Stage Two Knob cracking

 
As I said earlier in this project the tooling and construction is bare minimum so drilling and tapping screw threads for fixings etc is out, same goes for knurling adjusters and the like but this does cause problems, a typical instance is the next stage as you know we are using sleeve bearings this means there must be some way of keeping the axle central and holding the key handle in place, so let me introduce you to the gentle art of knob cracking! sounds painful but great fun as there is an element of surprise involved, nearly all 1/4 shaft radio knobs have metal inserts built into the manufacture this is so the knob is durable and can be tapped to include a grub screw which is used to tighten the knob onto the control shaft these are usually nicely knurled and very useful in key making as they can be used as adjusters and various other jobs. The knob is held in a vice and a slot cut in the plastic on both sides with a hacksaw then inserting a screwdriver into the slot the metal insert is prised out, some typical ones are seen below, the older they are the more brass there seems to be
And as they are 1/4 inch they fit nicely into the pivot axle, sometimes they have to be drilled through and sometimes cut to length so some ingenuity is required here, above bottom right you can see them fitted to the pivot, the two outer ones are to keep the axle central and are adjusted so they just rest against the side plates, the central one will be soldered to the key arm this means the whole assembly can come to pieces in seconds, this is a real requirement for homebrew keys as during  construction the key will have to be assembled and disassembled many times, the centre one needs to have the grub screw to one end and at least 1/4 inch of  spare brass to solder the arm to, this shouldn't be a problem as most old knob inserts meet this requirement, Below is a slight change of plan, you can see the axle has been extended and two inserts have been fitted to the outside of the bearing, on the inside two more inserts are sweated onto the handle, there are loads of ways of doing this as long as the handle is central and the axle centred, all depends on what inserts are found and where they can be best fitted, I have also rounded off the corners of the pivot sides plates to make them more pleasing to the eye