I’ve an old Maplin AA battery charger that although it works well has been dropped a few times and the case got damaged. I don’t really want to use it in that state so I thought I’d take it apart and fix the broken components.
My first issue was that it was held in place by 3 unusual screws. A little bit of research into screw heads showed me that this was a “spanner” type head also known as “snake-eyes” or “notched”. So I bought myself a little set of security bits with these in and brought it home. I then realised that two of the screws were down the end of some deep and thin holes so my bits were useless as they were too wide to fit.
However, now that I had a bit to copy from and low probabilty of finding the appropriate tool very easily I thought I’d try and build my self a driver with this head.
I tool a piece of hex bar and ground the end into a screwdriver blade. I then carefull filed the gap in the middle to match the selected bit.
I looked up tempering temperature and it recommended a blue colour for screwdriver bits so I heated the bar with a butane torch till it got to a cherry red and then quenched it in some water. I then heated it again with the flame aimed below the tip. I did not see the colour blue get to the tip but I stopped before the orange got there and quenched again. This was my first attempt a tempering since I left the Dowty apprentice workshop so I’ll have to practice a bit more.
However, I was luckly that a can opener was being decomissioned this weekend so I grabbed the handle from that. After stripping off the excess components I was left with a simple plastic handle. I heated the end of my screw driver and pushed the handle onto it to melt a lovely hexagon shaped hole.
Finally, I used some white Sugru to hold the handle in place.
Those pesky screws.
Having opened up the charger, I believe it can be fixed but that will have to wait till another weekend. I also found online another security bit project.