Tuesday, April 7, 2009

Finishing up the little stuff.

So at this point the guitars are almost done. Lots of little tasks to take care of to get them set up.
The wiring on these four is very straight forward. I have been amazed at how the sets of pickups, bridge/neck, from ManliusGuitar have such distinctive sounds between them. Getting that neck pickup up nice and high on the body, thus the 21 frets, and the bridge one set back further increases the tonal differences between the two even more. So, for these I decided to keep it simple with just a volume and tone circuit each, with a 3 way selector switch.
Pickup cavities are lined with copper, each piece has a grounding wire. The bridge pickup shield grounding wire extends into the bridge bushing hole to ground the bridge. It is trapped by the bushing upon insertion.
I complete the wiring on a scrap of veneer with holes to match the pickguard.Pickguards get laminated on the underside with copper sheeting and the controls are transfered to it.
Pickup mounting rings get finished with height adjustment screws and springs.All the holes for the rings and pickguards are drilled very carefully with a flagged bit.Screws are dragged across a wax candle prior to driving into hardwood.Salvaged leather, from an old purse, pads the strap buttons.I turn the knobs on a midi lathe leaving a little tenon on each one.Marquetry discs are inlaid and cut to size. Note the blocks for glue up.The holes allow room for the tenon while laminating the caps in place.The tenon is then chucked in the drill press to finish sand the cap flush.I leave the tenon on for polishing as it makes a convenient handle.When they are all done it's safe to remove the tenon and drill the hole for the pot shaft.I make the nuts out of cow bone. I let Heidi's dog, Bea, clean up the bones then allow them to air dry for, well, years. When I first started building these I got a handful of leg bones and they just last forever. The dozuki makes a nice clean cut in bone and I saw the rough blanks by hand.
The blanks are cleaned up and start to take shape on the belt sander.The various grits are sprayed and stuck to a sheet of glass. This give a great polishing surface for finely shaping the nut. It must be a firm press fit in the slot.I leave the top quite high for set up, marking off the 1st fret with a half pencil ala Cumpiano.
The files for resharpening the dozuki are very fine and narrow. I use them to scratch very fine grooves for the string locations. Then I string up, check the string spacing and work the grooves down in a bit. At this point I still have enough room to make substantial lateral adjustments.
Using the 2/0 blade that I prefer for marquetry, I saw straight down for each notch.

The kerf alone is wide enough for the high E string. Various implements are used to widen and polish the notches. Feeler guages are used with sandpaper and for the bottom largest strings I use a specially shaped piece of veneer wrapped with sandpaper to get just the right sized slot.
Once it checks out with just a bit of "nut action"......the excess top material is filed off at a level that lets the base side strings sit down in about half way.
All that's left is to make notches in the saddles,

And polish them out nice and smooth.

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