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I'm thinking of placing an order with Stewmac for a radius caul for the fingerboard now I don't know the difference in playability of compound over radius a plain cylinderical radius as none of the guitars I own have it and a friend with gauges measured the 2 I play the most and they were both 12" radius, I was just going to get a 12" but then though should I get a 12" and say 20" to form the compound radius board.

All opinions welcome as I'm uncertain at the moment what to do

Thanks

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Formerly JJH

I learn more from my mistakes than my successes

Some people swear by them, but I think the advantages of a true compound radius are largely lost in an acoustic guitar. Now, if you are an electric shredder, then yes.

I use a 12" cylindrical radius, but when I level my frets, my leveler follows the string paths, so I end up with a psuedo compound radius.

I have never made a compound radius my self but I think you will want more then just a 12 and a 20. Maybe throw a 16 in there as well to grade it a bit more evenly, I could be wrong.

Never felt any need for anything other than a 16" radius. Classicals and lutes (wider boards) I was happy with flat.

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

I like a 16" radius fretboard, but if you like 12", then thats what you need.

Chuck

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I just wanted to know common sizes and what people felt comfortable with because I'd only played 12" radius boards if most people wanted 14" I'd of got that size

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Formerly JJH

I learn more from my mistakes than my successes

Just for reference, I'd say that more than 80% of the boards I sell to both acoustic and electric builders are 12" radius, and then the remainder is split pretty evenly between compound and 16" straight radii (generally all the compounds are for electrics and the 16" ones are for acoustics).

If I had to be stuck with one radius template, then, it's pretty clear which would work most of the time

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

John,
Not sure you are aware of this, but we just released a new fretboard radius jig this week. It comes with 4 radii - 12, 14, 16, & 20". You must have a thickness sander or drum sander with a 3" opening, but if you do, it may work well for you. It won't do a compound radius, but will get you really close. You can see images and video of it in action here:
http://www.luthiersuppliers.com/products/p12.html

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Tracy
http://www.luthiersuppliers.com

I use a compound radius. Usually 12" at the nut and 16" at the other end. I made an adjustable jig to radius my boards with a router. I can do anything from 10" to 20". IMHO if you do everything else right you won't see a big difference in playability it's just the way I choose to do it.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

well i have no experience to back this up but if you use a compound radius that matches the taper wouldn't you eliminate the need to level the frets?

btw, the compound radius jig i have is probably the easiest and least time consuming jig i ever made.

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Frank

[quote="Frank Aarre"]well i have no experience to back this up but if you use a compound radius that matches the taper wouldn't you eliminate the need to level the frets?/quote]

No, that has nothing to do with fret leveling.

I doubt you could ever completely eliminate the need to level the frets, but good preparation, reguardless of radius makes leveling the frets alot easier.

It took me ~30 minutes to make my compound radius jig.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

i realize that theory and practice don't always go hand in hand, but why wouldn't it eliminate fret leveling 'in theory'.

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Frank

Fret leveling is used to remove minor differences in fret heights caused by slight material thickness discrepencies and installation technique. It really has nothing to do with whether you have a cylindrical or compound fretboard radii.

Ok.

I haven't gotten to the point yet where i can see this for myself( working on my first), i've just been trying to imagine how a straight line that follows the fretboards taper will lie in relation to the frets, and in my head that line is running with an equal distance down to the frets on a compound radius, but won't on a cylindrical radius. I thought this was what you corrected with fret levelling.

My reasoning may very well be flawed, so those of you who know what you are talking about does my thinking make sense?

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Frank

No, you're perfectly right in your thinking. All single radius boards (and most compound radius boards as well) are machined as such that they do not provide a constant line under each string. They would effectively be in backbow under the outer strings when straight under the center ones. I haven't done the math, but I'm guessing the discrepancy may be as much a thousandth of an inch or so. In practice however, the effect you're referring to is relatively minor compared to other issues that usually mandate a dressing on new frets.

The main issue is simply that the idea of pressing rolled shape wire in to slots on a piece of wood, and holding to a perfect level surface is kind of a pipe dream. It all depends on your definition of perfect though, I guess. If perfect for one person means ±.0015", then you may be able to pull it off just fine without a dressing. If your goal is ±.00025" (at least over shorter spans), then you have to at least kiss the tops when you're done, regardless of how perfectly you install them.

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Eschew obfuscation, espouse elucidation.

Thank you David for explaining,
and sorry John for snatching your thread...

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Frank

Exactly what I wanted discussion over an area I'm uncertain of

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Formerly JJH

I learn more from my mistakes than my successes