You can sand the top or the bottom of the fretboard to close the gap, no matter what the top radius is.
At 25' you won't have to sand much to close the gap. I use 28' and it works out with no sanding most the time.
| Official Luthiers Forum! http://www.luthiersforum.com/forum/ |
|
| 25' top radius http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=35253 |
Page 1 of 1 |
| Author: | Tai Fu [ Fri Feb 03, 2012 11:31 pm ] |
| Post subject: | 25' top radius |
I made a guitar with 25' top radius (25' top and back to save money on radius dishes) but then the neck angle needed to be rather high as well, resulting in the need for a bridge saddle that are as high as Sears Tower, or giant bridges to compensate. I think 28' isn't that big of a difference from 25' so the question is, do manufacturers who make a top that steep uses a very big bridge as well? Or is it safe for me to use a top that are completely flat with no radius, or will it be safer for me to use a shallow radius (greater than 40')? |
|
| Author: | Colin North [ Sat Feb 04, 2012 5:13 am ] |
| Post subject: | Re: 25' top radius |
?? Not sure I understand. Neck angle is what sets your saddle height, independant of top radius - if it's too high, your neck angle is wrong. You could build with a flat top, or with larger radius if you want to. Some people do either very successfully. |
|
| Author: | Tai Fu [ Sat Feb 04, 2012 5:38 am ] |
| Post subject: | Re: 25' top radius |
Colin North wrote: ?? Not sure I understand. Neck angle is what sets your saddle height, independant of top radius - if it's too high, your neck angle is wrong. You could build with a flat top, or with larger radius if you want to. Some people do either very successfully. What I mean is, the 25' radius forces you to use a very high neck angle, otherwise there would be an ugly gap between the fingerboard extension and the soundboard. How do I have a low neck angle and a 25' radius? |
|
| Author: | Mark Groza [ Sat Feb 04, 2012 8:01 am ] |
| Post subject: | Re: 25' top radius |
You can sand the top or the bottom of the fretboard to close the gap, no matter what the top radius is. At 25' you won't have to sand much to close the gap. I use 28' and it works out with no sanding most the time.
|
|
| Author: | Tai Fu [ Sat Feb 04, 2012 8:18 am ] |
| Post subject: | Re: 25' top radius |
Mark Groza wrote: You can sand the top or the bottom of the fretboard to close the gap, no matter what the top radius is. At 25' you won't have to sand much to close the gap. I use 28' and it works out with no sanding most the time.I'll try that on my demo build, because it already have a 25' top dome. I just see a small gap on a previous build that also has a 25' dome, it's about 1/16" I think but its just enough to make someone think that the guitar was poorly made. I raised the neck angle on that one to close the gap but it ended up making the bridge/saddle height really high. |
|
| Author: | StevenWheeler [ Sat Feb 04, 2012 8:39 am ] |
| Post subject: | Re: 25' top radius |
Tai, A really tall bridge and saddle might cause someone to think your guitar was poorly made as well. Check out tutorials by John Hall, Robbie O'Brian and Hesh. They all have shown ways to acheive proper neck to body geometry. Steve |
|
| Author: | Tai Fu [ Sat Feb 04, 2012 9:02 am ] |
| Post subject: | Re: 25' top radius |
StevenWheeler wrote: Tai, A really tall bridge and saddle might cause someone to think your guitar was poorly made as well. Check out tutorials by John Hall, Robbie O'Brian and Hesh. They all have shown ways to acheive proper neck to body geometry. Steve It never occurred to me that I could shave the bottom of the fretboard to close the gap, I thought of strange solutions like filling the gap with maple wedge, etc. but I just could not find any literature (even looking over Cumpiano's book) on getting everything to look right as far as neck angle is concerned. |
|
| Author: | bluescreek [ Sat Feb 04, 2012 10:06 am ] |
| Post subject: | Re: 25' top radius |
I don't use 25 It does set the neck angle at about 2 degrees. If you radius the entire to a 32 will be about a 1 1/2 degree. Also how you locate the disk will change things. This vid may show you how you can control the disk and its inference to the neck angle http://www.youtube.com/watch?v=LrgRKKsx ... 8CA71FE7D2 I use a 28 dish but don't radius the entire top. Here is another link that a friend of mine uses a 32 and does the entire top. http://www.midatlanticluthiers.org/Meeting_Photos.php |
|
| Author: | Rod True [ Sat Feb 04, 2012 1:37 pm ] |
| Post subject: | 25' top radius |
I make my guitars with a flat top (no dome) but I tapper the body from the top of the soundhole to the top of the body by 0.75*. Basically this is a drop of 1/16" which sets my neck just how I like it. The very best thing to do is draw out the guitar from as many angles as you can. You will get a much better idea of how these things work. Many people use 25' radius dome with great success. BUT it's all about total understanding of the geometry. --- I am here: http://maps.google.com/maps?ll=49.069498,-122.355431 |
|
| Author: | bluescreek [ Sat Feb 04, 2012 2:54 pm ] |
| Post subject: | Re: 25' top radius |
Rod hits a great point , draw it out. As he said drawing this will help you visualize it better. Once you can see it and all the lines are drawn you will see how all the geometry relates to each line. That alone will help answer many questions |
|
| Author: | CharlieT [ Sat Feb 04, 2012 6:32 pm ] |
| Post subject: | Re: 25' top radius |
bluescreek wrote: Rod hits a great point , draw it out. As he said drawing this will help you visualize it better. Once you can see it and all the lines are drawn you will see how all the geometry relates to each line. That alone will help answer many questions When you draw it out, do you draw it to the radius you used for your x-braces, or do you allow for some "spring-back" from the top once the braces are glued to it? Seems like the flat top would counter some of the brace radius, resulting in a final radius that is somewhat larger than what the braces were radiused to. If that's the case, how do you estimate what the final radius will be on the glued up top? Am I overthinking this? 
|
|
| Author: | Rod True [ Sat Feb 04, 2012 7:20 pm ] |
| Post subject: | Re: 25' top radius |
CharlieT wrote: ....Am I overthinking this? Yes. You really can't account for spring back that you can't calculate. Just draw it out as it "should" be and adjust when building. |
|
| Author: | CharlieT [ Sat Feb 04, 2012 7:50 pm ] |
| Post subject: | Re: 25' top radius |
Rod True wrote: CharlieT wrote: ....Am I overthinking this? Yes. You really can't account for spring back that you can't calculate. Just draw it out as it "should" be and adjust when building. Whew! Thanks Rod. 
|
|
| Author: | Trevor Gore [ Sat Feb 04, 2012 8:04 pm ] |
| Post subject: | Re: 25' top radius |
Tai Fu wrote: I thought of strange solutions like filling the gap with maple wedge, etc. but I just could not find any literature (even looking over Cumpiano's book) on getting everything to look right as far as neck angle is concerned. You're not looking hard enough...
|
|
| Author: | CharlieT [ Sun Feb 05, 2012 12:26 pm ] |
| Post subject: | Re: 25' top radius |
bluescreek wrote: I don't use 25 It does set the neck angle at about 2 degrees. If you radius the entire to a 32 will be about a 1 1/2 degree. Also how you locate the disk will change things. This vid may show you how you can control the disk and its inference to the neck angle http://www.youtube.com/watch?v=LrgRKKsx ... 8CA71FE7D2 I use a 28 dish but don't radius the entire top. Here is another link that a friend of mine uses a 32 and does the entire top. http://www.midatlanticluthiers.org/Meeting_Photos.php John - I just watched the top radius video. Lot's of good info there. Thanks for sharing that! |
|
| Author: | Ti-Roux [ Sun Feb 05, 2012 3:17 pm ] |
| Post subject: | Re: 25' top radius |
First of all, if you had draw this before, you would have seen the problem on paper instead of on wood. Second... you have many solution for this (not for this build, but for the next ones) - raised neck - avoid spherical radius I personnaly build with ''compound'' radius. I carved the dome I want on a workboard that have the shape of my guitar. The section where sits the fingerboard is flat, or almost, and the higher point of the dome is under the bridge. Using this method, the ribs stay flat. Works great for me. |
|
| Author: | TonyKarol [ Sun Feb 05, 2012 3:27 pm ] |
| Post subject: | Re: 25' top radius |
I find a 28 ft radius to be perfect .. if you flatten the area where the FB sits, taking off about 4-5 thou will do it, then the FB lies flat there, and shoots back to the bridge area giving about a 1/16 inch gap - perfect fo r a 1/4 inch FB, and a 5/16 to 3/8 bridge and reasonable saddle. |
|
| Author: | CharlieT [ Sun Feb 05, 2012 3:48 pm ] |
| Post subject: | Re: 25' top radius |
TonyKarol wrote: I find a 28 ft radius to be perfect .. if you flatten the area where the FB sits, taking off about 4-5 thou will do it, then the FB lies flat there, and shoots back to the bridge area giving about a 1/16 inch gap - perfect fo r a 1/4 inch FB, and a 5/16 to 3/8 bridge and reasonable saddle. Tony - when you say you flatten the area where the FB sits, are you referring to flattening the spruce top after it is glued to the ribs, or flattening that portion of the ribs before you glue the top to them? |
|
| Page 1 of 1 | All times are UTC - 5 hours |
| Powered by phpBB® Forum Software © phpBB Group http://www.phpbb.com/ |
|