafting paper.

[Timbofood]

Adrian, I would so much enjoy an evening with you and Bill Halsey! The very concept of the “F-5” is about shape and form. Why the shape of the Florida, what about the visual balance to the scroll? The possibilities boggle the mind!
I have no dog in any of this fight about design but, I’d really enjoy an evening with anyone that has a bottle of wine and appetite! Heaven knows I’ve “after dinner drink conversation” through hour upon hour with a bunch of folks who have a greater knowledge than I.
I tip my hat to both camps but, I tend to lean toward the “accuracy to design” camp from the aesthetic. The difference is very subtle but, cannot be dismissed, it’s there!
There is something to be said for a real pencil and paper to make you “See” design. Shape, aesthetic is visual not always “symmetrical” balance can be achieved visually by an accentuation of an opposing element. Look at the aesthetically pleasing asymmetric designs of Lyon and Healy designs, they are visually stunning but maintain an element of aesthetic balance.
More recently, Steve Sorensen’s two point designs, beautiful but, far from symmetrical. They still behold visual/artistic balance.
The proof of the pudding is not, in the pudding but, in the eating. Which is to say the enjoyment.

[belbein]

To answer the OP's question directly and simplify what Adrian said a bit: The only two bits of geometry that's important is (1) that the plane of the strings and the plane of the fretboard converge at a relatively small angle that gives you reasonable "action," and (2) the center line of the nut lines up with the centerline of the bridge lines up with the centerline of the tailpiece. That's it. Everything else can be completely whacked. (I specifically said geometry, because there are building elements that are critical: like tuning the top and back, but that wasn't your question.)

If you'll notice, Simonoff--I think in some of his videos--says that you try to lay all of this out before you cut the neck joint and attach the neck, because variations there affect where the tailpiece will be. You don't put the tailpiece on until the neck is in place. Because that nut-bridge-tailpiece line can vary some distance if theneck joint is off a bit. Even if it varies an inch this way or that, there's no big deal as long as the strings and fretboard are fixed in relation to each other.

This is my understanding, anyway. Subject to correction by the pros here who actually know what they're talking about.

[amowry]

I deleted this post— I feared it might raise hackles rather than furthering the conversation.

[putnamm]

You don't put the tailpiece on until the neck is in place. Because that nut-bridge-tailpiece line can vary some distance if theneck joint is off a bit. Even if it varies an inch this way or that, there's no big deal as long as the strings and fretboard are fixed in relation to each other.

I think this is the only reason my one and only mandolin actually plays, because I put the tailpiece on at the very end. Don't remember why but I assume it is because Siminoff's book says so. Or maybe it was just dumb luck!

Thanks to everyone for talking me down. I was worried I would have to start back at the beginning!

[belbein]

Hey, Mr. Mowry … it ain't like we all have a lot else to do other that to get our hackles raised. I say: Raise away.

[Timbofood]

Hey, Mr. Mowry … it ain't like we all have a lot else to do other that to get our hackles raised. I say: Raise away.

Wait, I have a grilling site that I spend almost as much time with as I do here so, I can’t divide too much more time throwing sand in a whole new jar of Vaseline!
I can manage to monopolize corners on these two sites. Bad jokes take a lot of crafting. Well, maybe not a lot.
Be safe everyone.
Time to figure out what to do for a while. I like making music with other people, solo mandolin, doesn’t trip my trigger much.

[j. condino]

I deleted this post— I feared it might raise hackles rather than furthering the conversation.

Andrew, you are one of the least confrontational people I know!

[amowry]

Okay, here's what I was going to say-- it's not actually confrontational, I'm just always wary of saying anything that could be possibly be construed as "harshing" on Loars. I don't mean it as a criticism at all, just an expression of my personal preference, and I've always enjoyed seeing the little tweaks that modern builders have done to the original design.

My eye is always drawn immediately to that 15th-fret cross-piece, and while Adrian makes a great point about the origin of the offset neck on the F4, before the crosspiece was there, I've just always preferred the centered neck look that most modern builders (Gilchrist, Dudenbostel, Heiden, Ellis, Brentrup, etc.) use, which is why I decided on that look with my own F5s. As an example, Ellis (from their FB page) vs. Loar (from Carter Vintage):

[belbein]

You guys are no fun. If there's no fight here, I'll have to go back to work.

[amowry]

If you want confrontation, you should see me on the banjo forums...

Another consideration as a builder is that when a client asks for a neck with a 1 1/4" nut, you quickly run out of space next to the scroll if the neck is already offset.

[putnamm]

Since I've only ever built the one mandolin, and my approach to the next joint now will be different (dovetail instead of V) I pulled out my top template along with a neck blank and lined them up as best I could to get a feel for this. Since the top template is plexiglass it's kind of hard to see, but the centerline is etched in there. It looks like things will line up pretty well. The gap between the scroll and the bass side of the neck is pretty much even with the gap in the scroll all the way around until it comes to a point. So I feel better now about this situation.

[Will Kimble]

Just wanted to add if you are using a Loar-copy full sized pickguard with bracket then you need to offset the neck or it will hang over the edge of the body. Not that I have ever done that, lol.

[putnamm]

Just wanted to add if you are using a Loar-copy full sized pickguard with bracket then you need to offset the neck or it will hang over the edge of the body. Not that I have ever done that, lol.

I am an absolute amateur (both builder and player), but I have always viewed the pickguards as almost entirely decorative... It just seems like they'd get in the way.

[Will Kimble]

Well Loars had big pickguards and offset necks. Guess it depends what you’re trying to do. As far as pickguards getting in the way - they absolutely get in the way of fingernails that dent and scratch the thin & soft varnish finish that I use. All of my mandolins get them, take it off if you want. Haven’t done a full size pickguard with a bracket in a LONG time, though. I like the offset neck because that is how the old ones look to me. But I am ok either way. In general it seems the demand for Loar copy details are loosening up and I think that is a good thing.

[Will Kimble]

Made me think of a funny pickguard story - I told the guys at Collings they were gonna need pickguards for their varnish mandolins. Steve McCreary said “Bill really doesn’t like pickguards, I think we will be ok.” After the NAMM show (or whatever big event was next) Steve got ahold of me “You were right, we didn’t have pickguards and all the varnish mandolins got tore up. Please send pics of how you attach your pickguards.” So I sent him some pics, think he said my approach was a little “agricultural” but it gave them a place to start... lol

[Richard500]

Isn’t the F a decorative, rather than functional pattern? One that clearly is attractive to many. The pickguard, functional or not, changes the look, as does choice of finishes, etc. The utility of this piece likely is related to musical genre and the use as a strummed machine. Same with guitars. None of my antiques have a floating guard, and no gouges from picks. They likely never endured rock or even country. Sheltered lives.

[fscotte]

This whole discussion is why I only build A models.

[putnamm]

This whole discussion is why I only build A models.

Lol. As an absolute neophyte, all I knew was that I liked the sound of the mandolin. I wanted to learn to play, so I decided to also learn to build. At that absolute infantile stage I thought F5s just WERE mandolins. I didn't know there was any other kind! It's what I saw everyone playing. Only when I started studying building did I learn about the other designs.

[HoGo]

Now that I had a brief look at Gilchrist's web, I belive he redesigned a bit and uses off center neck as well. There were few noticeable changes of his work during the years but for the most current batches he changed few things.
Back to OP, actually the dovetail is not offet on body or neck... It's the upper fingerboard surface of neck that is shifted. The bottom of heel is on center... Just imagine preparing a bit wider neck blank and fit it centered but shift the fingerboard to the left edge instead centered and trim the treble side of neck blank to match edge of the board. I believe this is how folks at Gibson did it, they fitted still slightly wider neck blanks to rims and after that they marked exact position of the board and also nut edge on the blank for next steps on neck.