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| Other Vintage Household Electrical or Electromechanical Items For discussions about other vintage (over 25 years old) electrical and electromechanical household items. See the sticky thread for details. |
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10th Mar 2024, 4:20 pm
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Nonode
Join Date: Dec 2012
Location: Stockport, Greater Manchester, UK.
Posts: 2,122
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Screw threads in Bridges drill?
Did Bridges make their own screws for their products? I'm throwing out this fine example and decided to retrieve the screws, assuming they must be something useful like 4BA or 3/16BSW but I can't identify them. They don't seem to be of any use unless you are restoring a Bridges drill.
Sizes include 0.152" = 3.85mm major diameter, 36tpi, and 0.136" = 3.45mm, ~38tpi
__________________
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10th Mar 2024, 5:45 pm
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#2 |
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Dekatron
Join Date: Jun 2013
Location: East Sussex, UK.
Posts: 3,327
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Re: Screw threads in Bridges drill?
I suspect they are a coarse thread especially made for use into the diecast alloy of the housing. A sort of self tapping screw.
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10th Mar 2024, 10:57 pm
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#3 |
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Dekatron
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
Posts: 5,354
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Re: Screw threads in Bridges drill?
No experience with Bridges, but the tapped holes for the screws for the flex grip in dad's 1950's Black and Decker are UNC. From my screw thread book, the 36tpi screw dimensions correspond with 8-36 UNF. Don't know about the 38tpi one. 4BA pitch is about 38.5 tpi, but the major diameter is somewhat larger at 3.6mm.
Unified screw threads seem to have been used for some UK-manufactured products in the 1950's. Dad's Selecta Home Workshop uses unified fasteners. Perhaps export markets were envisaged? Last edited by emeritus; 10th Mar 2024 at 11:15 pm. Reason: typos |
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