Scale Length Questions

[Mike OMelia]

The plan set I am working to specifies a 13 15/16" scale. I thought I ordered a blank finger board from stew mac, but its cut (according to site) a 13 7/8" scale, 29 frets. I cannot image 1/16" would make a difference. Since the bridge is hand positioned, does it matter?

And, is there a radius on one of these?

Thanks!

[rcc56]

No, a 1/16" difference should not cause a problem on an instrument with a floating bridge.
Any difference would be aesthetic, and most people wouldn't notice if your bridge was located 1/16" farther forward from its ideal location in the plans.

Bill Collings was said to have an eagle eye, and purportedly would notice an 1/16" aesthetic difference from across the room.
But he won't be looking over your shoulder while you build your mandolin.
So don't worry, and enjoy your build.

If you really want to, you can a] shorten your neck 1/16", or b] order a 13 15/16" board from another supplier. I'm sure someone has a use for a brand new 13 3/4" board, and would take it off your hands for the same amount you paid for it.
To me, that would be more trouble than it's worth.

Unless you ordered a radiused board [which adds $18 to the cost], they will ship a flat board.
Currently, they show the radiused board as being out of stock.

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Fixed bridge instruments are another story. A 1/16" error in bridge location/nut location/scale length would cause noticeable intonation problems.

A few years ago, I bit the bullet and coughed up the cash for a slotting jig to enable me to correctly fill and relocate the saddle slot on Martin guitars with misplaced bridges without removing the bridge from the guitar. Yes, the tuning problems with thousands of Martins are not due to poor tuning machines or operator error-- Martin mislocated the bridges on many of their instruments for many years. I get several calls a year to execute such a repair.

[Mike OMelia]

But, should I radius it? And if so, how many inches?

Thank you!

Mike

[Dave Cohen]

Re Should you radius it?: No simple answer there. Depends solely on player preference. Are you planning on selling the mandolin? If so, my experience with commissions has been that more players currently want a radiused fretboard. Although, there are still players that prefer flat fretboards. I wouldn't even want to guess what the ratio is for those who prefer radiused versus those who prefer flat. I just don't have a large enough data set. So you are taking a chance either way.

If radiused, then what radius? That's another matter of preference. I have most commonly done fretboards with a 9.5" radius. Another popular choice has been the "conical" or "compound radiused" fretboard. If you are planning on making more than one mandolin, It's easy to make a concave sanding board to do your own fixed radius. That will save you the $18 every time. Also, if you search the archives for this part of the forum, you will find a description for a jig for compound radiusing to be used with a vertical belt sander. I think it might have been by Jim Hilburn, though it was quite a while ago.

[Mike OMelia]

OK, that helps a lot. I build acoustic guitars, very well versed on the issue there. I will ask client if he has a preference.

Thanks!

Mike

[Jim Hilburn]

If anyone in the Denver area wants that radius jig PM me. It's free for the taking.

[j. condino]

Don't sweat it. Most people move the dovetail back more that 1/16" trying to get the correct fit on their early builds!

[HoGo]

BTW, no one really knows what Gibson mandolin scale really was intended to be. They claimed 13 15/16" in their booklets but in reality it was closer to modern 13 7/8" boards but the imprecision of fret cutting makes it hard to decipher even what formula was used or rounding errors they did. I've got F-5 and F-4 borad measurements (each fret to fret) and thay don't even match each other too well (instruments are 1 or 2 years apart) but some patterns in deviation from 13 7/8" scale are similar.