Chart for distance flat to flat small imperial bolts wanted

Rhino Rhino for Windows
1

Hi,
Absolute useless internet
i need a chart of small bolt sizes, not 1/4inch but smaller.
they all start at 1/4 inch, but I am reverse engineering things with smaller than that., so I know such exist !

Has anyone such a chart showing what imperial bolt head sizes exist as IMPERIAL ?

and nuts to go with them, clearance holes and thread data also welcome.

featuring a drawing of what dim A is and B is etc,

normally A is flat to flat, but sometimes S is that, there is no standardisation on this !

This when I get it is going in my useful references folder !

Cheers

Steve

2

Do you mean SAE course and fine, or some British standard?

3

@Steve1 Several different imperial bolt sizing systems were used in Britain for bolts smaller than 1/4 diameter including BA, BSW, BSF and Unified.

Website with charts of bolt, nut and washer dimensions with pages
“BA”
“Imperial” which includes BSW and BSF - difference is thread pitch
"Unified

4

Try here: https://www.mcmaster.com/

5

Hi,
Rhanks for the links.
I am dealing with World War Two and just prior, nuts and Bolts.
so the BA chart had a 0.282 and my section through photogrammetry had 0.2804 so thats probably it.

Was BA in use in WW2 ?

I see in Wikipedia
BS 57:1951 — B.A. screws, bolts and nuts
BS 93:1951
which is after WW2

McMaster is a bewildering set of items, just wish to see a WW2 imperial chart of bolts.

Cheers

Steve

6

Yes.

BA (British Association) screw threads are named after the British Association for Advancement of Science and were put together in 1884 and standardised and published in 1903. https://www.fastenerdata.co.uk/ba-threads#:~:text=BA%20(British%20Association)%20screw%20threads,bigger%20numbers%20denote%20smaller%20screws.