Official Luthiers Forum!

Hi -

I was about to glue my bridge when I decided to measure the position of my saddle against the nut and saw that using the fret rule - it is 653mm. My finger board is slotted for 650. Why is this ?!!!!???? I can just use the mm side of the fret rule to measure - but it is annoying because now the fret locations are all for 653 on that ruler, and I needed a fret ruler for 650mm or 25 21/32" arggh !!

is everybody's IBEX like this ? you can test by making marks on the wall a the nut location and the saddle location - then measure beteen the marks using the mm side of the ruler.

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It's this new idea from recent decades that everyone gets a participation award. - MUX

I'm not familiar with this product, but it seems that it might have 3 mm compensation built into the nut-to-saddle dimension. 2 or 3-mm compensation is pretty much standard for a 650 scale; thus, 653 mm would be a desirable nut-to-saddle dimension. Just verify that your 12th fret is located at 325 mm, and all is OK.

But when I line up the frets part of the ruler to my 650 slotted finger board - all is fine till about the 12th fret then the ruler goes a little more and more further south of the slotted board fret location. My 650 slotted board is from stew mac. Due to my fretboard being slotted like this - then should I stick to 650mm ?
Cumpiano as well measures 25 21/32 which is 650mm, not 653.

So I am not understanding compensation - my classical is 650mm from nut to saddle. why would the fret ruler want me to make it 653 ?

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It's this new idea from recent decades that everyone gets a participation award. - MUX

John, I don't have one of those, but 3mm is a typical amount of compensation for a 650 mm scale. The saddle is typically set back 3mm or so to compensate for string stretch while fretting.
So if you can look at other 650 mm scale lentgth instruments, they will more than likely have their saddle at 653 mm.

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Jim Watts
http://jameswattsguitars.com

John,

If you look at the saddle end of your Ibex fret rule, it tells you that the compensation is included in the saddle locations. If you look a little further to the left, it also tells you that the string length dimensions next to the scale lengths symbols, do not include comp.

Bob

But why do the fret locations not match up with my stew mac 650 scale length fingerboard? My current classical (Sanchis) is 650 between nut and saddle.

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It's this new idea from recent decades that everyone gets a participation award. - MUX

I recall reading another OLF thread a few months ago where this very question was raised. If I recall correctly, the general concensus was that the old IBEX rule has frets in the wrong positions and the newer Stewmac template is correct.
I'd do an archive search for this thread if I were you.

Cheers,
Dave F.

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Cambrian Guitars

"There goes Mister Tic-Tac out the back with some bric-brac from the knick-knack rack"

The 25.34 scales line up on both Ibex and StewMac, but on the StewMac, the other steel string scale is 24.9, while the Ibex is 24.84, so they don't line up.

Bob

I just checked the Ibex classical scale and it states it is 25 21/32" which is 651.66875mm. I checked between various frets with a digital vernier, and the distances are accurate, according to StewMac's fret position calculator.

Bob

Certainly my old version is inaccurate, at least it is on the mm scale. Out by 2 mm's over the length, checked against two high quality rules.

The Courtnall book advises to add 2mm to the saddle position to compensate for depressing of the strings. If one uses the exact 650mm it could be noticed (slightly out of tune especially the notes after the 12th fret).

3mm sounds way too much to me, the high trebles will be noticeably flat. 2mm is the best compromise for nylon strings, but if you use carbon strings again they will be flat. I am very happy with how I do it, a slightly slanted saddle. The high E comp is just 1mm, which with different saddles can accommodate both carbon and nylon. The bass end is moved back by an additional 1-1.25mm.

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Build log

so on mine - instead of putting the saddle back at 650 - I will go down two mm and set it at 652 ? I just want to confirm before I glue it. Thanks

- Cumpiano/Natelson does not mention an extra 2 mm -I guess it is something minor that they skipped

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It's this new idea from recent decades that everyone gets a participation award. - MUX

Yes, 652mm measuring from the nut. It is not minor at all, without compensation all upper positions will be noticeably sharp.

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Build log

In my copy compensation is indexed on on pgs 9 and 39, quoting 0.10" for classical of scale length 25.6" in the layout section.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

got it - that explains why in the chapter about placing the saddle position - he mentions it is 25.7" for the classical.

I guess I will just use the mm ruler side of my IBEX ruller and then measure 652 from the nut. Why would they make a nonstandard size of 651 ? ugh...

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It's this new idea from recent decades that everyone gets a participation award. - MUX

FWIW, I use the old Ibex fret rule as well and I have absolutely no issues with it's compensation. All the classicals I've made with it have totally acceptable intonation.

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

At 650.24mm, 26.6 inches is pretty close to standard.
Maybe just easier than writing 25.590551181102363 inches!!
Also I noticed that 26.7 inches converts to 652.7799999999999 mm, pretty close to 653 mm.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I understand the above - but I do not understand how the frets would be off than the locations for a standard 650 scale, unless it was for a different scale.

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It's this new idea from recent decades that everyone gets a participation award. - MUX

Sorry, can't help you there

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I mesured on the rule and what Waddy said is correct. The scale seems to be more around 651-652 (the 12th fret mesures short of 326ish). So 653 mm would be a correctly compensated saddle for that scale.

Like I said (and as Waddy said), there is not intonation issue with this scale.

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

Seems to me that if you used a stewmac slotted board you'd want to use one of their fret rulers instead of the Ibex.

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"Preoccupation with an effect gives it power and enhances the error"
from "Your Owner's Manual" by Burt Hotchkiss.

If you use the IBEX, use it to place the frets and the bridge, and all will be fine. If you use it for one or the other, and use a different fret placement method, or a different compensation, you'll be off. It is a perfectly good rule, and intonation on my guitars that I used it on has been very good. I now use efret and compensate about 1mm to the front of the saddle, and use a double compensated saddle, a la David LaPlante.

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Waddy

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