I have played about with that... and tried various different versions, none of which were worth recording or making a blog about... so... I decided that it was probably time I tried to make a "decent" single paddle key.
Based on a single lever, using the "springiness" of the lever, I decided to use a simple 3.5 mm brass rod that I had left over from another job... and to use other bits from making the GEMSKEY "designer key"
which, altogether, made it a very low cost key to make.
Here is the process..... bear in mind that I have very limited experience of working with metals, and my "workshop" is not equipped with modern milling and drilling machines !... I only have a bench vice, and a DIY vertical drill stand. a few files, and a couple of hacksaws .
First of all, I decided to make the "contact" pillars. these consisted of two squares of Aluminium, with the corners cut off at 45 degrees.... I needed to do these first, to set the height of the contacts so I could eventually set the rear drill hole heigt to agree with them.. Originally, I was going to "concave" cut the shoulders of these two, but this proved to be more difficult than I anticipated, and ruined one piece of work in the process !! ! ...( Good job I started off with three pieces! ! )..
checking to make sure they are "squared up" to each other after cutting & filing
I decided that it would be a good idea to drill the contact adjuster hole in each one, and then re-profile, if necessary to ensure they were all the same size, by keeping the drill bit in the centre hole during the process. I made a small "jig" to hold the pieces during drilling.
Marking out the corners, and cutting them off, prior to final profile filing, using the drill bit in the centre hole,
Once I was satisfied that they were all the same shape, and "squared up"... I started on the rear support post, which was made from square brass stock...
This needed the central hole for the torsion rod/lever .... a threaded hole in the top for the "lock" screw, and also a threaded hold in the bottom for the securing screw to the base... To prevent it from moving from side to side, during operations. I also drilled two small holes in opposite corners, so that I could fit into them, cut off lengths fo small "panel pin" nails...
Starting the "tap" by hand, proved to be a bit troublesome, on my previous key, so I decided that I would utilise the Pillar Drill stand, and put the tap into the chuck, to ensure it started of vertical and true...
once a couple of threads had been made, I then transferred the workpiece to my bench vice for the remainder of the tapping to be completed..
The next step was to do the tapping of the side contact supports, which I did in the same manner..
Originally I was going to use the "nail pins" to prevent momement, but on completion , this was not necessary, and an advantage of that, is that the surface of the base was only damaged by one hole for the securing bolt to pass through... ( I have in mind, later on, to move the contact support pillars closer to the rear support post... covering the present holes with a couple of brass dome nuts secured from below.)
Once I was satisfied that they were "complete"... I moved on to the "hammer" , on the torsion bar/paddle lever....
My idea was that the "springiness" of the torsion bar, could be adjusted by moving it back or forward... ( short or long reach arm )... giving a variable amount of resistance/springiness.... This necessitated the "hammer" to be adjustable too....
so I drilled a small hole and tapped it, so that I could use a screwdriver to secure the "hammer" in postion after moving the torsion bar shorter or longer.
To ensure that both ends of the "hammer" were "true" and "square".... I put the "hammer" into the drill chuck, and brought it into contact with the bastard file laying flat on the work table.
The finished Torsion Bar Single lever looking good ! !
The finger plate was made from a "re-fashioned" ice scraper for the fridge !... and I use a long wooden dowel with a 3.5 mm hole drilled into it... and a cut out for the plastic "Finger plate" which was araldited together... ( the finger plate dowel was just a "push fit" on to the lever arm ).
The contact points, and their locking screws, were made, using leftover connecting pillars, which gives the key a "professional" look. I really wanted one more, for the rear pillar locking, but ......
So,... now it was time to deal with the base.... this was another "left over" from a previous order I had made for bases.... Being made of MDF, it was easy to work. I marked up the location of the holes, drilled them and placing the base upside down on a foam sponge mad... counter sunk the underneath holes ... Later I "routed" out the routing for the wiring, and drilled a hole in the far end to accomodate the wire with the 3.5mm jack plug on.
Elegant Single Torsion Bar Paddle Key.
Here is the "long arm" version
Here it is in the "short arm" version