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  #31  
Old 02-18-2012, 07:52 AM
Randy Muth Randy Muth is offline
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Thanks Laurent, I really enjoyed talking with you at Woodstock. And thank you John.

Robert, good question. These are tone bars in the truest sense of the word. They have no affect on the structural integrity of the top. In fact they don't raise the lower resonance frequencies of the top either. The open areas in the lower bout are quite large and there can be quite a bit of flexing there. Once I glue these braces on they sort of "tie" things together and it flexes more as a unit. I'm not looking to really stiffen up the lower bout per say, but I don't like to see a relatively small area move a lot when I press down on it. My gut feeling is they help out with the midrange response of the guitar. Because the bridge is so much lower in the lower bout on 12-fret guitar, I don't need them there. I did build a small body (S14) 14-fret guitar without them and I felt that the midrange was lacking relative to the guitars I build with them. Not a lot of data to go on, more intuition.

Regarding tuning, I mentioned that I tap, scratch,flex, deflect, and sonicate. No one thing I do in handling the soundboard is my master. It is a very holistic approach for me. Usually after I get things where I think I want them, I will put the soundboard down for a day and then come back to it and handle it a while more and do some minor tuning. Morning is best when there is a certain stillness in myself. Often this "minor" tuning will take a soundboard that sounds very good and make it come "alive". It is really a very intimate process for me and is the most satisfying part of building. This intimacy is a luxury that can't be afforded in a factory setting. Because every piece of wood and every soundboard is unique, I really feel like it is a living thing. This may seem like an odd thing to say, but I am very good with animals. I have always been able to quickly develop a sense of how they like to be touched and treated and they take to me very quickly. It really is just about being aware and open. I'm starting to feel the same way abut soundboards. Pretty esoteric for a scientist, ehh!

Time to leave for my daughter's Odyssey of the Mind competition.
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  #32  
Old 02-19-2012, 11:17 AM
Randy Muth Randy Muth is offline
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Here's a photo of the finished soundboard being glued to the top. These clamps are made from bed springs. They are very quick and easy, and provide nice even pressure around the rim. I learned this trick from David Hurd who I believe got it from Bob Gleason. One question I had was whether there was enough clamping pressure. So I tested it of course. The wood breaks before the glue joint no matter how hard I try.

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  #33  
Old 02-19-2012, 11:24 AM
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Randy - those clamps look great! Can you please explain the pads on the eds and how you attached them?
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  #34  
Old 02-20-2012, 01:05 PM
Randy Muth Randy Muth is offline
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CET - The wire is from the large ring of the coils in a box spring. Found one on the curb someone was throwing away, grabbed it and had way more than I needed. Just cut them with heavy duty cutters. The ends are cut from a 5/8" wooden dowel, about 1.5" long. Just drill the appropriate size hole in them and stick the end of the wire in. I then dipped them in Plasti-dip a couple of times. That's the stuff they sell to dip tool handles in and such.
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  #35  
Old 02-20-2012, 05:14 PM
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Love the clamps I don't remember seeing them before ... won't my duaghter be surprised when she comes home (from college) to find her box spring missing and her matress on the floor

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...

Regarding tuning, I mentioned that I tap, scratch,flex, deflect, and sonicate. No one thing I do in handling the soundboard is my master. It is a very holistic approach for me. Usually after I get things where I think I want them, I will put the soundboard down for a day and then come back to it and handle it a while more and do some minor tuning. Morning is best when there is a certain stillness in myself. Often this "minor" tuning will take a soundboard that sounds very good and make it come "alive". It is really a very intimate process for me and is the most satisfying part of building. This intimacy is a luxury that can't be afforded in a factory setting. Because every piece of wood and every soundboard is unique, I really feel like it is a living thing. This may seem like an odd thing to say, but I am very good with animals. I have always been able to quickly develop a sense of how they like to be touched and treated and they take to me very quickly. It really is just about being aware and open. I'm starting to feel the same way abut soundboards. Pretty esoteric for a scientist, ehh!

...
I really like this description ... it is the thing I love about this craft, the mixture of science, art, technology, craftmanship combining to create an aura, a soul to the instument ... it is really cool The idea of putting the soundboard down for a while, I do that too ... as a matter of fact I was finishing up a soundboard late last week, and came back to it this morning, a couple of "tweeks" and it got glued to the rim (the sides) today. I do attach my tops first, so it may even get some more adjustment tomorrow before the back goes on.

Good work Randy ... looking great.
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  #36  
Old 02-20-2012, 05:43 PM
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CET - The wire is from the large ring of the coils in a box spring. Found one on the curb someone was throwing away, grabbed it and had way more than I needed. Just cut them with heavy duty cutters. The ends are cut from a 5/8" wooden dowel, about 1.5" long. Just drill the appropriate size hole in them and stick the end of the wire in. I then dipped them in Plasti-dip a couple of times. That's the stuff they sell to dip tool handles in and such.
Randy - thanks very much for that information. I'm going to have to give those a try.
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  #37  
Old 02-20-2012, 06:32 PM
Randy Muth Randy Muth is offline
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CET - Note that I use fish glue to glue the plates on. Fish glue and hide glue tend to draw the joint together as it dries. Aliphatic resin glues such as Titebond may need more clamping pressure. I always test my joints for each glue and technique that I use.
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  #38  
Old 02-20-2012, 07:03 PM
Randy Muth Randy Muth is offline
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Here are some more photos. Here is the soundboard glued to the rim.



Here are a bunch of pictures showing progress on the neck. I insert a 5/8" hard maple dowel in the heel and use a bolt-on joint. These dowels are not the kind you buy in the local hardware store. This helps to reduce heel flex and provides more bite for the inserts.



The excess meat is now removed on the bandsaw and then the back side is tapered more accurately using a safety planer on the drill press. Notice the tapered carrier board underneath the neck. The truss rod slot is used a lot for indexing the neck.





I now rough profile the side of the heel using the table saw. As far as know this technique originated with Charles Fox.



The sides of the neck blank are now tapered using a flush trim sled on the table saw. The taper is the same as the final taper but an 1/8" of excess is left on each side. You can see why I haven't glued the headstock on yet.



Here is a shot of the neck blank ready for gluing the V-joint. My fingerboards are independently supported. Two slots have been routed into the neck and two rails have been glued in. After the headstock is glued on, slots will be cut from the ends of the rails all the way into the headstock to receive carbon fiber rods. The carbon fiber rods follow the taper of the neck. The taper of the neck blank is used to guide the routing of the slots and will also be used to guide the cutting of the carbon fiber slots on the table saw. Life is a lot easier when things are done in the right order.



Here I am finally gluing the headstock on. It's a number of steps just to build my neck blanks, but they go quickly and they are certainly worth it.

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Old 02-21-2012, 04:26 PM
Randy Muth Randy Muth is offline
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Here I am cutting the slots for the CF rods on the table saw. Notice the spacer since the headstock is on now.



Here I am using the radius bowl to scribe the profile on the side. The bowl rests on three points; there is a threaded rod as the third point coming up through the soundhole that can be adjusted to give the correct incline.



Here I am using a chisel to profile the side to the line. I will finish up with a block plane. Here is where I get to test my side reinforcement strips.



Linings Part 2.

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  #40  
Old 02-23-2012, 04:06 PM
Randy Muth Randy Muth is offline
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The back has been thicknessed and sanded; here I am gluing the back strip and bracing on. Tomorrow I will tune the back bracing and close the box. More on the neck too.



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  #41  
Old 02-24-2012, 05:07 PM
murrmac123 murrmac123 is offline
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]
Randy, it's difficult to tell from the pic, but am I correct in thinking that these are brass threaded inserts ?
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  #42  
Old 02-24-2012, 05:25 PM
Randy Muth Randy Muth is offline
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Yes they are brass. These are from Woodcraft. I've tried about 5 different types of threaded inserts and have found that these work the best for me.
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  #43  
Old 02-24-2012, 05:36 PM
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Quote:
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Yes they are brass. These are from Woodcraft. I've tried about 5 different types of threaded inserts and have found that these work the best for me.
Randy, the build is looking great. I may "borrow" some processes from you ... thanks.

There was an article a while back in either the GAL or ASIA journal (but I can't put my finger on it at the moment,) that evaluated the inserts under some different testing. I don't quite remember which ones worked out (best) in his tests, but it would be interesting to find out if they were same ones you use. It doesn't really matter ... as like you said those "work the best for you."
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  #44  
Old 02-24-2012, 06:25 PM
Randy Muth Randy Muth is offline
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Hi John, yes the article was in American Lutherie, Spring 2010 (#101). The outcome was that a very fine machine threaded insert was best, which was quite contrary to the idea of using the coarse steel threaded inserts commonly used and sold by McFeeley's.

I tried both of those but didn't like either of them. So much depends on the wood, grain orientation and how well they are installed. In fact ease of installation is a factor. I will point out that the article stated that they are all strong enough if installed correctly. What I did like about the ones recommended in the article is that the threads are fairly close together, however they were very shallow and didn't bite very deep into the wood. The ones I use are also fairly close together, but are a little deeper and sharper. In my case the inserts go into the hard maple dowel that I have in the neck (not end grain), so finer threads work well. I should point out that in the article the inserts were tested in mahogany end grain and the fine threads still came out on top, but I don't know.

I was going to post some more pics, but I decided to call it quits for the day.
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  #45  
Old 02-24-2012, 06:32 PM
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I hadn't looked in for a couple of weeks. Randy, you seem like such a regular guy in person, and here it turns out you are genuinely eccentric. Very impressive concept and execution!
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