Concert ukulele fretboard

Hi all,
For a while now I have been building soprano scale ukuleles. I have built a banjolele which I am pretty happy with (five incarnations later but that is the way it goes at the start). I have recently built a solid body electric uke based on a 1958 gibson explorer guitar.

For the type of music that I want to play I decided to make my next instrument (modelled off a Gibson SG guitar) a concert scale. I bought a concert sized fretboard from ebay, and when I got it the frets were in noticeably different positions than the soprano scale.

My question is (sorry it took a long time to get there) is this normal? Is the concert sized fretboard different to the soprano? I assumed it would be the same just longer.

Your advice is appreciated.

Kind Regards,

Doctor dendro.

Yes, just like the tenor frets are bigger than the concert. Bigger scale = bigger frets. Ask in the luthier forum, I think figuring out exact spacing for the fretwire positions has something to do with the number 18, lol. Or 18 dot tiny numbers. Depends on who answers.

This might help
http://www.stewmac.com/FretCalculator

If you want a ready made concert fret board you can get one from Mike at Mainland Uke http://shop.mainlandukuleles.com/category.sc?categoryId=8

We will want pics!

Fret placement on a fingerboard is based on a ratio, being the placement of a fret is 1/18 (approximate) of the remaining measure on the scale. So, if you use the soprano scale of 13.5", the first fret will be placed (from a set of plans) 0.758" from the nut. The second fret will be placed 1/18th of the distance from the 1st fret to the saddle, 0.715". The third fret will be placed that 1/18 of the distance from the second fret to the saddle, and so on down the line. Because of the longer scale on a concert (15" on the plans I am using), the fret spacing will also be longer. For the above concert scale, the measurement will be 0.842", distance from 1st to second fret is 0.795", and so on. As scale lengths get longer, the spacing between the frets will also increase, as we're dealing with a constant ratio applied to the different scale lengths. I hope this makes some sense!

It can be difficult to get your head around, but is quite straightforward. You take the scale length, and divide it by 17.817 - that gives the distance from the nut to the first fret. Then you take the distance from that fret, and divide it again, to get the distance from the first to the second fret. When you have followed this sequence twelve times, your twelfth fret will be exactly at the half way point of the scale length. Then you have to add the necessary compensation (about 3mm for a soprano).

Or you can use 18 as the divisor, and not add any compensation.

With the first divisor you will end up with a slightly longer scale length than you started with - thanks to the compensation. Using 18 leaves the scale length at the original figure. Both methods give the required results.

Or, the Stewart MacDonald calculator will do it all for you.

John Colter.