East German Watchmaker's Drill press

Drill press overview

I got this old and interesting east German drill press. It was in working condition but I decided to service it a little in order to make it last longer and do some preventative maintenance. What’s really interesting is that this drill press uses a Centrifugal governor for speed regulation.

Work piece Table

The most interesting thing is, that contrary to other drill presses, where you have a pinole that lowers the drill this drill possesses a table that raises the work piece to the spindle.

I disassembled the parts, cleaned the grease off them and polished them with scouring pads.

disassembled parts cleaned parts reassembled
broken screw

One of the screws was bent, unfortunately I didn't had any DIN84 M4 screws around, so I used a DIN912 M4 screw instead for now. I'm going to order a proper replacement on my next collective order.


Motor plate

The motor plate specifies the motor as follows:

VEB Elektromotorenwerk  Hartha
E Mdt   Typ FM87/60
H  Nr.  59/97528
4000 U/min 50 Hz
220~ V 0,7 A 70 W
   cos  uF 6563

4000RPM is quite a lot for a motor running off 230V/50Hz. The bearings still looked okay, so I just applied new PTFE grease to them. The motor switch was slightly oxidated and corroded. The carbon brushes also looked fine.

Motor in service Motor bearing Motor switch

Motor capacitor

The original paper foil motor capacitor (from Frolyt) was already leaking and and didn’t make the best impression so I removed it. It is a dual capacitor, with a 0,1μF and a 0,005μF commoned together on one side. The 0,1μF is the actual motor run capacitor and the 0,005μF was phase to protective earth.

What surprised me the most was that the run capacitor is only 0,1μF, that is quite small for a single phase AC motor like this.

I replaced the run capacitor with a foil capacitor, I have not yet replaced the suppression capacitor to protective earth, as this requires a Y class capacitor which I don’t have at home right now.

old Frolyt motor capacitor new capacitor new capacitor

Centrifugal governor

Centrifugal governor