Fingerboard radius?

[edpal]

Originally Posted by Nagrom

If you draw an arc with a radius of 150mm, then scoop the centre by 1mm, you now have an arc with a radius of 151mm, and a relocated centre point that has moved 1mm farther away from its previous position. So sayeth the AutoCAD.

AutoCad is incorrect. You still have a radius of 150mm, just with a scooped center. A radius is the description of a portion of a circle being drawn a partucular distance from a center point. Extreme example. 1/2" radius...drawn for 180 degrees is 1" across. Scooping out the center 1/4" would still leave it 1" across.....just looking like a big set of, of....camel humps! LOL

[Badong]

Subscribed.

[Matthijs]

Originally Posted by Pentabass

How do you measure the radius?

1. Hold various known concave perfect radius templates against the fingerboard?
Then, what about the 'high points' and the lower points, of the 'C-Kante' - in the asymmetrical shaped ?
2. Trace out the fingerboard measurements on a piece of paper and find the center of multiple perpendicular lines?
3. Start from the strings (since they are a known thickness, and perfectly straight) measure their radius (string centre to centre), and then give the fingerboard relations to that?
4. Any other methods?

I find it particularly vexing to get a radius measurement at the nut.

Yes I know: ancient thread. but I saw nobody answered this.

This formula allows you to calculate a radius:

Measure the distance from one end of the fingerboard curve to the other end and divide this by 2, we'll call this C.

Measure the height of the curve in the middle between those two points, we'll call this H.

Radius= (C squared/(H*2))+H

Taking those measuremens really accurate is difficult, so the result will in most cases be off, but will be close enough to round it off to a standard size. you can check wether that standard radius fits afterwards.

[JoeyNaeger]

Just fyi, but it's pretty uncommon that fingerboards and bridges are cut to a perfect radius.

[RCWilliams]

The geometry of a finger board is more complex than it looks like it should be. the out line of the finger board is parabolic along each side, the edge should remain the same height along its length, the scoop should vary across the across the board. a single radius would cause the scoop to be too extreme in the middle of the board.