Archive for October, 2008
Those of you with a long memory may remember my noble endeavor to convert a drill stand into a fretpress. Turns out, it was a bit punky, and the wheels came off.
Actually, the lever came off. It didn’t have any wheels.
Anyhow, let me present the replacement, this time converted from an el cheapo Screw Fix welding clamp.
To convert it from the original use as a welding clamp, I drilled out the rivets holding the lower jaw, and bolted in a straight replacement, using M6 nylox nuts and a section of .25″ steel cut from a discarded hydraulic door closer arm. The top jaw was cut short, and rounded over at the end.
I fitted a pivoting glass-filled nylon fitting to the top jaw, to hold some fretting cauls from Stew Mac, and a teak neck caul (padded with leather) on the lower jaw, slotted to slide back and forwards to allow self alignment as the adjustment of the jaws changes to suit different neck sizes. The pin to prevent the neck caul falling off is an offcut of M6 studding.
Here it is in situ:
The neck shown is the first one I fretted with the new gizmo, and it went very smoothly, despite the complications of an ebony board and teeny-tiny Fender style frets. It’s a replacement neck for Tim’s Musima, more details to follow…
P.S: The flat clamp included in the screwfix welding clamp set is very handy for holding nuts, saddles and other small parts for shaping on a belt or disc sander, especially if you share my aversion for sanding away the tips of your fingers.
Here’s a classic example of why I go to so much trouble to construct a scarfed, back strapped headstock. The owner of this Gibson Les Paul Standard wasn’t aware of having broken the neck - he opened the case and found it broken. Most likely, the case tipped or fell a short distance, and was stopped abruptly by hitting something. The weight of the tuners, supported at the end of the neck, combined with the Gibson Les Paul’s 1 piece neck (which results in very unfavourable grain orientation in the headstock area) and large trussrod adjustment cavity, allowed the whiplash effect to crack the headstock cleanly away from the neck.
From the side you can see that the only thing holding this all together is the plastic headplate, which is flexible enough to act like a hinge:
A (badly focused!) close up shows how little wood is left in the neck once the trussrod cavity is cut - you can see righ through the headstock!
The good news is; as easy as these breaks are to produce, they’re also pretty easy to fix. The headplate holds everything in alignment, and there is plenty of surface area for a good glue joint, which will be as strong as the headstock was originally.
To clamp the break closed, I use a spanish windlass setup. I run a piece of electrical cable (strong, with a cushioned surface, but not very stretchy) through the tuner holes in the head and around the lower strap button, then add tension by twisting a piece of scrap timber in the loop. Once it’s tight, I extend the scrap out to one side, where the neck prevents it untwisting.
This setup only works if the head veneer is intact, but is a very easy way of closing up the fine feather-edge of the break. It also allows easy access to all sides of the repair to clean up glue squeeze out. With the squeeze out wiped away with a damp cloth, I add an f-clamp (with a flat clamping caul and leather pad) to apply extra pressure of the rest of the break.
After for 24 hours, I unclamp the break, and carefully level the repair. Very little levelling is required, and the result afterwards is pretty clean.
However, it can be improved. Gibson still use nitro lacquer on their guitars, so this is what I use for touch up. I apply generous drops of laquer with the tip of a brush to fill any missing chips of finish, then sparingly brush over the entire area.
This lacquer needs time to cure, at least 1 week, or prefferably longer. Once it’s dry, it’s relevelled, wet sanded to 1200 grit and buffed to a shine.
Not a bad result if I do say so myself!
P.S: The guitar didn’t actually keep changing colour - that’s my photography and image editting!