UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Other Vintage Household Electrical or Electromechanical Items

Notices

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.

Reply
 
Thread Tools
Old 5th Jul 2022, 1:20 pm   #1
Christophe9
Diode
 
Join Date: Aug 2020
Location: Rugby, Warwickshire, UK.
Posts: 5
Default Anglepoise 1227 and 75 screw threads

This refers to older Herbert Terry lamps, c.1948-1973. A thread on this forum a couple of years ago concluded that the smaller hinge nuts and bolts are threaded 6BA and the larger tensioning bolt and it's (frequently missing) knurled thumb-wheel are 5BA. I recently had to find a replacement nut for the bolt which connects the fork with the base and found by experience that I had been mistaken in saying it was 1/4" Whitworth. The nut fits a 1/4" Whitworth spanner alright but the thread is 5/16" 26tpi which is not Whitworth or BSF but BSC (cycle thread). M8 Fine thread is so close to 5/16" BSC as to be interchangeable with it. The base nut will rarely be missing but as a Google search for "Anglepoise threads" points to this site I thought it was worth putting the record straight.
Christophe9 is offline   Reply With Quote
Old 5th Jul 2022, 2:21 pm   #2
Trifocaltrev
Hexode
 
Trifocaltrev's Avatar
 
Join Date: Nov 2013
Location: Lancing, West Sussex, UK.
Posts: 253
Default Re: Anglepoise 1227 and 75 screw threads

Hi, I think you will find the thread is 5/16th BSB (British Standard Brass) and not BSCy. The BSB thread is 55 degrees as is the BSW angle and the BSCy is 60 degrees so therefore they are not interchanable. BSB nuts sizes are the same as whitworth ones.

All BSB threads are 26tpi regardless of their diameter.

Regards
Trevor.

https://en.wikipedia.org/wiki/British_Standard_Brass
Trifocaltrev is offline   Reply With Quote
Old 5th Jul 2022, 3:13 pm   #3
Christophe9
Diode
 
Join Date: Aug 2020
Location: Rugby, Warwickshire, UK.
Posts: 5
Default Re: Anglepoise 1227 and 75 screw threads

The thread appears to me to be 60 degrees (from measuring of an enlarged photograph of the shank). M8 fine (1mm pitch, 25.4 tpi 60 degrees) fits very well indeed. In practice, for this particulÓr purpose, 5/16 BSB, 5/16 BSCy, or M8 fine would all work.
Christophe9 is offline   Reply With Quote
Old 5th Jul 2022, 3:29 pm   #4
Nickthedentist
Dekatron
 
Nickthedentist's Avatar
 
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 16,488
Default Re: Anglepoise 1227 and 75 screw threads

And I can indeed confirm that 5BA works for the knurled nut, as you've said.
Nickthedentist is offline   Reply With Quote
Reply

Thread Tools



All times are GMT. The time now is 11:53 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2022, vBulletin Solutions, Inc.
Copyright ©2002 - 2021, Paul Stenning.