Repairing an old Mitutoyo profilometer probe

Some time ago I repaired an old Mitutoyo profilometer 178-928D , which no longer has spares and which had broken the pin that transmits motion to the head holder; a calibrated shaft that moves left and right and which I hold in the following image (the pin / screw was in the center hole):

This probe has a very simple operation. The spindle that is coupled detects changes in a very similar way that is translated the marks in an old LP music disk, transmiting the movements caused by the roughness by a magnet and coil needle.

The shaft that moves the spindle is moved in a controlled manner with a step by step motor to an endless spindle, first the engine slowly forward in the measurement phase, and then quickly picking head to its starting position, all controlled from the profilometer which is connected with a cable with 6 wires (that is a seven or eight cable, but one or two are not used, as you can see in the following images after repairing the cable too):

Rehabilitating one Metabo screwdriver with a Li-ion 4400 mAh 12.6V

Metabo BZ 12 SP with DIY Li-Ion Battery

As a gift, I was given an old screwdriver that was going to go to waste. It used the old Ni-MH battery technology or Ni-CD, and you know me ... I love those tools that works wirelessly, so I started to build for it a more economical, durable and powerful li-ion battery than the original, as there are no li-ion batteries for this screwdriver.

Note : Adapting these instructions you will be able to build batteries for any wireless device that you have at home and that, for its price or quality of their batteries, you are considering to throw away.

This requires using Li-ion batteries that allow discharge at 2C at least, or they could be damaged quickly. Lipo could be used but these have half life than other liIon chemistries. The Li-Mn (manganese) allow faster discharging without damage, but are quite expensive, and LiFePo, A123 manufacturer would be ideal, but pricy too.

I found a middle ground in Lico of  Boston Power-shaped like two 18650 united , but actually is a single battery, ovalish format, making better use of the space, and with very good capacity for cases where two batteries are used in parallel (such as laptop batteries), and they have a very good chemistry that is not damaged by 8Ah instantaneous demands such as a screwdriver, retaining its capacity better than others between uses:

See below Load controller chip