Monday, January 16, 2017

Oh, and more on the truss rod and mounting

Pay attention. More tips on attaching a neck.

Mounting, Truss Rod, and Finishing tips
     Mounting your neck, I have come up with a simple way to mount the neck, you will need,
1.      A reversible drill,
2.      A set of drill bits in 64ths from 1/16th-1/4"(you will be able to assemble your instrument with this set.)
3.      A quick grip clamp with the soft rubber pads. (optional)
4.      A digital caliper (optional)
     To start, fit your neck to the body, with the body lying flat on a table, or other flat surface, support the neck so it lays flat in the neck pocket, with a yard stick, check the alignment of the neck to the bridge, hold your yard stick along the edge of the neck, from the nut down past the bridge, if your bridge mounting screw holes are drilled, you want the yard stick to be equal distance from the edge of the outside two holes. Note the gap in the neck pocket at the upper end, place a shim of the appropriate thickness at that point.
     Now you will pick the guitar up, stand it on the butt of the body, with the neck pointing straight up, place the quick grip in the cutout, holding the neck tight in the pocket, with the handle on the top side of the guitar; check to see if it is aligned with the shim in place, and also that the heel is tight to the body.  Now find a drill bit that just fits the holes in the body, this will be used to drill a center dimple for the mounting hole in the neck, put the drill bit in the reversible drill, make sure it is tight, now, MAKE SURE THE DRILL IS IN REVERSE, insert the drill bit in the holes, one at a time and just hit the trigger lightly, going backwards, this will just drill a small dimple in the center of the mounting holes. When you’re done with all four, remove the drill bit.
     Now you will need the right size drill bit to drill the mounting holes. In rock maple the drill bit should be no smaller than the shank of the screw. With a digital caliper, measure between the threads on your screw, your drill bit should be no smaller then that measurement, but rather, the same size. On softer woods, you can go smaller, but not the hard Maple.
     Put the appropriate size drill bit in the drill, at this time. Put one of the screws along the cutout to see how far into the neck it will go, look to see that it won't go too far, then place the screw alongside the drill bit in the drill, adjust the exposed length of the drill bit so it only sticks out the length of the screw. Tighten the chuck on the drill, and double check that the length is still right. Go through the mounting hole in the body, keeping the drill bit centered in the hole. Drill your mounting holes. You’re now ready to mount your neck. I also use this method to center the holes for the tuners as well.

     The Truss Rod - single action = single rod. What I do is snug up the rod, don't over tighten. Tighten just enough to where the rod doesn't rattle. With light gauge strings and low action, these heavier 50's style necks shouldn't  need much more attention for some time. Before I do a string change, I'll check the relief to see if it needs to be adjusted; if it needs to be, I will snug it up a little when the strings are off. Always adjust the truss rod with the strings off, or way loose. If you do a lot of guitar repairs, you will notice that the guitars that are easy to adjust with the strings on (Gibson – Gretch - Fender bullets), have a lot more problems with broken or stripped adjustment nuts. When the torque to twist the nut becomes greater than to twist the rod, the rod will twist. That's when the trouble starts. If the brass nut doesn't strip, the rod will twist until it snaps; usually at the anchor (Gretch guitars are famous for this). It takes a little bit more time to adjust, tune, de-tune, adjust, tune, check, but done right, you shouldn't need to readjust for quite some time.
When the truss rod slot is machined from the back, the skunk stripe fills in behind it. When you drop the truss rod in from the top then cover it you have no need for it. If you are setup for the one piece neck and want to put a cap on the top you can still come from the back to install the rod. The benefits of the rod from the back is you can have more bow in the rod verses from the top. The cap is 1/4" or less usually and that lowers the available thickness to work with. This I believe is why fender went to the veneered cap in the sixties. The rod from the back is the easiest and fastest way to install the rod. What I like about it is it seems to need less maintenance then the shallower rod,  like the Gibson's. The Gibson rod adjust easier, but uses more tension and is always under tension as compared to the deeper rod and seems to move more in different climates. A friend of mine who works in a large music store in Reno once told me the majority of his setups were from traveling musicians going  from one gig to the next. The thinner the neck, the shallower the truss rod bow.
The way I'm truing the fretboard these days is to first machine the fret board radius, I do this so I don't have to remove a lot more later, then cut the back profile. I then put a slight load on the rod and sand it true using a edge sander setup horizontally, similar to a stroke sander but not a stroke sander. This way I true the F/B to the way the truss rod acts with the neck. After it is trued, I remove it from the fixture, it will have a slight back bow. When I drop the tension back off the rod, I will have between .003-.006" positive bow. I've had "O"  issues with back bow after changing to this arrangement.

 The finish - these necks come standard with two coats of nitrocellulose lacquer,  this will hold up well with moderate usage, You can  apply more, just sand lightly with 320 grit dry.   If your going to use anything other then nitrocellulose lacquer, the original finish should be competently removed. What you don't want to do is wet sand between coats, raw wood will suck it up like a sponge, swelling, cracking , twisting, and all kinds of ugly stuff. I dry sand right up to were I get ready to buff.  I use paint thinner (mineral spirits), on the hard finishes; lacquers - urethane's - and such. Be careful, even mineral spirits will swell up the raw wood. Not nearly as badly as water, but it will swell. Be most careful around end grain; the very back of the neck, front of the peg head, and especially the tuner holes. Why you ask, because the tuner holes are almost all end grain, hard to get enough finish applied to seal it from moisture; any kind of moisture. I tape this area off, and dry sand it after everything else is done. I have a lot less problems that way.

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