How Flat a Radius to not fret out w low action?

[tribalfusion]

Does anyone know technically how flat a guitar's radius needs to be to bend without fretting out if the action is in the 2 or 3/64ths of an inch range like Holdsworth's action on a neck with little or no relief?

Is 16" a flat enough radius or does it need to be 20" or higher? Allan himself uses a 25" inch radius and his signature model is a 20" radius though he himself doesn't bend much these days...

Thanks

 

[Bloozcat]

Well, a 9-1/2" radius will do it, but if you're building a guitar with a choice of radius you can go with a flatter one, like a 12" to a 15", for instance (or more). Or, you can opt for a compound radius like a 10"-16".

I personally prefer a straight 10" radius because it's as important to me to have a more curved radius for chording, especially at the lower frets. I have no problems with the strings fretting out.

It's a matter of preference what one chooses.

 

[ZMAN]

The flatest radius I have owned was 15 on a Telecaster FMT HH. It was pretty flat. I use finger vibrato and bends on every note so I really need a low action and flat radius. I find my 12s on the Gibbies are just about perfect.
I can't even imagine a 25. Most strats are ok at 9.5 as well.

 

[marnold]

I really like my Jackson's neck. It's got a composite radius that starts out at 12" near the nut and ends up at 16" toward the body. The flatter the better for me. I don't have a ton of experience with more curved fretboards but a 9" would drive me nuts for the reasons you mentioned, to say nothing of a 7.5".