I bought a new brass number for my house - made by Prima Lite (Brass) Ltd. It has a hidden fixing of two pins that screw into the back of the number. I would prefer to use a long bolt through the wood on which I intend to mount it. The diameter of the screw is bout 4.5mm but the thread is coarser (but well-made) than M4.5.
Any ideas what such a thread might be?
Geoff
Give them a ring??
01296 611800Primalite Brass Ltd Unit, 5-6 Triangle Business Park Aylesbury, Buckinghamshire HP22 5BL
Baz
Thanks, I have sent them an email but I was not banking on a reply - they make a lot of trade only.
3/16" BSW is 4.76mm Dia with a 24 TPI.
2 BA is 4.70mm Dia with a TPI of 31.6 TPI
Baz
2BA and 5mm are very close - 2BA will go easily through several mm of 5mm, but not so easy the other way round. When I was refurbishing an old bike frame it was v. little effort to run a 5mm tap through the 2BA eyes so that I could use st. st. cap-head screws.
The pins seem to have 7 turns of thread measuring 0.28" = 25 turns per inch. The thread diameter = 4.58- 4.61 mm - there is a slight taper. The pin points are exactly 3.5" apart which makes me think this is an imperial job, probably made in India (non the worse for that, the product is excellent and I am looking forward to making the board to mount it on my cast iron railings. It is because it will be on the railings, rather than a front door, that I am trying to avoid a nedlet pulling it off.
Geoff
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