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| Sanding Sides to Ensure Flat Fingerboard... http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=37183 |
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| Author: | sdsollod [ Mon Jul 23, 2012 1:49 pm ] |
| Post subject: | Sanding Sides to Ensure Flat Fingerboard... |
When radiusing the sides, it was my understanding that the top (sides) needs to be sanded at the upper bout to flatten out the area under the fingerboard extention. Frank Finoccio does this in his video and I have done this before. Frank puts a 1/8" or 1/4" strip of wood under the lower bout to raise the body up while sanding the top upper bout (sides) on a flat surface with sandpaper stuck to it. This positions the body at an angle to create this flattened area. In watching Robbie O'Brien's steel string video course I don't see him doing this... Seems like if you don't do that the fingerboard extention will have more of a bend rather than being flat where it joins the body... Why doesn't Robbie show this? On my current build, I did this process but it appears I have more of a bend than I would like. Again, I'd like the fingerboard to be flat from the nut to the end towards the bridge... maybe I didn't make enough of an angle... |
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| Author: | SteveSmith [ Mon Jul 23, 2012 2:37 pm ] |
| Post subject: | Re: Sanding Sides to Ensure Flat Fingerboard... |
Some people build with flat braces in front of the soundhole that helps with the fretboard lying flat - I have not tried that yet. |
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| Author: | Fred Tellier [ Mon Jul 23, 2012 6:03 pm ] |
| Post subject: | Re: Sanding Sides to Ensure Flat Fingerboard... |
Flat UTB brace and sand sides flat flat for me. I put a 24" sanding disk on the flat side of one of my radius sanding dishes, prop the butt end up to get the needed angle for the fingerboard extension an sand flat to the waist. Hesh had a tutorial on this a few years back |
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| Author: | bluescreek [ Mon Jul 23, 2012 6:25 pm ] |
| Post subject: | Re: Sanding Sides to Ensure Flat Fingerboard... |
Same here check out this link to see me doing it. http://www.youtube.com/watch?v=LrgRKKsxL-M It is all about geometry control. |
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| Author: | sdsollod [ Tue Jul 24, 2012 9:14 am ] |
| Post subject: | Re: Sanding Sides to Ensure Flat Fingerboard... |
Bump... Does anyone have any further comments? |
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| Author: | jfmckenna [ Tue Jul 24, 2012 10:08 am ] |
| Post subject: | Re: Sanding Sides to Ensure Flat Fingerboard... |
Maybe Robbie uses a thicker fret board and a thinner bridge? IDK but it's always difficult to get that just right. Fretting and profiling the fretboard after the neck is set helps take a bit of that out as well. IF the angle is too severe then you can shim it with a wedge under the tongue. Some people don't like the look but if you use the same material of the fretboard it hides it pretty well. |
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| Author: | Quine [ Tue Jul 24, 2012 12:45 pm ] |
| Post subject: | Re: Sanding Sides to Ensure Flat Fingerboard... |
Sanding the rim is just to match the neck angle. Some people build with no neck angle....90deg to the body. Most steel strings have around 1 degree neck angle. A little trig can get you the shim thickness you need. If your angle is 1deg and your body length is 22" then tan(1) *22=.38" close enough to 3/8th |
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| Author: | sdsollod [ Wed Jul 25, 2012 8:18 am ] |
| Post subject: | Re: Sanding Sides to Ensure Flat Fingerboard... |
Okay - I've been thinking about this and what I can do at this point to flatten the fingerboard extention... I fitted the neck and fingerboard before finishing and the fingerboard at that time appeared to be flat. Now that the finish has been applied the fingerboard extention is not flat along the same plane as the the rest of the fingerboard. I taped off the area under the fingerboard extention leaving approx. 1/16" (possible at little more) of the finish under the extention and have removed the tape in preparation for neck attachment. Perhaps the finish is thick enough to cause the bend at the 14th fret. I thought it was best to have the finish go underneath the fretboard extention a slight bit... Could a possible solution be to score the finish at the edge of the extention and remove the finish to the edge of the extention at the 14th fret? This would allow the fretboard to be slightly lower at the 14th fret and improve the geometry... that is... keep the fingerboard straight (or straighter) from the nut to the end of the fingerboard.... Any thoughts or suggestions would be appreciated. Steve |
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| Author: | Colin North [ Wed Jul 25, 2012 11:16 am ] |
| Post subject: | Re: Sanding Sides to Ensure Flat Fingerboard... |
I tried Todd Stock's "method", 60 foot radius UTB, rims radiused to 25 feet (I use 25 foot radius for tops) Trim the top of the neck block to project to meet the UTB. Simple, works. |
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| Author: | John Arnold [ Thu Jul 26, 2012 8:51 am ] |
| Post subject: | Re: Sanding Sides to Ensure Flat Fingerboard... |
Quote: An identical body built just after his shows a perfect angle for the extension using a flat surface for the 60' UTB glue-up. I glue the UTB with a curved caul. Works great. I never have measured the radius, but 60' is probably pretty close. The radius on the brace is generated by placing sandpaper on the caul and sanding the brace until it matches. Quote: flat UTB's allow the upper bout to go concave, while a slight radius seems to keep the upper bout from going past flat. Balancing the forces is the key. It is why a violin stays together with such a light structure. There is a lot more downforce on the bridge of a violin than on the fretboard tongue of a guitar.......that is why the violin top needs more arch. |
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