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| Possible truss rod/UTB problem- LMI Kit http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10101&t=17717 |
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| Author: | Jeremy Douglas [ Mon Jun 23, 2008 9:43 pm ] |
| Post subject: | Possible truss rod/UTB problem- LMI Kit |
On the DVD Robbie says he drills the hole to 3/8" diameter and uses a larger UTB. I decided to go with a 3/8" x 5/8" UTB but once I drilled the hole I thought there might be a problem. The hole looks awfully big for that brace. Here are some pics:   You'll notice the hole is quite a bit bigger than the rod(1/4"). Robbie says this makes it easier to adjust. So is this ok as is or should I make a bigger brace or possibly make a brace the same size but with a smaller access hole? Thanks, Jeremy. |
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| Author: | Heath Blair [ Mon Jun 23, 2008 11:33 pm ] |
| Post subject: | Re: Possible truss rod/UTB problem- LMI Kit |
some others with more experience will chime in here, but i think you are fine. it looks like there is plenty of meat above the hole and the other side will be glued to the soundboard. i dont think there is any appreciable strength lost here. will you be radiusing the brace or glueing it flat? if you are radiusing and have not done so yet, just make sure you dont remove too much material from the glueing surface and open up that hole. besides, if robby said its ok, then you should be good to go, right? |
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| Author: | Jeremy Douglas [ Mon Jun 23, 2008 11:45 pm ] |
| Post subject: | Re: Possible truss rod/UTB problem- LMI Kit |
hblair wrote: will you be radiusing the brace or glueing it flat? besides, if robby said its ok, then you should be good to go, right? Thanks, I radiused only the edges of the brace so it will be flat under the fretboard. I trust Robbie but he says he uses a larger UTB and mine is definitely smaller than his; otherwise I wouldn't have even thought to ask. |
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| Author: | j.Brown [ Tue Jun 24, 2008 12:01 am ] |
| Post subject: | Re: Possible truss rod/UTB problem- LMI Kit |
I believe he starts his hole center further down than you have yours... |
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| Author: | j.Brown [ Tue Jun 24, 2008 12:24 am ] |
| Post subject: | Re: Possible truss rod/UTB problem- LMI Kit |
Scratch that...now that I look at it again, I take it back. It looks like you've got 2mm or so. You should be ok, you've just got a shorter UT brace than Robbie uses in his video. -j. |
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| Author: | David Collins [ Tue Jun 24, 2008 12:42 am ] |
| Post subject: | Re: Possible truss rod/UTB problem- LMI Kit |
Keep in mind that that immediate area will be heavily heavily reinforced with a massive ebony or rosewood brace above the soundboard. Some people call it a fingerboard, but it's really a brace, just like the sides and bridge. 
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| Author: | Jeremy Douglas [ Tue Jun 24, 2008 1:06 am ] |
| Post subject: | Re: Possible truss rod/UTB problem- LMI Kit |
David Collins wrote: Keep in mind that that immediate area will be heavily heavily reinforced with a massive ebony or rosewood brace above the soundboard. Some people call it a fingerboard, but it's really a brace, just like the sides and bridge. yeh, but it is also pushing against the UTB so I wasn't sure how everything tied together. |
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| Author: | Jeff Highland [ Tue Jun 24, 2008 5:16 am ] |
| Post subject: | Re: Possible truss rod/UTB problem- LMI Kit |
You could just cap the brace with a spruce offcut say 1/8" thick 2 1/2" long |
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| Author: | Hesh [ Tue Jun 24, 2008 6:19 am ] |
| Post subject: | Re: Possible truss rod/UTB problem- LMI Kit |
I don't drill a hole in my UTB and make the guitar owner or player learn at the most inopportune time that they will have to purchase a special, right angle, allen wrench from me for a price of $3,200.00 US.  Of course this drives guys like David Collins nuts and he turns into Darth David..... Seriously Jeremy the hole looks big to me too for that size of a brace and I would and do use a smaller hole. I agree with all the arguments reminding us that we have a fingerboard extension over this area but I like my holes as small as possible but still large enough pre-tested to ensure an easy and accurate alignment with the truss rod using a standard tool. I will say though that with a larger hole your guitar will be lighter in weight....
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| Author: | Dave Anderson [ Tue Jun 24, 2008 7:30 am ] |
| Post subject: | Re: Possible truss rod/UTB problem- LMI Kit |
You will be fine with the huge fbb (fingerboard brace) above the area as David said. But the hole does LOOK kinda big. I like the hole just a little larger than the rod end and thats plenty of room for a wrench to fit. |
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| Author: | Robbie O'Brien [ Tue Jun 24, 2008 8:33 am ] |
| Post subject: | Re: Possible truss rod/UTB problem- LMI Kit |
Jeremy, My upper transvers brace is a bit beefier than most. I can therefore get away with a 3/8 inch hole with no problem. To me, that brace is argueably one of the most important on the guitar. However, I have gone to a 5/16th hole since making the dvd. |
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| Author: | David Collins [ Tue Jun 24, 2008 8:40 am ] |
| Post subject: | Re: Possible truss rod/UTB problem- LMI Kit |
jeremy3220 wrote: David Collins wrote: Keep in mind that that immediate area will be heavily heavily reinforced with a massive ebony or rosewood brace above the soundboard. Some people call it a fingerboard, but it's really a brace, just like the sides and bridge. yeh, but it is also pushing against the UTB so I wasn't sure how everything tied together. Yes, it does put some stresses on the top, but that's why I chose the words "immediate area". About an inch each side of the board is so strongly reinforced by the thick rosewood / ebony cap, that any significant load is transferred out to the edges. If you imagine the top or brace distorting or failing directly at or around that hole, try to picture how much the fingerboard would have to distort or shear for that to happen. The load is transferred to the edges, but the immediate area around the hole is very heavily capped and reinforced. You may occasionally see slight cupping of the area an fingerboard in heavily warped tops, but even then the cupping will be found smooth and spread evenly across the width of the board. You'll never find a sharp kink of failure or distortion at the access hole. It's just as likely to find on a headstock adjustable guitar as one with drilled brace access though, and flexing of the area is more often due to a dried out top and fingerboard. In my years of repair, I don't believe I've ever seen a failure or distortion that I thought could be attributed to the access hole. I see the solid brace as more of an aesthetic (and I'll admit it's a nice one at that). That being said, that hole does look a bit big, and I would personally probably replace the brace just to keep it from looking crude. |
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| Author: | Terence Kennedy [ Tue Jun 24, 2008 9:12 am ] |
| Post subject: | Re: Possible truss rod/UTB problem- LMI Kit |
I've always used a 3/8" hole close to the base of the brace and have not had problems to date with 26 instruments. My brace is 5/8" high and 1/2" wide. I don't think it's too big an issue. (Isn't 3/8 the size Martin uses?) 5/16 actually sounds like a good idea though, I'm going to give it a try on my current builds. Terry |
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| Author: | Jeremy Douglas [ Tue Jun 24, 2008 10:08 am ] |
| Post subject: | Re: Possible truss rod/UTB problem- LMI Kit |
Thanks for the help everyone. I think I'm going to make another brace with the 5/16" hole like Robbie said and also try to make it more accurate this time. I don't have a drill press and the only bit I had in 3/8" was a spade bit so I ended up with a slightly larger and less round hole  I think I'll go buy a 5/16" brad point. If anything it will at least look better.Thanks again Jeremy |
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