I was doing this project 'on the fly', that is, modifying and making as I went along, solving problems as they reared their ugly heads.
So ignoring all the wiggly amp stuff, my man's problems, not mine. I just left the holes where his bits went alone, except for drilling a few necessary holes in the bottom of them so that I could epoxy in a few tophat sections with threads in, just so that I could tighten up any screws that I used.
So the head and neck was done, and the next area to be looked at was where the strings go thru the body.
The next place that the strings hit was the 'Whammy' or tremelo bar. This little piece of metal caused quite a bit of trouble, as it had a taper on the front, and slack screws, allowing it to wobble about. I needed it to be perfectly level and rigidly fixed.
So onto the grinder to have the taper taken off. I then epoxied a bit of brass plate onto where it had been ground.
That plate was then ground level with the rest.
After drilling the thru holes, it clamped solidly to the body.
There were all sorts of screws and plates that fixed onto the whammy bar that turned the strings thru 90 degrees, and kept the strings at the correct height to the frets, so they had to stay, but everything after that was mine, and even at this early stage, I was knocking up rough sketches, to remind me what was needed to keep total control of string tension.
I made a pair of these rollers, one to go on the underside of the whammy bar plate, the other to control the next right angle turn on the back of the body. I kept a standard string pitch from the neck head right thru to the final tensioning block of 10.5mm, and it worked out just right.
It was now time to start making room for my bits. That was done on the mill using razor sharp tungsten milling cutters running at 1200 rpm. I found that gave me a very nice finish on the brown stuff, and which I could easily keep tolerances of 0.002" (0.05mm) so that my metal bits would fit nicely.
A split vice was used to hold the main body, and great care was taken to keep the cutter away from the paper towels used for padding, to prevent damage to the soft brown stuff.
Holes were drilled and tapped using standard metric taps. These were to take the brass inserts that were to be epoxied into the holes.
Just like this.
And they gave a very rigid fixing for the bottom set of rollers.
This shot shows both sets of rollers in position, and the strings, once threaded, have been sent back in the direction they once came.
This bit took a great amount of brainpower to figure out, the strings needed to be held very tight (no slippage), plus the holding block needed to end up at a metal to metal contact point, so that when the strings had their tension released for folding, afterwards, they would be pulled back into exactly the same position and so tension.
The brass clamping blocks were so designed to hold the strings very tight, but without causing damage. On replacing a string, the sliding block is put into a certain position using a setting block, and the string pulled tight before clamping. This worked very well indeed, and required very little tuning afterwards.
As you can see, this lot isn't quite finished.
The finger tensioning screw was made with a 90 degree inclusive taper on the end. This taper fitted into a matching taper in the sliding block. As it is tightened, the sliding block is not only brought into metal to metal contact, but because of the two matching tapers, into exactly the same position every time.
Once again, screwed inserts were used to give a firm anchor point. The two lower ones have yet to be fitted.
This is the finished string tensioner. All that needs to be done is the screw is fully undone and swung up out of the way. That allows the main block to slide backwards towards the rollers, and thus giving enough slack for the neck to be folded.
The reverse operation brings all strings back into nice tension.
The next time, I will be showing how the strings are tuned.
Bogs
