On your question about Fretting....I dont have the right saw so I used what I had in stock which was a metal saw(smaller than your normal wood saw blade). The blade was still too big but not big enough that it would wiggle around in the slot. I then applied glue bond and cleaned off the excess. In the future I will purchase a proper fretting saw but for now this is my way and only way.
The reason I mentioned about measuring the distance between the nut and the bridge was to make the positioning of the bridge on your new instrument much easier. If you are building a fretted instrument the scale length - and so the position of the bridge - is all relative to the positioning of the frets. With a small scale length (the distance between the nut and bridge) such as a ukulele, this positioning can affect the intonation of the fretted notes quite appreciably.
If the bridge is perhaps 1/4" out, the notes played by the fretting of the strings will not be correct. Ukuleles don't usually have adjustable bridges like you might find on an electric guitar so there is little chance of any adjustment once the bridge is in position, unless you use a bridge and tailpiece like (for example) a banjo..
There are however several computer applications that would allow you to formulate the correct dimensions. Check out the scale lengths group on the.nation's groups section.
I hope this answers your question and that I haven't made the question more difficult?
thank you very much for adding me as a friend on cigar box nation.
I see that you would like to use a soprano uke neck with a cigar box. Please make sure that you have a substantial block of wood inside the box where the neck joins the box .I then screw the neck to the box from the inside, or you can get a special screw that you screw into the neck and then bolts to the box. these are really useful as the neck can be detached from the box. just use a dowel or something in order to keep the neck "SQUARE" to the box.
For this guitar - and the stand up bass - I used what are known in this country strimmer lines of different thicknesses. I understand that over there they are known as weed whackers or bush cutters. These are nylon lines that are used on machines for cutting down long grass and scrub type plants. Initially they stretch - like ukulele strings - but once the stretc has been taken up, they stay in tune very well.