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Old 28th Apr 2019, 11:32 am   #11
Pellseinydd
Heptode
 
Join Date: Jul 2007
Location: Flintshire, UK.
Posts: 707
Default Re: When was the No 12 dial introduced?

The 'N' diagram for both trigger dials - the 'Dial Auto No 12' and the 'Dial Auto No 13' (coinbox version) - are both dated 11th May 1944 .

However the 'Vocabulary of Engineering Stores' Section 14 (which includes the list of dials in use) dated 1st of June 1944 doesn't list the No 12 or 13.

The N diagram for the Tele 332 was still showing it as being fitted with a Dial No 10 until the issue dated April 1974 which shows it being fitted with a Dial No 21.

The Bakelite 3XX wall series (introduced c.1950) seem to have had No 12 dials fitted from introduction as does the Tele 312 (introduced late 1949) and the later Tele 314.

However over the years as the Bakelite telephones went through local 'wipe-up' depots or back through PO Factories the No 10 dials would likely have been swapped for No 12's.

Looking at the adverts in the IPOEE Journals from 1944 onwards would be likely to show when the trigger dial was fitted to the Bakelite telephones.

Ian J
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