If I measure the middle of the 12th fret to middle of the 13th and come up with 23/32 on this old Granada does this calculate to a 251/4 scale normaly? .Also just to verify that we are all on the same page when we take that nut to twelth double add 3/32 on high -E and then 1/8th on low E should these marks be the front of the 3/32" slot or the string touch points for the two E strings . Right now When I measure 2513/32" down the center of the board that puts me right at the front where the old rosewood bridge was glued on the the soundboard! Does that mean its right or way out?Thanks all for getting this straight for all the pickers out there trying to make their axe sound like the perfect intonation on Nanci Griffiths Taylors when she hits those high -E ,12th fret harmonics capo on the 3rd fret in drop -D tunning playing Love At The Five & Dime -Rob (AKA - nanccinut)

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If you want to know the scale length on the Granada, it's easier to just follow Ron's advice and measure from the nut to the center of the 12th fret then double it. I learned the hard way that fret positions must be measured with as much accuracy as possible. For me, measuring fret to fret to the closest 32nd isn't accurate enough. There are just too many compound errors.

To me, Intonation has more to do with sound than distance. Guitar setup appears to have a lot to do with final intonation. High and heavy strings need more compensation than low and light strings, plus I've read that some builders make their intonation just a bit flat intentionally so I think you are in a better position than anyone to tell if your Granada plays in tune.

Maybe someone else has better information than this, It's just my opinions.

Using the table on page 268 of Cumpiano & Natelson, let x be the length of the scale. On your guitar the distance between the 12th and 13th frets is 23.32, which means that 0.528063x - 0.5x = 23/32 = 0.028063x. That means that x = (23/32)/(0.028063) = scale length. I.e., if your measurement is EXACT, your scale length is 25.6" (~25 19/32"). Alternatively, you can just calculate the distance between the 12th and 13th frets for a 25.6" scale from the table: It is 46/64 = 23/32" -- just what you measured.

25 13/32"+ 3/16" is pretty close to 25.6". If your scale is really a 25.6", it means that if it should be 3/16" from the front of the bridge to the front of the saddle. The adjustments at the high & low E depend on the compensation that the luthier decided to use on the saddle, so it is more difficult to analyze those measurements.

Thanks Gary so if I am reading all your great math correct I do the following as measurement to be correct!
Down center of fretboard I should measure from nut to center of saddle touch point exactly - -25 - ?/32 "if you can help me out get it perfect Gary
Then making sure using front corners of wings on bridge square to frets I should get the natural comensation of the slot correct which Iam sure Martin has got dead on by now.Thanks again for that final exact nut to center saddle scale length Gary in advance. Just want to get it dead on! -nanccinut
No problem, glad I could help. The length from the nut to saddle between the D and G string is 25.6" = 25 19/32 + a hair. You will be good with 25 19/32, since the error is less than 1/64" -- not measurable for most of us. :-)

That is exactly how I set my bridge -- the front edge is parallel to the frets, and I use a compensation that I measured off of a few Martins.
Thank you so much Gary for that great math work. Just out of curiosity will see how my good Rhode Island D-35 Guild matches up to that even though I realize that mulity number may be a tiny bit different. Will write that number down before I loose it.- nanccinut
Gary if I give you the exact nut to middle of the 12th fret can you calculate to be sure of my fret to fret measurment what the exact nut to middle of the saddle touch point should be with HUGE thanks? -ROB
Gary if the exact nut to center of 12th fret is 12 -26/32nds then What is the nut to center of the saddle exact final measurment if you can check again with HUGE thanks? I have to assume all the fret board has shrunk equally and just a touch over the years in this 30+ year old relic slowly throwing its intonation out .-Rob
Classical guitars have their scale measured millimeters rather than inches. 650 mm is often used on a classical guitar, and 650 mm = 25.59055" -- people usually just say that a 650 mm scale is 25.6".

If you measure 12 26/32" from the nut to the 12th fret, the exact length between the edges of the nut to saddle (between the D and G strings) should be 25-5/8" (in decimal, this is 25.625") Now, if the scale is supposed to be 25.6", the nut to 12th measurement would be 12.8 (12-51/64" or about 1/64" less than 12-26/32"). If the scale is supposed to be 650 mm, the nut to 12th measurement is 325 mm, or 12.795" (a tiny bit closer to 12-25/32" than to 12-26/32"). If this is classic guitar, the original scale was probably 650 mm. If it is an American steel string, it was probably a 25.6". I would say that with the tolerances of old wood, either measurement is justifiable.
Thanks again Gary nut for helping me match as close as the fretboard I have on this Japan Granada Martin copy to a 64- D-18 .
Going with your final center nut to center saddle as 25-5/8 inches measurment to re-attach the bridge here allowing exact intonation slot specs from Martin to get the rest of the strings right.
Looks like a 64 Martin had a 16 " radius fretboard which I assumed they matched on the original ivory saddles with no intonaton Martin did tell me. Anyone know what for sure the total height a 64 saddle was in decimals and how much cleared the 10/64th slot? This depth was given to me by Martin but was also given .225 by a luither. Which depth is better?
One last question after reading this better to be a touch flat theory. Given the old fret board which even though appears straight with no tention on it my guess thirty lbs of string pressure will sharpen the whole aquasion just a tap. Would you add another 32nd or more to the 12th to center saddle length anyone to off -set this assumed sharpness once strings are tuned to pitchor go with the 25-5/8 measurment?
Oh, sorry I didn't know this was a D-18 style guitar (I didn't even know about the Granada Martin). The standard D-18 has a 25.4" scale, with the following measurements for the first 12 frets (from the nut): 1-27/64, 2-49/64, 4-3/64, 5-15/64, 6-3/8, 7-7/16, 8-29/64, 9-25/64, 10-19/64, 11-9/64, 11-15/16, 12-45/64.

Good luck on the restoration.
Thanks again for that great math. Now that I know my nut to 12th on the Granada /Martin copy is a bit longer being 12-26/32" or 12- 52/64ths or 7/64ths longer here is the real stuipd question. Should I just go your calulation to make the guitar sound its best orsplit the difference to move towards back of guitar another 3 -1/2 64ths .? My guess go with your previous calculaion Garry is that the best answer for a final down the middle nut to saddle measurement of ------ .
Huge thanks .
ps got my slot done and looks pefect.
Have you read he therad on Banjo hangout about the Gibson tempered scale with irregular measurements? Most Gibson copies use a 26.25" scale for whatever reason.


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