HISTORY:
Sustainability is the name of the game! Anything (that has been tested and still functioning properly) should be repurposed creating saving in wasted Ee and reducing the poisoning our environment when items are buried in the earth at the local tip needlessly.
Never heard of Ee? It is a concept that creates a measurement of ALL things (not just electronics) that humans have made and the energy used in obtaining the raw material, processing the materials right through to a finished product and even should include the shipping of the item to the distributors/retailers.
If you would like to know more about Ee values, please take a look HERE
This rotary switch has been removed from an ancient (1950's) oscilloscope made by Taylor Instruments, UK and in fact the release date of this model 31A scope was 1953
Taylor Instruments were reputed to be a high quality, reliable manufacturer of test equipment, but was purchased by AVO (another VERY famous name) in 1958 and not long after that, Thorn Industries purchased AVO!
This switch (and many other items) has been saved from the 'dustbin of time' ... I have cleaned up the switch contacts, lubed the ball bearing and she is ready to go again!
I am unaware of the switch manufacturer, Lorlin came to mind but this rotary switch predates the formation of Lorlin. Another quality switch maker of the time was Oak Switch Systems but they are a USA manufacturer (famous for their pickup selection switches on electric guitars at the time) and I really don't think a British manufacturer would have imported switches from USA, especially as WWII had only just been finished with.
There are no ID markings found on any part of the switch
I then looked at the other rotary switches from this scope and one switch is marked with some ID but it really doesn't solve the mystery!
It is marked as
AB TYPE H MADE IN ENGLAND
That's all well and fine, you may think "Oh that's Allen Bradley, the USA manufacturer" but I doubt it. Allen Bradley set up their first overseas manufacturing facility in England, 1967. That is well after the manufacture period for the Taylor 31A scope so there appears to have been another "AB" lurking around in Britain at the time!
UNIDENTIFIED MANUFACTURER - Mechanical Rotary Switch
Most likely to have been made in England (Ex Taylor Instruments 31A Scope)
Switch type: 3 position 1 pole
OPEN FRAME
Contacts are break before make
Looks to be Silver plated track and wipers
Extremely 'positive' switching action due to the integral ball bearing
Standard 1/4" Brass nut & base
15mm length round shaft with a SMALL D - much smaller than contemporary D shafts, the attached knob used a grub screw
On the rear there are 4 contact points, one is the common and the remaining three are switch position connection BUT there is also another contact which has NO connection to any other point on the switch - this looks to be something like a "tag strip" sitting on the rear of the switch, just one terminal though.
TESTING:
After cleaning (just cleaned the switch enough to judge the working condition and contact resistance in each position) I DC tested the resistance at each position
My test equipment is not great at such low resistances but I was really looking for either intermittent contact or something a bit "out of the ordinary"
In each position (all were the same) I am reading 0.01 Ohm, moving the shaft a little made no changes to this resistance (stable in other words) to me that is fine for most situations.
When a wiper was not in contact with the track, I had a reading of infinity (50+ Meg which on my gear is close enough to infinity)
COSMETIC CONDITION:
USED
Old (Grandad of rotary switches)
CLEAN
My cleaning was basic, I guess if someone wished to they may continue cleaning the switch in proper solvent - I didn't do this.
I have now placed this switch into a sealed packet ready for a "museum" or to be actually put to use in a restoration project
