Garrard Super Motor. Reinventing the wheel............

[anchorman]

I bought the appropriately sized stainless steel spring steel from my favorite industrial supply house, McMaster-Carr.

Then I heated the end to anneal it and make it easier to bend. You have to be careful not to do too much, it’s an all or nothing situation. Once you anneal this particular stainless steel, there is no hardening it through heat treatment. It is only hardenable to spring temper by work hardening.

I decided a keyhole would be superior to a pear shaped hole, so made a jig out of steel to support the softened spring steel while I drilled and milled it. I made note of the distance of the hole from one corner of the jig, so that I could consistently set it up in my milling vice. Big hole was drilled, then I used a 3/16” end mill to elongate the keyhole. Worked beautifully and consistently, with very little cleanup needed. Finally, the ends of the spring are ground to give a radius to make it easier to get them into the spring barrel. It may be entirely possible to skip annealing on the outer end of the spring, but it does make it more difficult to get the spring to latch onto the barrel.

The springs seemed to work great. I made on for an HMV 101/102 to start with, since the thickness and width are close enough to the same as for the garrard super, and once I confirmed that it worked, I measured off appropriate lengths for the two garrard super springs. Stainless steel (I can’t remember the exact alloy, but will look if anyone is interested), is supposed to have better life, and less tendency to take a set and get “tired” than the standard carbon steels, I also don’t have to worry about the pitting. The price was not much more than carbon steel spring steel, and given that the bulk of the cost was my labour, well worth it to me. I would have liked to use the elgiloly, or some other exotic alloy, but it was not possible to source a small quantity of that at a cost I could justify.

As an aside, I’m pretty sure that I “reverse wound” these springs, opposite the set that they had from the mill. This is a technique used especially in watch and clock mainsprings in order to help even out the spring’s force over the course of it unwinding, and give more even torque to the motor.

I hope that others can see that this isn’t a terribly daunting task, and could be done successfully even without a knee mill. A simply drill press and a jeweler’s saw and some files could easily be used to make the hole. You do need a way to bend the crimp at the inside and, but a good vice can be used for this task once the spring is annealed. If you don’t have an acetylene torch to heat the end quickly, it would probably be wise to pack the length of spring immediately adjacent to where you heard heating with clay in order to stop the heat migrating beyond where you want to soften. An ordinary plumbers torch and a small propane cylinder could probably heat the end hot enough to anneal, though you may need to use a couple piece of soft firebrick to help contain the heat in that case.