Bit for Security Screws on Deuta ENG 8/8 Tachometers

I needed to disassemble a Deuta ENG 8/8 Tachometer used in a steam train for maintenance and cleaning, but the chassis is secured with special slotted security nuts.

This model is a bit that can be used with standard bit holders (e.g. Wera 816R) and allows opening the security nuts.

Disclaimer

Probably it's not a good idea to even open a tachometer, and you might void warranty and calibration. You should probably not tinker with measurement devices that are still in service in railroad equipment unless you really know what you are doing (in which case you probably own a proper tool for this job).

Also, I am not affiliated with Deuta, this is not an official tool for servicing their instruments and you use this part totally at your own risk. Manufacturing the tool requires using an open flame and you might burn yourself if you don't take the necessary precautions. Don't yell at me, you have been warned.

Additional Parts

You will also need 2 pieces of 1mm spring steel wire, each about 1cm long

Assembly instructions

Print with low layer height and organic support. I used the 0.15 structural setting with additional organic support in Prusament PETG.

Grab the Spring steel wire and heat it e.g. with a blowtorch. Insert it into the hole in the front face while still hot. Make sure not to burn yourself and to melt the wire into the part

cut excess wire, but leave 1.5mm wire protruding from the front.

repeat the process with the other wire and the other hole