Yorkie Posted March 3, 2017 Share Posted March 3, 2017 I've taken apart a couple of old green Patt 223's to rewire them but have stripped the heads on some of the assembly screws in the process. They seem to be slightly bigger than a M3.5 and smaller than an M4. I guess they are sort of imperial machine screw but I have no idea. Does anyone here know what size they are so I can find replacements? Link to comment Share on other sites More sharing options...
timsabre Posted March 3, 2017 Share Posted March 3, 2017 Well you have the choice of whitworth, BA or BSF threads for that era of UK built device. 4BA is 3.6mm across the outside of the threads so that sounds likely if it is just a little bit bigger than M3.5 see https://en.wikipedia...n_screw_threadsand https://en.wikipedia...ndard_Whitworth Link to comment Share on other sites More sharing options...
Whiskers Posted March 3, 2017 Share Posted March 3, 2017 + 1 for BA Link to comment Share on other sites More sharing options...
Don Allen Posted March 4, 2017 Share Posted March 4, 2017 I have an exploded diagram for the Pattern 123 Fresnel Spotlight and Accessories - screws used areIndex 22 Screw 2BA x 7/8" Csk. (with circlip groove) qty 1 for lamp focus knobIndex 30 Hex Bolt 3/8" Whit. x 1 1/2" qty 1 - for hook clamp Index 31 Screw 2BA x 3/8" Ch. Hd. qty 1 - holds reflector onto slideIndex 32 Screw 4BA x 9/16" Ch. Hd. qty 2 - cable clampIndex 33 Screw 4BA x 7/16" Ch. Hd. qty 2 - lampholder slideIndex 34 Screw 4BA x 7/16" Csk. qty 2 - part of lamp catchIndex 35 Screw 4BA x 5/16" Csk. qty 4 - part of lamp slideIndex 36 Screw 4BA x 1/4" Ch. Hd. qty 1 - earth clamp In summary, the early Pattern series of lanterns used BA screws. You should be able to find locally, or tap out to a metric thread, or ask someone on the forum if they have spare screws. Link to comment Share on other sites More sharing options...
timsabre Posted March 4, 2017 Share Posted March 4, 2017 Lots of people on ebay will sell you BA screws or try RS. Link to comment Share on other sites More sharing options...
xllx Posted March 4, 2017 Share Posted March 4, 2017 I've taken apart a couple of old green Patt 223's to rewire them but have stripped the heads on some of the assembly screws in the process. They seem to be slightly bigger than a M3.5 and smaller than an M4. I guess they are sort of imperial machine screw but I have no idea. Does anyone here know what size they are so I can find replacements? Strand stuff from that era is pretty much all BA screws. They are readily available, have a look on ebay, Amazon and model engineering and car restoration companies. I think I bought my last batch and some BA taps from http://www.ba-bolts.co.uk/ Link to comment Share on other sites More sharing options...
Yorkie Posted March 4, 2017 Author Share Posted March 4, 2017 Super info, thanks gents. Will now be looking for some 4BA 1/2" pan pozi Link to comment Share on other sites More sharing options...
Barreller Posted March 4, 2017 Share Posted March 4, 2017 Super info, thanks gents. Will now be looking for some 4BA 1/2" pan poziFor authenticity they're probably Phillips, not Pozi!! Link to comment Share on other sites More sharing options...
Yorkie Posted March 4, 2017 Author Share Posted March 4, 2017 Super info, thanks gents. Will now be looking for some 4BA 1/2" pan poziFor authenticity they're probably Phillips, not Pozi!! Good point, I think that's how I messed 'em up in the first place Link to comment Share on other sites More sharing options...
CPlater1 Posted March 4, 2017 Share Posted March 4, 2017 If you were in Bristol, there is a shop called Stones that stock BA and can get Whitworth. Just putting it here to help future people! Link to comment Share on other sites More sharing options...
Kazeja Posted March 6, 2017 Share Posted March 6, 2017 According to my drawings of the 223, the screws used are 2, 4 and 6 BA various lengths. If you want, then next time I'm standing near an A3 scanner I'll email you a copy of the exploded diagram.K Link to comment Share on other sites More sharing options...
trussmonkee Posted March 11, 2017 Share Posted March 11, 2017 Just putting this out there, how about tapping it out and using metric? Link to comment Share on other sites More sharing options...
Barreller Posted March 11, 2017 Share Posted March 11, 2017 Just putting this out there, how about tapping it out and using metric?Why? Link to comment Share on other sites More sharing options...
Whiskers Posted March 11, 2017 Share Posted March 11, 2017 Just putting this out there, how about tapping it out and using metric? BREXIT? Link to comment Share on other sites More sharing options...
Jivemaster Posted March 12, 2017 Share Posted March 12, 2017 www.clerkenwellscrews.com/ is my go to place for odd screw threads. They do have a minimum charge though. Link to comment Share on other sites More sharing options...
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