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Guitar build – Nut adjustment, cut-away wood removal and sanding

Posted by is9582 on December 21, 2012 with No Commentsas , , , , , , , , ,

When I started playing around on the guitar, after installing the first set of strings, I noticed a couple of things. There was a lot more space between the strings and the fingerboard, at the nut, than on any of my other guitars. Now, I’m not talking about an extra 5 thou or something minute like that. I’m telling you it looked like you could drive a car through the open area. The second is that each string was playing sharp, when held down at the first fret, since there was such a long movement required to get it all the way down. There is a rule-of-thumb that there should be around .005″ between the bottom of the High-E string and the first fret, when fretting the string on the fifth fret.

So I got out a cool little set of wire-files my friend Phil Edwards (Philly Planes) was kind enough to send to me, when I was early in my build. (I wonder, was he in some way implying there was no way I’d get it spot-on, the first time? Haha, just kidding, of course.) I’m so appreciative to have a friend like Phil. The wire-files (about 15 in a little metal container) sizes are just the right range to handle the string thicknesses used on most solid body electrics. I used my digital micrometer to read each string’s thickness, and then do the same with the files, so I had one just a bit larger than the string. I loosened the string and slid it to the side, while I proceeded to remove material from the nut. I did this same process for each string, and I’ve come back to each a couple of times. I’ve got it pretty close right now, as none of the strings play sharp at the first fret, and now barr-chords at the first position are also easy, and sound good. Issues that previously weren’t the case.

After making the guitar play fairly nice, I decided to focus on removing the small wedge of extra wood, in the area of the cut-out, where the neck/fingerboard intersect.

Blue arrow is pointing towards left line, delineating what are to remove.

Since I’d drawn a line earlier, to show which wood was excess, it was easy to use a large paring chisel to slice it away, little by little. I’d decided to leave that extra wood, during the glue up of the neck to the body, just so it would have a bit more strength. I’m sure it wasn’t critical, but it didn’t hurt to show extra precaution, either. Now it looks much better, as well as having better access to the upper register of notes.

Green arrow is pointed towards the area that used to have extra material.

Next up was the back of the guitar. Early in the build, I’d planed the mahogany boards on all sides, before applying the maple cap. This mahogany is somewhat tough to work, as it has reversing grain that is running back and forth, so you’re almost always dealing with some portion of the plane that’s cutting into the grain. As is usual, with this type of wood, there was some small tear-out I needed to deal with. Since the majority of woodworking at that point, was on the front of the body, I decided to just leave that clean-up until the rest of the build was about complete. I turned the guitar over, using some thick towels to cushion the top, so I could take care of the back. I grabbed my Festool Rotex 150, connected to it’s family member, the CT-22 vacuum. This is the first sanding setup I’ve ever used that didn’t belch dust back into the air. It is totally amazing! I started on the back, using 100 grit sanding discs, and in short order, I had a consistently smooth surface. Now, just because I said it was smooth, doesn’t mean I was finished. I actually moved up through the grits until stopping at 320 grit.

Camera didn’t provide a great representation of the surface quality.

Depending on how I hold the guitar, I could see some reflections of my hand/arm in the back’s surface. Oh yeah, I forgot to mention that I had the Rotex set for the rotex rotary mode, to speed along the process. It’s hard to believe the agressive mode can generate a surface that good. I still plan to go back and use the random orbit mode, before moving forward and applying a finish, but it very well might presently be a good enough surface, to obtain a great finish. If you don’t yet own one of the Festool Rotex units, you might want to check it out. They aren’t cheap, but they are so worth what they cost.

Thanks for reading my blog. Please let me know if you have any questions or comments.

Visited a cool local sawmill – Berdoll Sawmill & Furniture Co.

Posted by is9582 on December 20, 2012 with 4 Comments
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Yesterday I took a leisurely drive from Austin TX, out to Cedar Creek TX, to visit Brandon Berdoll at the Berdoll Sawmill & Furniture Co. I was very impressed by the quality of primarily Texas woods Brandon has on hand. The mesquite was truly unbelievable, ranging from 4/4 boards up to 12/4 or 16/4 slabs. He also has some crazy long pecan.

Here I am in front of two amazing pieces of pecan.  (and no, I’m not 24″ tall)

Brandon also has some Texas Walnut, shag oak, white oak, cedar elm … There are a number of huge logs within about 30 – 60 feet radius from the two band saw mills. The larger mill is setup to handle the really large stuff (IIRC I believe he’s had a log in the 20,000 – 30,000 lb range), turning a tree into slabs, while the other can handle the smaller stuff.  He even has a large limb (I know it really is a limb, but it was larger in diameter than some trees I’ve seen) that came from Laguna Gloria in Austin.

I’m standing by what is definitely no larger than a medium log,  for the Berdoll company!

Brandon fabricated what is the largest planer I’ve ever seen. Since he’s only just moved into the new location a little over a month ago, the planer wasn’t re-assembled totally, but seeing the frame and parts, it is huge. To put it into perspective, the planer has four cutter heads, each 25″ long, and below is a picture I took of my daughter by the base frame. They also have a couple of computer controlled kilns, on premises.

My Beautiful daughter, Kortni, in front of the planer frame.
Hard to imagine a planer of this size, for those of us with the 13 1/2″ wide versions.

Give Brandon a call at 512-497-5910, or send him an email at info@berdollsawmill.com, and go get some awesome local hard woods.


Guitar build – Bridge, Pickup selector & Neck attached

Posted by is9582 on December 5, 2012 with No Commentsas , , , , , , , , , ,

First off, let me apologize for the delay between posts, as I was working hard on a deadline. Luckily I kept my nose to the ole’ grind stone, as it was all I could do just to reach a minimal standard. Even so, it was certainly worth the effort. So, on with the blog…

As the build went on, it seemed that more and more of the procedures were such that my heart would miss a beat or two, during the most critical points. It’s really not that the individual processes are truly that difficult, but more that they all must come together as one, so the guitar can do it’s thing. Make music!

The next step was to find the precise placement for the bridge, mark it, and then drill exactly as marked. This is one of those super critical stages that can make or break the guitar. Why you might ask? Well, the bridge serves a couple of rolls. Initially, the bridge sets the scale length of the strings. This is measured from the string contact point of the nut to the saddles of the bridge. If we consider that measurement our vertical, then the horizontal would be aligning the bridge, as a whole, so the strings are centered on the fretboard. Ok, aligned in two planes, that’s doable. Now, one more piece to the puzzle, is to cant the bridge, ever so slightly, so the bass strings are longer than the treble strings. This is necessary as the bass strings intonation is slightly longer length than the treble strings. Luckily, the saddles on the bridge I’m using are adjustable, towards and away from the nut, allowing the exact intonation point to be dialed in. For the non-guitarist, intonation is balancing the frequency of the open string to that of the string when played at the 12th fret (which is one octave up). This prevents the guitar from playing either sharp or flat as you go up the fretboard.

OK, so I marked the layout position of the bridge, by drawing through the circular openings at each end, resulting in circles on the top of the guitar. After finding the center of each circle, I headed over to my drill press. The bushings for the bridge take the same size hole as did those for the tailpiece, so the 7/16″ Forstner bit was the ticket. No, even though I’m sure the chuck is better mated this time, I just didn’t feel the need to add extra anxiety, so the precision twist bit can sit this one out. After pulling the trigger, as they say, I headed back to the bench to see if my drilling was up to standards. I just let the two bushings sit lightly in their respective holes, and the bridge fit beautifully.

Before knocking them down into the guitar, I knew I had to deal with attaching a ground wire, to prevent hum (talking about through the amplifier, when connected) when neither of my hands were touching the strings. I wasn’t certain how I was going to handle this, even though I’d initially thought about finding a way to solder the wire to the bushing. After thinking through all of my options, I decided to let the compression fit of the bushing be my ally. I drilled a small hole (1/8″) from the bridge pickup cavity to the bridge bushing hole on the high E (the smallest string) side of the guitar. I used about 18″ of solid core 20 gauge wire for the ground wire.

Red arrow is hole to going leading to bushing hole.

I stripped away about 1/2″ of insulation from one end of the wire, which I fed through the previously drilled hole.

You can see the bare wire feeding into the bushing hole.

After it was protruding into the bridge hole, I held the insulated portion of the wire while I bent the bare end toward the bottom of the hole. I did this so there would be less chance the bushing might get caught on the wire, pulling it along while the bushing entered the hole. This would possibly cause insulation to block the bare wire from contacting the bushing, and preventing it’s functionality. I used a block of wood on top of the bridge stud, to knock it into place with my dead-blow mallet. Before setting the other bushing, I grabbed my multimeter and tested to make sure the ground wire was properly functioning. Viola! I then repeated the process to seat the other bushing. Before moving on, I decided to find a way to get the just installed ground wire out of the pickup’s way. Using my Dremmel, with a round-end bit, I made a small trench along the wall of the pickup, for the wire to live in.

The ground wire in it’s trench, leading to the control cavity.

Since I used a solid core wire, it stayed in the trench nicely, once it was bent into place. I fed the remaining section of the wire through the wiring channel I’d created before gluing the Maple top to the Mahogany body, and down to the control cavity.

I was getting close on time (only a day and a half away) to my deadline now. I had one more task to perform, prior to being at the stage where I could glue the neck of my guitar, to the body. Early on, I’d drilled out a 1 1/2″ wide hole for the pickup selector switch. I knew this had to come before the neck, as I’d have a tough time accessing this area, with my current drill press location. Using a digital micrometer, I checked to see if the length of the threads on the selector switch would reach through the top. As expected, the top was too thick to just drill the hole the selector feeds through. I had to drill a hole large enough for the mating shoulder, behind the threads, to get closer to the surface first. I did the drilling in this order, since my centering point would be obliterated if I first drilled the through-hole. After drilling and removing material so the shoulder would be closer to the top surface, I changed to a smaller bit, but left everything clamped in place so I would hit the same centering point. Success! Well, pretty much a success. Since the top of the guitar is sloping in the area of the selector, the wedged shaped wood I placed under the top, didn’t totally prevent some tear-out (seen in photo of neck glue up below). Luckily, the selector switch has a large circular plastic guard that fits around it, so this will be hidden from view. Still a success in my mind.

Now it was time for the pieces to come together as a guitar. It was time to glue the neck/fingerboard combo to the body. I tested the fit and placement of the neck over and over on this build, so I’d be sure no issues could jump up and bite me. Even with all of that, something reared it’s head. I’ll explain. I applied a thin layer of yellow glue to the mating parts, having all the necessary clamps at hand, and pressed the tenon home into the mortise of the guitar. After moving it slightly, it seated beautifully. I applied my two long-reach luthier’s wooden clamps to the fingerboard area, since they have cork pads, and they would do no damage to that area. I saw a thin line of glue all around the fingerboard, indicating the parts were mating properly. While looking at the clamps, I felt the exposed tenon, in the neck pickup cavity also needed some pressure, to adhere strongly. I used a heavy duty F-style clamp in this position, along with cauls to prevent marring.

Two cam clamps with one beast of an F-clamp (red).

Shot a bit more from above.

Better angle of clamps, and close up, to see the caul I used in the pickup cavity.

Everything looked good (lighting is critical, remember this), so I went in from the shop to let the glue do it’s thing. Well, I came back out after a couple of hours and this is when my heart fell. When I changed the guitar’s position, I could see the front most portion of the tenon had lifted slightly (1/128″ – 1/64″), along with the fingerboard and the heel.

Gap between the heel and the body is hard to see, but when you build something,
you know it’s there.

It seems that when I was testing the fit of the mortise/tenon, that I hadn’t realized there was a very small gap below the tenon, at the very end. When I applied pressure to the heavy-duty clamp, it was more than the initial clamps could stand. I went through the possibilities quickly, whether I might still be able to reverse the glue, but came to the conclusion this would likely tear that section apart, and could not be rectified. I decided to let it stay and cure, and I’d string it up and test it out. There was still a great deal of long-grain to long-grain contact, so it would be an experiment of sorts.

I was surprised, after the first string-up, that the guitar still sounded good and didn’t have any noticeable sound issues (lack of sustain) that I’d initially imagined might come with the issue. The main reason for this full disclosure, is for my readership. So, while I would prefer the glue-up had occurred perfect as practiced, it is yet another learning tool for my arsenal, and I hope your’s, too. I’m still proud of my first guitar and will write additional articles as I install the electronics and apply the finish.

Oh yeah, the deadline, it was the recent Austin TX Lie-Nielsen Hand Tool Event. You can check out a few photos of me, showing my guitar to customers, on their Facebook page.

Please let me know if you have any questions or comments.