My first CBG design. Here are my thinking aloud thoughts:
I was keen to have a 300 x 200 box, with the bridge about 60mm in from the rear side, allowing for plenty of vibration area on the box.
To get a 648mm (25 1/2" ) scale length, from nut to bridge, seems to be a popular scale length, I found that I would need a fretboard length of 648 -(300-60) =408mm (16 1/16") long, and allowing for a 4" headstock, the overall length of the guitar would be 300 +408 + 102=810mm (31 7/8").
Next step is to work out the fret spacing for a 408mm (16 1/16") long fretboard, and how many frets I get?. Can anyone please advise how I go about calculating these. Modestly, I am a bit good at Maths, except when it comes to Probability :)
The alternative would be to use a scale length of 610mm (24") and a fretboard of 440mm (17 5/16") long, and I found the fret spacing for that - see attached. But it would mean either shifting the bridge 38mm toward the centre of the box to give a 610mm (24") scale length, or not do the last few frets on the 24" fretboard.
So now, this is where I am at - twisted myself in logical and mathematical knots, and not quite knowing what to do.
I would appreciate some sensible suggestions on the best way out of this please
Cheers,
Jill
Replies
Moving the bridge towards the middle isn’t bad, it actually gives more vibration than having it towards the end? Look at a guitar, the bridge usually sits 2/3 back from the front of the body to optimize string vibration? How many frets do you have to cut out, if it’s only a few, I doubt you’ll miss them? Fretscale calculators & templates are easily found on the internet, like the Stewmac calculator or FretFind2D, which gives the option to print a physical layout rather than measurement info?
Thanks BrianQ, you have help me decide to move the bridge towards the centre, which is not really a big problem as it will still be only 1/3 of the way from the back edge to the front edge. ( or 2/3 from the front, as you indicated acoustic guitars are)
I was unaware that the bridge should be placed where there is greater vibration, thanks for that. I really need to understand /learn the theory of guitars better.
Thanks for the info on Fretscale calculators, never knew they existed.