Compound radius FRETBOARD is incompatible with STRING/SADDLE RADIUS?

[Number Of The Priest]

Trying to wrap my head around something here.

Say you have a 12"-16" compound radius fretboard. The radius at the nut is 12" and the radius at the butt is 16". This forms a "wood cone" shape. This is the way I understand it.

Therefore, because the saddles are beyond this 12"-16" wood cone, the bridge/saddle radius should be set even larger (flatter), like 18" or 20"? (I haven't done the math but I suspect this is why understring radius gauge sets include gauges up to a very flat 20".

If you set the saddles to be 16", you are decreasing the radius of the strings at the 22nd/24th fret. The strings at the 22nd or 24th fret will have a radius between 12" and 16", while the wood and frets will be 16". A mismatch.

Thoughts?

Or have I got it all wrong and the fretboard is carved in such a way to reflect a 12"-16" nut-to-saddle cone?

[sully]

No, you're right. Now throw a floyd into the mix, which has a 12" radius without the shim under the saddles. It shouldn't work, but it does.

[rjohnstone]

Yep... my Floyd's are all shimmed to match the correct radius.
It is 20" at the trem (just rechecked it with a gauge) for a 12"-16" neck.
If you ever run into string buzzing while setting up your Floyded guitar, add shims as something to check.

[Number Of The Priest]

Thanks gents. Based on your input, a guitar listed as 12"-16" radius has a "wood cone" of 12"-16", but the "string cone" is actually 12"-20".

And if a Floyd comes with a 12" radius, then the outer string saddles need shims (if not already installed by the builder) to flatten the radius of the whole bridge.

That was easy.

[Catharpin]

Excellent info!
SO given it should be a 20" radius but is a 12" how much do I need to shim the E/E and the A/B?

[xenophobe]

Most people just adjust the bridge so the minimum string height clears... it's not a big deal. If it really bugs you or you want your action set as low as absolutely possible... then shimming is what you would want to do. It's not necessary and in most situations you'll never notice the difference unless you sit there with a ruler or string height gauge.

[DonP]

Most people just adjust the bridge so the minimum string height clears... it's not a big deal.

Yep - the action will be higher on the non EE strings in the middle.

[toejam]

No, you're right. Now throw a floyd into the mix, which has a 12" radius without the shim under the saddles. It shouldn't work, but it does.

Are Floyds 12" without shims? I thought they were actually 10". Or is it just the nuts that were a 10" radius?

[Newc]

Before shimming the outer saddles, be sure the inner saddles aren't shimmed.

As for the "cone", the saddle radius is flatter because it is so far beyond the end of the fretboard, which stops at a 16" radius.


The radius of the nut isn't so much a factor at the first few frets, as long as it's within 2" (10" nut 12" radius), as you've also got the string height to consider. Fretting notes at the 1-5 is not noticeably more difficult just because of the difference in the radii. A 12" nut would probably work against you in the long run due to neck flex and bow/relief.

[jspeed]

Wow, great topic, looks like it's time to saddle up! lol

[rjohnstone]

Before shimming the outer saddles, be sure the inner saddles aren't shimmed.

This... I picked up a Floyd off of eBay that was shimmed to fit a 9" radius board. The center saddles were a lot higher compared to the outer ones.
I Believe it came off of a Fender someone converted to an OFR.

[sully]

Keep in mind that a Floyd nut's radius is 10. You just can't win.

[Axewielder]

Now throw a floyd into the mix, which has a 12" radius without the shim under the saddles. It shouldn't work, but it does.

I thought the radius is closer to 12" when that factory shim under saddles 2 - 5 is installed, then with it removed it flattens out and is closer to 16". Jacksons always have the shim removed on account of that. There is a ton of contradictory information on this, even on the Floyd site.

[1337storm]

I allways put shims under the E, A, B, E strings on my Floyded Jacksons.
Many will say it isn't necessary but to me it just feels better to know that the shit matches.

[Newc]

Only Floyd I ever had with shims under the saddles was one I bought new a few years back. None of the ready-made guitars I bought had them. They fell out when I was setting the intonation, and I was like "dafuk?"
Put them back under the saddles and the action in the center was way too high for a Jackson, so I had to undo it all to get them out again. That sucked.