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Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment |
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11th Nov 2018, 9:50 pm | #1 |
Retired Dormant Member
Join Date: May 2016
Location: London, UK.
Posts: 6
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56C ringer.
Hi.
I have a 56C ringer, of the two screws that connect the power, one has vanished. On the assumption that it does not magically reappear, does anyone know the thread? It seems to be an imperial thread somewhere roughly equivalent to M4. |
14th Nov 2018, 11:20 am | #2 |
Retired Dormant Member
Join Date: Oct 2018
Location: Northampton, Northamptonshire, UK.
Posts: 10
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Re: 56C ringer.
It might be a 3BA which is 4.1mm o/d or a 4BA which is 3.6mm o/d. If it's 3.6mm o/d you should be able to tap out to M4 or if it's 4.1mm o/d you might be able to tap out to M5 if it comes to it.
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14th Nov 2018, 11:47 am | #3 |
Dekatron
Join Date: Feb 2005
Location: West Cumbria (CA13), UK
Posts: 6,118
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Re: 56C ringer.
More likely to be 3BA, as the GPO tended to use odd-numbered BA threads.
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Mending is better than Ending (cf Brave New World by Aldous Huxley) |
16th Nov 2018, 11:51 pm | #4 |
Retired Dormant Member
Join Date: May 2016
Location: London, UK.
Posts: 6
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Re: 56C ringer.
Thanks - I've ordered £3.00 worth of 3BA from ebay - I'll confirm on here if they fit!
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