When is a fingerboard too thin to resurface?

[Don Noon]

Is there any rule-of-thumb for you pros to decide when a fingerboard is beyond resurfacing and needs to be replaced?  2 or 3 mm edge height or anything like that?

Presumably it would be different for a picky pro violinist vs. an amateur fiddler.  And how much they want to invest.

[Deo Lawson]

It's all dependent upon the thickness of the neck and the projection at the bridge. When the board starts getting thinner those few missing mm can cause problems.. cramped fingers, bow hitting the bouts. In some cases anyway.

Aesthetically speaking I don't think anyone pays attention to the board thickness, except nerds like us.

[Mark Norfleet]

The two criteria I usually mention are if a player feels like they have to close their hand too tightly, and if the FB flexes too much when playing on the unsupported part.  Sometimes I’ll replace one if the measured projection and or bow clearance is getting is getting too low for playability and a new FB will make a worthwhile difference.  I also will replace FBs if they’re on the thin side and I’m resetting the neck.

[deans]

Some players, esp those with multiple instruments (who might want them to feel similar) will want their fingerboard changed well before there is any technical or structural need to do so. 

On they other hand Ive run across some older guys, who have fingerboards barely thick enough to have the right scoop, adjusting over the years to an ever thinning fingerboard. Often violists.

I suppose many shops will replace a thin board when it looks like there might be not much adjustment room left. I can say for sure that I bought an old instrument once where I pointed out that the board will need changing before I'm done with it.

 

 

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[Don Noon]

My specific reason for asking this question is for deciding how much material to remove under the fingerboard in the neck zone, for the purpose of saving weight.

If you start with an edge height of 4.5mm, certainly taking off 4.5mm over the years for resurfacing does not seem reasonable, as edge height would go to zero (unless the radius flattens a lot).  And if the entire surface was reduced uniformly, the wide end would get paper-thin.

I'm guessing that planing off a total of 2mm is a pretty big amount, mostly in the 1st position area, and more than that would be likely the time to replace the board.  Opinions?  

[Jeffrey Holmes]

How much weight are you trying to save Don?  Would routing a channel in the center of the fingerboard's glue surface be enough (Degani and some other makers did this) or are you going for a whole lot more of a reduction?

[Mark Norfleet]

3 minutes ago, Jeffrey Holmes said:

How much weight are you trying to save Don?  Would routing a channel in the center of the fingerboard's glue surface be enough (Degani and some other makers did this) or are you going for a whole lot more of a reduction?

Or..., he could laminate ebony onto a spruce core as earlier makers did.
 

 

[Deo Lawson]

I would agree that if your goal is maximal weight reduction, a laminated board is your best option, or some modern composite material. Even if you shave the bottom right up to the absolute max it would still be heavier than a laminated spruce board.

[Jeffrey Holmes]

21 minutes ago, Mark Norfleet said:

Or..., he could laminate ebony onto a spruce core as earlier makers did.
 

Where is my "like" button.  :-)

[deans]

46 minutes ago, Jeffrey Holmes said:

Where is my "like" button.  :-)

Interesting, do you do a lot of laminate boards? Something you do for general use instruments or just for period equipment?

[Don Noon]

 

2 hours ago, Jeffrey Holmes said:

How much weight are you trying to save Don?  Would routing a channel in the center of the fingerboard's glue surface be enough (Degani and some other makers did this) or are you going for a whole lot more of a reduction?

1 hour ago, Deo Lawson said:

I would agree that if your goal is maximal weight reduction, a laminated board is your best option, or some modern composite material. Even if you shave the bottom right up to the absolute max it would still be heavier than a laminated spruce board.

My primary goal is to make instruments that are not obviously different from conventional high-quality modern ones, and within that constraint, have the best performance and lightest weight, while still being serviceable by folks like Jeffrey (and not having issues that need his servicing frequently).

For the lightweighting I'm currently doing, I save somewhere around 10 - 12 g on the fingerboard as modeled by my cat in the photo.  It's not a huge amount, but for 15 minutes of setup and runtime on the CNC, it seems worth doing.  There's still 3 mm minimum thickness above the pocket, to allow for some resurfacing.  For violas, its more weight saved and probably more important.

Do you get much resurfacing potential with a laminated ebony/spruce fingerboard??

 

[Jeffrey Holmes]

2 hours ago, deans said:

Interesting, do you do a lot of laminate boards? Something you do for general use instruments or just for period equipment?

I just liked Mark's idea...

[Jeffrey Holmes]

5 hours ago, Don Noon said:

 

My primary goal is to make instruments that are not obviously different from conventional high-quality modern ones, and within that constraint, have the best performance and lightest weight, while still being serviceable by folks like Jeffrey (and not having issues that need his servicing frequently).

For the lightweighting I'm currently doing, I save somewhere around 10 - 12 g on the fingerboard as modeled by my cat in the photo.  It's not a huge amount, but for 15 minutes of setup and runtime on the CNC, it seems worth doing.  There's still 3 mm minimum thickness above the pocket, to allow for some resurfacing.  For violas, its more weight saved and probably more important.

 

Looks like the similar idea to what is employed on one model of the Corene composite boards to reduce weight. A little wider though.

The Deganis ran the (rounded) channel in the center of the board and it continued into the relief on the free end (if the nut was original, or if a replacement nut was removed, you could see the bridge through the channel).  I'm not at all sure if this was done for weight reduction, however, as they also put a screw in the upper block to secure the neck.

Concerning the free end: Is there more weight reduction with the double channel vs.a traditional relief in that area?  Just trying to get my head around it.

Cute cat.

 

 

[Deo Lawson]

Probably a similar amount of resurfacing potential to a super-thinned board to be honest.

How often does a board need to be resurfaced anyway? I play quite a lot and I hardly put a dent in mine, certainly not enough to justify taking off even 1mm after a few years.

[David Burgess]

In my experience, light fingerboards do nothing to improve the sound, playing properties, or projection of an instrument. More like the opposite.

[VicM]

8 minutes ago, David Burgess said:

In my experience, light fingerboards do nothing to improve the sound, playing properties, or projection of an instrument. More like the opposite.

Make the violin "false" for starters.

[VicM]

4 hours ago, Don Noon said:

My primary goal is to make instruments that are not obviously different from conventional high-quality modern ones, and within that constraint, have the best performance and lightest weight,

lightest weight = tone is weird, rattles in double stops and is FALSE. 

[uguntde]

Many Degani violins have very thin fingerboards. This has nothing to do with the sound, they can have/cause wolf notes though.

[M Alpert]

1 hour ago, Jeffrey Holmes said:

Concerning the free end: Is there more weight reduction with the double channel vs.a traditional relief in that area? 

 

I'm also interested in @Don Noon 's reasoning for this.

I've seen this on cellos and basses, and I understood that some use it to tune the resonance of the hanging part of the board. But if there is a more concrete theory, I'd love to know!!

I doubt it would be lighter, rather heavier...

[Jeffrey Holmes]

53 minutes ago, uguntde said:

Many Degani violins have very thin fingerboards. This has nothing to do with the sound, they can have/cause wolf notes though.

Many of the original Degani boards I've seen do tend to be on the thinner side.  That may be in part, though, to reluctance of a luthier to change an obviously original board combined with repeated planing and dressing over the last 100 plus years. 

[Don Noon]

5 hours ago, Jeffrey Holmes said:

Concerning the free end: Is there more weight reduction with the double channel vs.a traditional relief in that area?  Just trying to get my head around it.

On the free end (cantilevered over the body), the center spine just continues for a short distance, and then goes into the usual single scoop.  Full picture here.  Just to add a bit of stiffness where it's most effective.

3 hours ago, David Burgess said:

In my experience, light fingerboards do nothing to improve the sound, playing properties, or projection of an instrument. More like the opposite.

The question is:  where is lightness bad, and is it a mass or a stiffness issue (or both)?  I am attempting to keep stiffness similar to normal by removing weight near the neutral bending axis in the neck zone.  In the overhang area, I am NOT trying to minimize weight (normal thickness there), where reaction mass might be more critical.

You could save a lot of weight by cutting off the scroll.  I tested that... it's not good.

7 hours ago, Don Noon said:

My primary goal is to make instruments ... the best performance and lightest weight

3 hours ago, VicM said:

lightest weight = tone is weird, rattles in double stops and is FALSE. 

If that's true, then lightest weight is NOT the best performance.  Best performance comes first, so if less lightweighting performs better, that's what I'll do.  And it's why I won't try to lightweight the scroll.

[Marty Kasprzyk]

Martin Schleske has carefully studied the acoustic effects of the fingerboard thickness, length etc. See his website:

https://www.schleske.de/en/research/handbook-violinacoustics/fingerboard-acoustics.html

[Don Noon]

Yes, I know about the fingerboard modes and mode matching, and tried to find any real effects  in addition to the theoretical ones.  With extremely high-resolution frequency spectrum examination, I WAS able to see a miniscule effect with the much-ballyhooed A0/B0 matching, which was just a fraction of a dB flattening and widening of the A0 resonance peak.  This is what theory says the effect should be (although real-world tests are needed to find the magnitude).  But theory says the effect would only be for that one narrow frequency range, and becoming "lively" and "resonant" seems far-fetched.

My attempts to find real acoustic effects of the fingerboard torsional vibration mode yielded nothing.

My present working assumption is that more complex player/string/fingerboard interactions are more critical than simple modal frequency matching, with reaction mass and stiffness perhaps being the directly important factors, rather than the frequency. 

Yes, frequency is determined by mass and stiffness, but a high-mass, high-stiffness fingerboard can have the same frequency as a low-mass, low-stiffness one.  If they felt the same to the player, then the frequency matters most.  I assume they would feel different.

For now. 

[Andreas Preuss]

13 hours ago, Don Noon said:

 

My primary goal is to make instruments that are not obviously different from conventional high-quality modern ones, and within that constraint, have the best performance and lightest weight, while still being serviceable by folks like Jeffrey (and not having issues that need his servicing frequently).

For the lightweighting I'm currently doing, I save somewhere around 10 - 12 g on the fingerboard as modeled by my cat in the photo.  It's not a huge amount, but for 15 minutes of setup and runtime on the CNC, it seems worth doing.  There's still 3 mm minimum thickness above the pocket, to allow for some resurfacing.  For violas, its more weight saved and probably more important.

Do you get much resurfacing potential with a laminated ebony/spruce fingerboard??

 

Saving 10-12g on an ebony fingerboard is probably the maximum you can get. 
 

I see no reason why this might risk more frequent resurfacing and leaving 3mm wood for this purpose looks reasonably good. This would leave (at least) 1.5mm for resurfacing. Ebony might start feeling bouncy under the fingers at 1mm. Best way would to make a test with a player. 

Second option with CNC methods could be to make a ebony shell and a precisely fitting spruce core bonded together with gorilla glue. In case there are minor gaps between both parts the gorilla glue will ‘foam it up‘.

[Marty Kasprzyk]

10 hours ago, Marty Kasprzyk said:

Martin Schleske has carefully studied the acoustic effects of the fingerboard thickness, length etc. See his website:

https://www.schleske.de/en/research/handbook-violinacoustics/fingerboard-acoustics.html

I saw one of his violin is for sale at 36000$.