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View Full Version : How well can you trust the fret boards of the American ukuleles of the 1920s - 1930s



Henning
07-30-2014, 03:04 AM
Hello, how true does an American ukulele play in tune from the 1920s to 1930s?
Yes, I am aware that this might differ concerning brands and individual instruments too.

The reason for me to ask this question is that I have an uke from that era and wonder wether I shall use the original slots for the frets or need to remeasure and mark up new ones.
What do you think?

Regards

gyosh
07-30-2014, 03:20 AM
Hello, how true does an American ukulele play in tune from the 1920s to 1930s?
Yes, I am aware that this might differ concerning brands and individual instruments too.

The reason for me to ask this question is that I have an uke from that era and wonder wether I shall use the original slots for the frets or need to remeasure and mark up new ones.
What do you think?

Regards

The original frets should be in the correct positions. If you want to adjust the intonation I would start withe nut and bridge. Much less work and should do the trick if I'm understanding your question correctly.

Henning
07-30-2014, 05:08 AM
The frets should be in the correct positions, that's true. But, what is there to expect?
The fretboard is going away in pieces.

ukantor
08-07-2014, 11:20 AM
I would definitely measure and check the fret positions. It is easy enough to do with one of the fret position calculators on line. I recommend the Stewart MacDonald one.

Measure from the nut to the twelfth fret, then double it to get the un-compensated scale length. If each fret is no more than a third of a millimetre from the given position, they'll do nicely.

Graham McDonald
08-07-2014, 12:08 PM
It would be worthwhile remembering that older instruments, I suspect up to the 30s at least, calculated their fret positions by the Rule of 18, simply dividing the scale length by 18 to get the first fret position and then repeating as required. Doing it that way builds in saddle compensation. The StewMac calculator will use 17.817 as the devisor which is more accurate but requires compensating the saddle (and maybe the nut). More important on steel strings than nylon.

cheers

ukantor
08-07-2014, 12:42 PM
It is misleading to state that using a divisor of 17.817 is more accurate than the Rule of 18. I have used the Rule of 18 on several ukes, and the resulting fret positions are within a gnats whisker of the positions given by the more "modern" divisor. Do a comparison and see for yourself. The differences are inconsequential.

Pete Howlett
08-07-2014, 10:16 PM
I've played John's rule of 18 uke and it intonates remarkably well

Graham McDonald
08-07-2014, 10:56 PM
I have my fret slot cutting template made to the rule of 18 and have made all my ukes (albeit only 5) using that. Works just fine. It is the simplicity of knowing where to put the bridge which is the appealing factor :D

Sven
08-08-2014, 01:21 AM
Just a recap for those who don't know it already - if you use the rule of 18 you use the actual string length and get the necessary compensation right away. If you use the 17.817 you work with the nominal scale length and add a couple of mm to compensate.

If I remember correctly (I will do an exercise in excel to test it), take 353 mm and use 18 and the fret positions and the bridge position will be more or less equal to the case when you use 350 mm, 17.817 and then add 3 mm for compensation.

Sven
08-08-2014, 01:49 AM
Well I did run it through excel and I'm not very good at it. I compared a 352 mm string length with the rule of 18 applied, and then 350 mm scale length using both 17.817 and a more exact number wot i found on the internetz; 17.81715375. The numbers given below are fret-to-fret distances for 15 frets.

The minor discrepancies seem to be less minor at the first few frets.


Rule of 18 17,817 17,81715375
352 350 350
19,55555556 19,64416007 19,64399056
18,4691358 18,54160857 18,54145809
17,4430727 17,50093907 17,50080601
16,47401311 16,51867836 16,51856124
15,55879016 15,59154818 15,59144564
14,69441293 14,71645427 14,71636504
13,87805665 13,89047603 13,89039894
13,10705351 13,11085679 13,11079075
12,37888387 12,37499459 12,37493861
11,6911681 11,68043352 11,68038667
11,04165876 11,02485551 11,02481694
10,42823327 10,40607257 10,40604151
9,848886978 9,822019558 9,821995281
9,30172659 9,270747202 9,270729045
8,784964002 8,750415654 8,750403005

ukantor
08-08-2014, 02:30 AM
I haven't checked 'em, but those numbers look right, Sven - and I trust you.

So the largest difference is .0886mm - less than a tenth of a millimetre. Who can cut that accurately? How much movement do you get as wood dries or re-humidifies? If you COULD cut fret slots with that sort of accuracy, who would be able to discern the difference, by ear?

Check out the difference in the note at a given fret, as it varies with changing the pressure of the finger holding down the string. It is a huge variable, compared with moving the position of a fret by .0886mm - if you could.

I rest my case. The rule of 18 works perfectly. As does the mathmatically "correct" divisor, once compensation has been applied.

John Colter

Henning
11-02-2014, 01:31 AM
Ok, thanks guys, I understand this about compensation of the saddle and the source of why that is necessary. But I don't understand the reason why the nut should need to be compensated.
Can anyone please explain that and how is it done?

Is it simply because of the different string dimensions?
Then each fret ought to be compensated too....