TOOL INSTRUMENT No256 GPO TOOL, 1933

Unknown device used by the GPO.
The cabinet label reads:- Tool instrument No256 Tester for Tools Instrument
No's 183A and 183B INSTRUCTIONS FOR USE.
1. Place the tool to be tested on the stand with the graduations underneath. 2. Fix the special notched extension lever in the tool with the notches uppermost. 3. For testing the Tool Instrument No 183A, place the small weight in each of the 3 notches in turn and adjust the knurled nut on the tool until balance is obtained. The reading on the Tool for the 3 positions of the weight should be 20, 40 and 60 grammes respectively.
4. For testing the Tool Instrument No 183B use the large weight in a similar manner. The readings on the tool for the 3 positions of the weight should be 70, 130 and 299 grammes respectively. ( See Technical Instruction Tools and Transport (Hand Tools) B. 5101.)

Your comments:

• It reminds me of a "tug tester" for pulling on a wire terminal to ensure it is secure.
  
  Usually when the GPO had two settings on things, one was "go" and the other "no go". I wonder if the heavier weight was supposed to pull the end off, to prove it was not too tight and damaging the ends
  .......... Robert Harvey, Bourne, Lincolnshire, 19th of June 2023
  
  
• It may have been to adjust spring settings. Relays and switching selectors had many springs which had to be adjusted so that they moved between certain tensions e.g at 10gms it shouldn't move, at 20gms it should. The fact that there are 2 weights leads me to believe this. Just an idea. It's about 40 or 50 years before my experience.
  .......... Bob Foudy, Cape Town RSA, 9th of December 2020
  
  
• The markings are GPO standard coding.
  SG means G.Salter
  33 means it was made in 1933
  So 1930s not 1960s
  
  It weighed something as the weights suggest.
  
  .......... Terence Wright, Bow, CREDITON Devon, 6th of March 2018
  
  

A1567