Official Luthiers Forum!

http://bluescreekguitars.com/blog/

Hi - Excuse my ignorance but can you explain this process to a newbie like me.

John

I cant totally explain Johns method .. I dont understand why he doesnt just radius the whole thing ... I do, and it works fine for me. If Johns method works for John, well ... then it works for John. Its just different from how I do it. Serge DeJonge and Laskin/Larrivee use a totally different method, and geometry ... but they get it to work for them.

The 28 foot radius on the whole top gives you the 1/16 or so of clearance at the bridge area you are looking for. The angle the top makes with the sides at the neck joint is really irrelevant (although its pretty close usually to 1.5 or so degrees) .. I simply make it (cut the neck heel) such that the heel will sit flat on the body, and the FB extension sits flat on the top. for me, its that simple. The lie of the whole FB is now flat, no hump (I level, radius and fret the FB after attaching the neck in the white).

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

I use the method I do because the 3 separate areas actually create stiffness buy the shape. I can also control the bridge height best this way. I like to create the flat angled area for the fretboard , the area between the sound hole to the bridge is flat , and the lower area having the true radius.
Check out the vids and feel free to contact me with any questions
Video link http://www.youtube.com/results?search_q ... ues+creek+
john

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Do you use a flat UTB John ?? .. that would explain some about why you do what you do - I dont, mine is 28 ft radius.

FYI - Laskin and Larrivee use a flat rim, but the top's upper bout (bridge to neck) is radiused, the lower bout (behind the bridge) is braced flat .... at least they used to do it that way.

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Have you found the need to flatten the upper bout beneath the fretboard Tony?
Terry

_________________
It's not what you don't know that hurts you, it's what you do know that's wrong.

I use the flat side of the disk. I do flatten the upper as martin uses a flat brace here also. That is just the way I learned. I found that using the radius can make the control a bit more difficult of hitting the numbers I want for a straight transition
john

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

It seems to me that if the bottom of the fretboard extension is flat, then the board it sits on has to be flat, too. Or is the 28' radius flat enough not to be noticed?

Not to answer for Tony, but I do this procedure exactly as he describes and yes, I do flatten the area where the fingerboard will rest on the soundboard. The amount of wood that has to be romoved for this is very small, however.

_________________
Rian Gitar og Mandolin

Yes, flatten the top area .. like mentioned its about 4-5 thou only ...

Rick Cowan (a newer OLFer) set the neck on his build in the shop last night. The lie of the unfretted FB, still yet truly levelled and radiused, was almost perfectly sitting on top of my .345 "tester" bridge. The neck needs a bit more back set, which will get it perfectly lined up. It took about 20 seconds to flatten the top Fb area, longer to get the neck pitch almost right while flossing the fit. Rick was also working on getting the FB to drop down to a certain spot on the rosette, so a little bit of carving was required on the heel's upper portion to do that. We still have a bit of centreline work to touch up, but the inserts and bolts went in, and its looking good.

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Hi John

A few questions

If the back is tapered does the sanding disk sit flush with the sides, I am assuming you need some play between the disk and the guide/pole to allow it to settle naturally.
What dictates the position of the disk guide/pole
can you confirm that you put a radius along the x-y axis and then flatten it the lower bout
if the sanding disk has a radius then if you turn it thru 360 degrees wont that put a radius from side to side
how do you make the radius disk ?

Thanks

John

Hi John

A few questions

If the back is tapered does the sanding disk sit flush with the sides, I am assuming you need some play between the disk and the guide/pole to allow it to settle naturally.
What dictates the position of the disk guide/pole
can you confirm that you put a radius along the x-y axis and then flatten it the lower bout
if the sanding disk has a radius then if you turn it thru 360 degrees wont that put a radius from side to side
how do you make the radius disk ?

Thanks

John