# Instruments and Equipment > Builders and Repair >  Gibson Mandolin Construction Details-Old, Loar era or before

## Darryl Wolfe

I have started several threads over the past ten years that fall into to this subject.  I decided not to search and just start a new one here in the builder section instead of vintage intruments.  We need to post and discuss some of the things we all see when dealing with repair of old Gibsons and maybe can it all together here

Hopefully we can make this thread as successful as some of the others I have started

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## Darryl Wolfe

I will start with..I have a pretty nice collection of Loar era A models and I have an unquestioned knowledge of Loar F5's

Upon inspection of my A models, I notice that (like most Loars) the fingerboard binding is the most likely part to NOT match the rest of the instrument.

In this case, a very simple fact that the fingerboards were made earlier...I will get to my point

Additionally, all of my A models show evidence that the soundhole binding was installed either before or right after the top was carved.  My point is that the soundhole binding tends not to match the body and is more appropriate to the fingerboard

I sit here typing this looking at 5 examples of what I am laying out here for discussion

In each and every case I am looking at fingerboard and soundhole binding that precedes the body binding by a year or so

I really do not think there is a connection between the fingerboard and the soundhole other than the possibility they were done way earlier, and maybe fingerboards are like "parts"

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## Darryl Wolfe

Next...If you look carefully at how the concave area is carved on each side of the fingerboard at the neck...they had a tool.

I have two mandolins that display evidence that they had a flat sided tool that gauged off the fingerboard side and top surface to create the scooped concave area at the neck.  I believe proof lies in the fact that several fingerboard/neck join surfaces have vertical wood that extends down until the curve starts.  Also, you can take a gauge and see it.  I will post some pictures of that.  But in essence, some of my examples are perfect, but others went "low" and have vertical wood that is stained/painted over to keep the bottom edge of the fingerboard binding straight and level

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## Eric Hanson

I look forward to this thread very much. It will be very interesting to see first hand, from the viewpoint of a repairman, what is seen in the original building process. 
 Especially with the number of highly talented repair people who frequent this site. Ones who have worked on a number of the Loars and other instruments made by Gibson over the years. 
 I have to do something similar when tracing out electrical circuits and trying to find why one does not work. The puzzle is always rewarding when you solve it. 
 Pictures please, pictures Darryl. :-)

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## Michael Lewis

Yeah, Darryl, pictures please.  I'm having a bit of difficulty matching your description with the shapes of the parts as I see them in my mind.

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## Spruce

> ....and I have an unquestioned knowledge of Loar F5's


I've got a whole folder here filled with your Loar musings...
Incredibly insightful information about a weird, weird instrument....




> Next...If you look carefully at how the concave area is carved on each side of the fingerboard at the neck...they had a tool.


How about 2 tools, one for each side?
They _are_ quite different from one another....
Even on the "symmetrical" A5....   :Wink:

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## Michael Lewis

Now I think I am picturing it correctly, the scooped surfaces that the cross piece divides, right?  Those have been one aspect of "completed surfaces" that lead to top grade workmanship.  Not the fact they are there but the fact they are done so well and the surfaces are completely smooth  and the edges are crisp.   I find the design a bit fiddly but nice when well executed.

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## Darryl Wolfe

> Now I think I am picturing it correctly, the scooped surfaces that the cross piece divides, right?  Those have been one aspect of "completed surfaces" that lead to top grade workmanship.  Not the fact they are there but the fact they are done so well and the surfaces are completely smooth  and the edges are crisp.   I find the design a bit fiddly but nice when well executed.


Correct.  I have several examples where the top is cut lower than the fingerboard surface, indicating they had a tool (or tools..Spruce) to do this with.  I have not had a chance to get some pics together, but we will get this thread rolling along

No, I may not have made it so clear, but I expect all to add stuff along the way

d

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## Chris Oliver

> Correct.  I have several examples where the top is cut lower than the fingerboard surface, indicating they had a tool (or tools..Spruce) to do this with.  I have not had a chance to get some pics together, but we will get this thread rolling along


Darrel, I have often thought of making a small jig to shape that area with consistent results. When you start collecting photos, please do include a pdf of the profile of both sides.
thanks.

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## sunburst

I just examined an A Jr., paying particular attention to those "flutes" because of this thread. Because of the neck angle, or something(?) there is a little bit of vertical wood on the drivers side, but only near the neck joint. It tapers out before the end of the fingerboard. If they set the tool(s) to cut to the desired binding level at the edges of the top, that could account for the occasional bits of vertical top/riser wood under the fingerboard. It's not something I've looked for in the past, but I'll proibably always notice what that place looks like from now on!

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## Darryl Wolfe

Here are some pics

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## Darryl Wolfe

Next detail.  Gibson appears to have profiled the outside edge of the neck joint to finished spec prior to shaping the neck.  Occasionally I see evidence of rasping that area.  This is the same A4.  But, on Loar F5's I often see this flatness and some filler between the neck and body that hides under the dark sunburst.  On a mahogany neck like this you can get some grain tear, on the maple F5's it is usually more finished looking

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## Steve Sorensen

Love how this thread is starting.  More pictures for the peanut gallery, please ! ! ! 
Steve

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## MikeEdgerton

Gibson was a factory, I would think they would have different people making the different parts of the instrument and I could see where the guy doing necks could be way out ahead of the people doing the final assembly of the bodies. When you look at the Gibson second line instruments most of them appear to amalgamations of whatever parts they had laying around the factory at the time.

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## Spruce

> ...indicating they had a tool....


Can we speculate as to what that tool (tools?) might have looked like??

A plane that ran on the pre-freted fingerboard?
Or, they might have shaped those buttons before the f'board went on?
_Very_ interesting....

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## Darryl Wolfe

> Can we speculate as to what that tool (tools?) might have looked like??
> 
> A plane that ran on the pre-freted fingerboard?
> Or, they might have shaped those buttons before the f'board went on?
> _Very_ interesting....


My mind sees something riding the fingerboard.  However, the scroll side of an F5 presents a new set of problems....maybe, hence the weirdness there

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## Darryl Wolfe

The little wooptidozion on the binding kinda supports this

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## Spruce

> The little wooptidozion on the binding kinda supports this


Wooptidozion for sure...   :Wink: 
So the 'board was on...
Maybe a cove bit setup that ran an on a 2mm rail flush to the binding?

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## testore

That makes me feel better...I've done that.

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## Darryl Wolfe

I knew Spruce would take a liking to that word

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## SHORTY

Darryl,
          Just send all the Loars to my place for further inspection. Of course theres no need for a return shipment plan.
   Envy, envy on my part.
      Thanks for the photos, that will help me in the way I plan ahead on my next build.
            Shorty
   "Tunnel Rat At Large'

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## Glassweb

Speaking of Loar specs... anyone out there have the fret slot spacing for Loar era F5s? I have found that modern, "tempered" F5 boards often produce a mandolin that will not play in tune... particularly in the first position and when playing open string chords. Were Loar F5 boards fretted with a spacing that is a different tempering than today's fingerboards? Thanks!

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## Bernie Daniel

Wooptidozion = the little wood ledge? (for the non-builders)

On second thought I guess this is like whoop-tee-doo with a zzz-en attached?

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## billkilpatrick

in all the bumph i've read concerning the "the loar LM-600" i've never seen anything to suggest it's genuinely - verifiably - connected to lloyd loar's original specification - or is this just assumed to be the case.  if so, i'd be interested to see how it - the LM-600 - matches up with an original, lloyd loar signature model.  in the "wooptidozion" (great word! - you've invented something!) close up photo, for example, it appears there's more space around the scroll than with my LM-600 but on closer examination i'd guess they're pretty much the same.

great thread - very interested to read/see more.  thank you.

... later - dove a little deeper into the "the loar's" site and found this: "The Loar’s outstanding new all-solid mandolin is an accurate replica of the original 1920’s F5-style model."  question is, how accurate and how does handicraft from 1920's america compare with same from modern china?

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## sunburst

> Were Loar F5 boards fretted with a spacing that is a different tempering than today's fingerboards? Thanks!


Loar, and other contemporary Gibson mandolins, often had fret slots that were not very accurately spaced. Some say that they were intentionally cut for "better" intonation, but best I can tell, they were simply 'off' a little. Modern makers usually use fret spacing accurately measured for equal temperament, and 'boards have generally improved since I've been building (not very long, in the grand scheme of things). 'Boards I could buy were all different some years back, and that's the reason I started making my own (if they were all different, how could they all be right?). Now, with a new crop of luthiers with high levels of attention to detail, with CNC and other accurate methods of cutting frets, there's no excuse for a vendor selling fingerboards that do not have accurately cut fret slots, so accuracy of fret positioning is pretty close to universal.

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## MikeEdgerton

I seem to recall a story about a machine Gibson had for cutting fret slots with shims that were worn or wrong.

This isn't the one I was looking for but it discusses the issue.

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## Paul Hostetter

Rick Turner and I have both seen that slotting machine at Parsons Street.

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## Paul Hostetter

> in all the bumph i've read concerning the "the loar LM-600" i've never seen anything to suggest it's genuinely - verifiably - connected to lloyd loar's original specification - or is this just assumed to be the case.  if so, i'd be interested to see how it - the LM-600 - matches up with an original, lloyd loar signature model.


Having been in the thick of it with helping develop the "The Loar" mandolins, I can tell you not to bother comparing. Some effort was spent dialing in some details which involved referring to real Loar F-5s, but there are limits to what can expect from a shop crew that trained as violinmakers who are really just trying to work from plans or other copies. Especially in that price point. 

For fun, here's an early 600 prototype from several years back side by side with the Rill Thang. The current 600 and 700 mandolins are closer now, but, um, not a dead match. 



The one on the right did not look like the one on the left when it was new!  :Wink: 

.

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## Glassweb

> Loar, and other contemporary Gibson mandolins, often had fret slots that were not very accurately spaced. Some say that they were intentionally cut for "better" intonation, but best I can tell, they were simply 'off' a little. Modern makers usually use fret spacing accurately measured for equal temperament, and 'boards have generally improved since I've been building (not very long, in the grand scheme of things). 'Boards I could buy were all different some years back, and that's the reason I started making my own (if they were all different, how could they all be right?). Now, with a new crop of luthiers with high levels of attention to detail, with CNC and other accurate methods of cutting frets, there's no excuse for a vendor selling fingerboards that do not have accurately cut fret slots, so accuracy of fret positioning is pretty close to universal.


Thanks John... understood. But I'm still wondering if Simonoff or anyone out there knows if the "Loar scale" exists and, if it does, in some way achieved even better intonation than the current, tempered fretboard. I have played a number of Gibson mandolins that were out of tune as well, including the later, block-inlayed F5s, but all the Loars I've played seemed to play pretty well in tune... especially in the 1st-3rd position and with open chords.

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## Paul Hostetter

I think the anomalies of Gibson boards have been discussed plenty in other threads, and the gist is: their slotting machine changed every time they took it apart to sharpen the blades. And they weren't alone—I have a collection of Martin guitar boards that are disturbingly at odds with one another. It's a wonder that anyone ever got in tune. 

I'm more interested in getting back what Darryl set out to do, which is deconstruct the shop methods used in the days of yore.

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## Glassweb

fair enuff Paul... thanks for the info...

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## Jim Hilburn

During the time I spent with Steve Gilchrist in Santa Cruz we discussed the way Loars were made. Steve pointed out that the backs were attached first and the glue cleaned up. But once the top went on they were hung to dry at apparently a bit of an angle and they all have glue squeeze that runs the same way on all the instruments.

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## David Collins

There's nothing about spacing on old Gibson mandolins worthy of being considered beneficial or as an improvement over standard spacing. I've studied their fret spacing a great deal, and have yet to be able to firmly nail down exactly what formula or system they used, but it's pretty much just an academic curiosity and not a model I feel worthy of imitation. They are really more crude primitive formulas, done out of lack of knowledge rather than noble goals or intentions, and they never happened to accidentally stumbled upon anything great either. And there is no fret spacing pattern particular to the Loar instruments - the same pattern (with slight variations in errors) existed before he came and after he left.

 Of all the other things old Gibson mandolins have earned the worthy position as benchmark, fret spacing is not among them. In any case, that's probably quite a different discussion from here. The tooling was a simple gang saw, no surprises or mysteries there.

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## Bernie Daniel

Regarding Paul's point yes the topic DOES seem to  have strayed a lot from the OP.  In several ways I would say as Darryl seemed more interested in the building of Loar-era A-models and not Loar-signed 5-series instruments per se?  Not sure about that.  

With that thought in mind wasn't the entire effort by Derrington to recreate the Gibson F-5 a pains taking, no detail overlooked search for the road map as to how Gibson constructed those LL-signed mandolins?  

So that's what makes me think the focus here was intended to be on A-model building.  Just suggesting.

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## Skip Kelley

"The one on the right did not look like the one on the left when it was new!"

 :Laughing:  Thats great!

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## Gail Hester

> Steve pointed out that the backs were attached first and the glue cleaned up.


I have to disagree Jim.  I never saw them assemble one (wish I had a time machine) but the top and neck had to go on first to tap tune the way Loar specified.  I think Roger would confirm this.

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## Jim Hilburn

Just passing on what Steve said and I think he's seen the inside of more Loars than the average guy. 
As far as Derrington painstakingly re-creating the Loar, I don't see how you do CNC peghead binding and call it an accurate re-creation. They were off on a lot of details. If you want to see an accurate replica go see Bill Halsey.

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## hank

Glassweb on the subject of intonation I'll start another thread on shortening the fretboard 1/32" at the nut end with a compensated nut at the A course adding it back.

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## billkilpatrick

> ... The one on the right did not look like the one on the left when it was new!


thanks paul - had no idea you were involved in the making of this wonderful instrument - well done, grazie-grazie-grazie ... mille!  side by side, taking wear and tear and passing time into account, they don't look all the different - but of course, it's all in the detail;  "the gibson" and "the loar" might share the same association the new vw and the old beetle have.

don't know where gibson recruited its instrument makers in the early days (did they refer to themselves as "luthiers?") but i would guess a fair amount of them could have been violin makers.  nitrocellulose lacquer aside, if similar tools and materials were used in constructing both, should we expect radical differences between the new loar and the old?

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## jim simpson

Paul,
Thanks for posting the Loar next to the Gibson Loar. It looks like the Loar's scroll is similar to so many early efforts where the inside of the scroll just doesn't make it far enough. It always seems to be the first thing I look at on an F model.

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## hank

Another common difference is the little wave on the peghead opposite the scroll has different amounts of curl from builder to builder.

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## Paul Hostetter

The scroll on the more recent ones is far betterthat was one of the first they built. 

Maybe it's time we get back to Darryl's original thread?

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## billkilpatrick

wasn't my intention to hijack the thread - i'm very interested in the original gibson details and would love to see and hear more about how they were made.   the only reason i mentioned "the loar" was for purposes of comparison. (grovelgrovelgrovel ...)

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## Mike Black

> Next...If you look carefully at how the concave area is carved on each side of the fingerboard at the neck...they had a tool.
> 
>   But in essence, some of my examples are perfect, but others went "low" and have vertical wood that is stained/painted over to keep the bottom edge of the fingerboard binding straight and level


Darryl,  Are the examples you have that go "low" have a fingerboard that is thinner than normal?  That might add more fodder for the use of some sort of tool that just went lower on thinner fingerboard. 

 I've been racking my brain thinking of what kind of tool could have done this.  Thanks for the brain teasers!

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## dan in va

Interesting observation about the inside glue running in the same direction on the Loars.  Maybe we don't really know much about the Loar era manufacturing process and tap tuning....maybe they did it and maybe not so much.  Siminoff talks about needing a quieter environment than a factory to tap tune properly (enter the deflection method), and maybe there wasn't much in the way of acoustic tile back then.

Maybe the craftsmen did what some of the old violin masters did by finishing the graduation after stringing them up.  This could account for Gilchrist's notion about the glue.

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## woodwizard

Here's a view of mine.
(A4)

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## Mike Black

> I believe proof lies in the fact that several fingerboard/neck join surfaces have vertical wood that extends down until the curve starts.  Also, you can take a gauge and see it.  I will post some pictures of that.  But in essence, some of my examples are perfect, but others went "low" and have vertical wood that is stained/painted over to keep the bottom edge of the fingerboard binding straight and level


Darryl,  Another question...  Do you think that could be a shim under the fingerboard?  Or is it part of the top?  In the third picture (of post #11) it looks like it's a shim that is sitting on the rosette.  Unless the rosette stops at the fingerboard instead of how they normally continue under the fingerboard.

That's the way that Woodwizard's (Mike Parks) mandolin looks like too.  But just the part at the end of the fingerboard.

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## Darryl Wolfe

> Darryl,  Another question...  Do you think that could be a shim under the fingerboard?  Or is it part of the top?  In the third picture (of post #11) it looks like it's a shim that is sitting on the rosette.  Unless the rosette stops at the fingerboard instead of how they normally continue under the fingerboard.
> 
> That's the way that Woodwizard's (Mike Parks) mandolin looks like too.  But just the part at the end of the fingerboard.


No shim.

I do not think anyone has "hijacked" this thread.  As long as we are taling about how Gibsons were constructed and any reference to how some other mandolin is constructed differently is still headed in the same direction

Which plate was put on last.  Let's discuss that.  I think the back went on last.  Many builders do otherwise to hide messy inside glue joint from the last plate.

I personally think Gibson performed some profiling of the rim/top/neck assembly while the back was off

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## Darryl Wolfe

This catalog cut offers no proof, but with the riser block intact and the dovetail cut, I would think the top goes on next.  I have always believed that the cross piece/riser block was their zero reference point for the entire construction

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## billkilpatrick

thanks - i bruise easily ...

when "mid-missouri" was still alive and well, i remember mike dulak complaining about how he and someone who worked for him had differing views on neck measurements.  is there a similar disparity in your collection?

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## Jim Hilburn

The only messy glue joint that's visible through either the oval or F hole would be the back joint. If the back went on first it would be easy to clean any glue mess but if it was the last plate glued on it would be very difficult to clean it. 
Darryl, don't you have an old Gibson or two you could inspect and get back to us?
I tried to find pictures of Monroe's Loar during the repair that might show some evidence but didn't find anything.

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## Mike Black

> This catalog cut offers no proof, but with the riser block intact and the dovetail cut, I would think the top goes on next.  I have always believed that the cross piece/riser block was their zero reference point for the entire construction


The Catalog that Darryl posted shows the top as if a pattern carver did it.  That might explain the lip under the fingerboard.  Maybe the pattern carver went a little low in that area.

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## Mark Seale

> This catalog cut offers no proof, but with the riser block intact and the dovetail cut, I would think the top goes on next.  I have always believed that the cross piece/riser block was their zero reference point for the entire construction


From the finished rim and riser, you can fit the neck and glue on the back and clean up any glue that would have been visible through the f holes.  Gilchrist was pretty confident in the order in which the mandolins were put together.

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## Darryl Wolfe

> The only messy glue joint that's visible through either the oval or F hole would be the back joint. If the back went on first it would be easy to clean any glue mess but if it was the last plate glued on it would be very difficult to clean it. 
> Darryl, don't you have an old Gibson or two you could inspect and get back to us?
> I tried to find pictures of Monroe's Loar during the repair that might show some evidence but didn't find anything.


will do

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## Gail Hester

> The only messy glue joint that's visible through either the oval or F hole would be the back joint. If the back went on first it would be easy to clean any glue mess but if it was the last plate glued on it would be very difficult to clean it.


Using hide glue does not have to be messy.  It's not a given that if you can't see squeeze out inside then the back was installed first.

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## Jim Hilburn

But if there is glue run on the top but not the back it would support the back going on first theory and that's what Steve says he has seen.
I don't have a point to prove here, I just thought I'd bring it up since it seemed to fit the topic and I have no experience with old Gibsons myself.

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## Darryl Wolfe

I think I have enough of 'em to figure this out  :-)

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## Gail Hester

I don't have a point to prove either Jim, just discussing.  The only reason I brought it up is that the point is an important one for the following reason.  If the backs went on first, Loar mandolins were not tap tuned.  That is an important issue because there is so much evidence that they were tap tuned as an assembly and that the tones bars were refined during that process.  Whether we as luthiers believe tap tuning has value or not is not the issue but it is historically important in terms of Loar F5s to know if the notion of tap tuning is fact or urban legend.

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## Mark Seale

> I don't have a point to prove either Jim, just discussing.  The only reason I brought it up is that the point is an important one for the following reason.  If the backs went on first, Loar mandolins were not tap tuned.  That is an important issue because there is so much evidence that they were tap tuned as an assembly and that the tones bars were refined during that process.  Whether we as luthiers believe tap tuning has value or not is not the issue but it is historically important in terms of Loar F5s to know if the notion of tap tuning is fact or urban legend.


Tap tuning as an assembly would describe an instrument in the white and probably alludes to tuning the f holes.  I don't see where tap tuning with the back off would be vastly different than tap tuning just the free plate top and tone bars and then tuning the chamber after assembly.  But that is the opinion of someone with VERY little personal experience and some time listening to the gospel according to Gilchrist.

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## HoGo

Oh, I missed my favorite topic.... I hope it's not too late to add something.
Back to the beginning of this thread. I don't think there was a machine used to shape the ramps at the f/b end. The one example looks like screwed one at the factory and fixed with filler (wood strip?) Perhaps the strip was added with f/b replacement (which was their way of re-fretting), perhaps the neck projection was too low (owner wanted to change to adjustable bridge?) and strip was added atthe same time and finish was just touched up (or painted up). Otherwise the ramps are easily trimmed with gouge of proper diameter.
The pics of neck heels look EXACTLY like my mandolins (this is first time I noticed it on Loars and never intended to copy this).
I fit the neck slightly oversized and do the final trimming either right before gluing (I just undercut at the angle the very edge of neck that touches sides to see if the fit is good) or entirely trim the area after gluing. I use 5mm chisel to cut right to the ribs and cut at slight angle so I don't tear grain off the neck and then use scraper. I pull scraper from the joint line towards headstock and if I don't use sanding sticks or extra care I end up with the effect as seen on the pics. The f/b binding anomaly matches as well.
Now to the assembly. I agree that they likely made a lot of parts at once and then used them up over time (just look at the pics from the smaller chinese workshops with hundreds of tops hanging on one long line like clothes).
I firmly believe that backs were glued first. Actually I don't doubt at all. I'm attaching one of several pics that Bill Halsey sent me. He took pics of all his ovals (six or so) and they are pretty much all same (this one is Loar era) - NO glue on backs, but visible squeeze-out on tops (sometimes more than in this pic).
I'd say assembly went like this: 
1. rims glued
2. neck riser blocks added
3. dovetail cut (routed?)
4. backs glued and inside cleaned
5. tops glued
6. necks fitted very oversized (dovetail and trussrod was on centerline of neck blank now) and perhaps slightly reduced after fitting to body and f/b traced in its future locatrion
7. fingerboards positioned offcenter and glued (no pins were used, so some margin on neck surface was needed)
8. headstock overlays glued (OK, this is speculation, but it is much easier to fit overlay, with pins, to end of fingerboard than pinless f/b to already glued and bound ovelay),
9. shape of headstock finalized.

Gibson used pins in several places and I often wondered why not in fingerboard... Perhaps they used pins/thin nails during gluing f/b but they were driven into oversized neck besides the fingerboard and went away after assembly. This would make the headstock shaping easier.

Regarding the tuning of the F-5. The catalogs tell what was done. Free tops and backs were struck with hammer and bowed to detemine their pitch and then the assembled instrument was strung up in the white and tuned again. This was common procedure of (even top) violinmakers of the day. The CT shows that there was significant amount of wood removed from outside of the top after assembly (the area at the bass side of the f/b extension shows it best) (this picalso shows a drop of HHG at the lining, bright color).
My take is that the first (or first few) prototypes were made and tested and the specs of the best one were used for the rest. First the parts were carved to specs (the known specs sheets) and perhaps they made attempts during making to tune the parts to pitch from that succesful instrument. But with wood of similar origin and good specs to start with there was not much needed to stay within family sound (the new Northfield mandolins come to mind, never played one, but they seem to be getting somewhere... perhaps closer to Loar than Gibson MM, don't throw stones at me, this is just MY opinion)

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## HoGo

> Speaking of Loar specs... anyone out there have the fret slot spacing for Loar era F5s? I have found that modern, "tempered" F5 boards often produce a mandolin that will not play in tune... particularly in the first position and when playing open string chords. Were Loar F5 boards fretted with a spacing that is a different tempering than today's fingerboards? Thanks!


I've seen one nice conversation on this topic on one of the b@njo sites (I promise I didn't go there intentionally, goole took me there :-)). Someone discussed old Gibson banjo fingerboards and how they were off. One guy posted a graph with measurements off four or five different Gibson fingerboards (one was tenor guitar, some RBs, some TBs), he measured differences from perfect tempered fingerboard and the result was interesting... ALL the data rows created very similar curves. He lined up the nut with perfect board and so the zero fret had zero differnce from ideal, from there they all went to positive numbers then down to negative at fret #5 or so and down deepest at 8,9 and back close to zero at 12th and up to positive numbers. This indicates that they used an imperfect math formula (or too much rounding) to calculate the frets in the first place. The temperde tuning was well known back then, but with no calculators I guess some old schemes based on ratios were used to aproximate the distances.

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## Gail Hester

Thanks Adrian for entering into the discussion.  I am trying to keep an open mind and get to the facts and data and ultimately a little knowledge like everyone else.  I would appreciate your catalogue reference for tapping free plates as I have never read that before.

Here is a picture of FL5 taken by Roger in the Gibson factory Kalamazoo circa early 70s.  He said that one of the gentlemen working on F5s had been there for over thirty years and claimed that this assembly order was per the original specifications and had not changed since the twenties. :Coffee:

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## HoGo

> Thanks Adrian for entering into the discussion.  I am trying to get to the facts and data and ultimately knowledge like everyone else.  I would appreciate your catalogue reference for tapping free plates as I have never read that before.


It's right there in the "Master Model brochure" that came with each F-5. I found the scan.... My interpretation was from memory, but I believe was not too much off. The rest can be seen in the measurements and CT scans from actual instruments.
There is even more in those few brochures and cactalogs than people think. Sometimes you need to read between the lines. But many things are written there in clear words and perfectly fit thinking/working nature of the era.

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## HoGo

Just to add that I believe they didn't disassemble too many instruments. You can affect sound by removing material just as much from outside than from inside. And also the tuning of free plate is greatly changed after trimming the plate and cutting the scroll so after disassembly it would not give the same pitch as before.

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## Red Henry

The problem of "inaccurate" fret spacing on the old F-5s is an interesting one. David McLaughlin likes the way his original fretboard was slotted (that is, the intonation it gave) so much that when he replaced the fb a few years ago, he found an instrument worker who would reproduce the original fret-slot spacing to the nearest thousandth or so. 

Another interesting subject is the scale templates which Gibson used. In comparing original banjo, mandola, and mandolin scales several years ago, placing frets on different necks opposite each other, it looked to me as if Gibson may have used only two master fret scales, just starting and stopping at different portions of each scale for various instruments. I have forgotten the details now, but it was something like this: One master scale was the long 5-string scale, which corresponded to their 19-fret tenor scale, and another was the short 5-string scale, which corresponded to the 21-fret tenor scale. The scale on my H-2, and the regular 13.75" mandolin scale, each match one of these (I forget which ones, now). If anyone on this thread has some old Gibson banjo necks to compare with the necks of their mandolin collection, these rusty memories of mine can be re-checked or verified.

Then, of course, by the 1930s, the frets (especially on cheaper Gibson mandolins and tenor banjos) were placed in pretty sloppy places sometimes, I assume because the old templates were getting badly worn!

Red

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## Paul Hostetter

The archives have several earlier discussions of how Gibson managed this, the machine on which they were cut, and why the spacing wobbled. It wasn't about templates, it was about shims between parallel circular blades on an arbor.

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## Mark Seale

This picture just showed up in the Gil Jrs. thread.  Its fairly illustrative of the process that Gilchrist works with and believes the old Gibsons were done.

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## Mike Black

I was thinking the same thing when I saw that picture again today.

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## mtucker

another.

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## Bill Halsey

> The archives have several earlier discussions of how Gibson managed this, the machine on which they were cut, and why the spacing wobbled. It wasn't about templates, it was about shims between parallel circular blades on an arbor.


True, Paul.  Heritage Guitar still uses the same machine.

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## Austin Clark

Well, I can sure tell you this:  Gibson was not using a CNC router (like Gilchrist) to cut that channel on the tops.  :Laughing: 

Seriously though, does the remaining glue on the inside of the top mean that much?  It was a factory setting and maybe one of their ways of saving time was to just not clean the squeeze-out from the tops thinking it would not be seen and was therefore not necessary.  I am not convinced of the selling points of gluing on the back first. In my humble experience it doesn't seem to be the most efficient way of operating.  I do think that the evidence of neck shaping after gluing in lends the idea that the box was assembled before the neck was glued in and then subsequently shaped to fit the button.

If the back was left off while the dovetail was being fit, it stands to reason that the top was on at that point as the rimset has to be held stiff to keep the centerline in mind during the fitting process.  This suggests that the top went on before the back. (obviously, the back could be the thing that holds it stiff, but what a PITA to fit the dovetail when you can only see inside one end. I don't see a factory doing it this way)

I am suggesting then that the top was glued on, the dovetail cut and neck fit and THEN the back was glued on and then neck was glued in last and shaped to fit the button.

Is my logic ok here?

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## Jim Hilburn

A lot of photo's from Steve have been showing up here and this is the one I saved.
He says he sets his necks in his "master mold" and I believe this is what he's talking about. If he removed that center forming press he could set the neck although it looks like the front part of the form might interfere but it doesn't seem logical that he would move it to another jig. But that's how he sets the necks without having the top on.
 Once you glue the back on in that form then it should all line up. This doesn't prove what Gibson did but shows how they might have done it.

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## Jim Hilburn

As a follow-up, I looked more closely at the photo I posted and while it pixelates out a lot as you zoom I'm thinking the rim is elevated above the table on that jig which would allow for the neck set.

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## HoGo

Austin,
there's no visible glue around the back even inside the scroll but there are large drops pretty much everywhere around top.
Also, did you notice how Loar back button binding is done? The ledge is cut at an angle following curvature of neck and piece of binding was not cut from strip and bent but from larger sheet so it formed wide U letter and then bent. This piece was very probably added last as it is invariably mitered into the adjoining bindings even in sidebound mandolins. The neck should be pretty close to final shape near heel and held firmly in the body against the back for cutting the ledge.
BTW, I don't consider fitting compound dovetail with back attached all that hard, that's the only way I do it. All prewar Martin guitars necks were fitted after assembly. The only difference is few strokes of plane or sandpaper stick on the heel so it seats against the back snugly.
Gibson may have used similar tool to what Don Macrostie uses. Simple custom blades in a large shaper head . Nothing fancy. They had the power and much of their neck work was done on shapers and large machines.

Jim, I believe you are right about Gil, I remember old newspaper article someone posted here few years ago where in a pic was row of complete rims (with riser blocks) with necks fitted in their dovetails, no back or top in sight. BTW, Gibson uses (before the flood) dummy back, attached with dowels and rubber band, to keep the body from flexing while fitting necks.

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## Jim Hilburn

Yeah, Adrian, I think that was my photo. Through a weird coincident I ended up with an article from the Warnambool paper in 1981 with an piece called "Demand in US for Local Mandolins". It was the story of Steve only a few years after he began building and there's a picture of him playing one of his mandolins with "The Gibson" on the peghead and another of the row of rims with the rough cut necks dovetailed to them.

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## Mike Black

Do you still have that photo Jim?

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## Jim Hilburn

I guess I should have known you'd ask. Nearly 30 years old.

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## Austin Clark

Fascinating stuff -Thanks guys! This has been an interesting thread to follow.

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## Mark Seale

> Well, I can sure tell you this:  Gibson was not using a CNC router (like Gilchrist) to cut that channel on the tops. 
> 
> If the back was left off while the dovetail was being fit, it stands to reason that the top was on at that point as the rimset has to be held stiff to keep the centerline in mind during the fitting process.  This suggests that the top went on before the back. (obviously, the back could be the thing that holds it stiff, but what a PITA to fit the dovetail when you can only see inside one end. I don't see a factory doing it this way)
> 
> I am suggesting then that the top was glued on, the dovetail cut and neck fit and THEN the back was glued on and then neck was glued in last and shaped to fit the button.
> 
> Is my logic ok here?


The logic is sound, but even the mandolins themselves speak to the fact that the centerline was "loosely" followed.  That seems to be one of the intricacies/idiosyncrasies of the Loars.

Oh and which channel are you referring to that is cut on CNC?  Gilchrist uses a duplicarver type setup for tops and backs.

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