Small Hex Fastenings

[Ron LadenParticipant @ronladen17547]

Thanks Neil, thats promising.

Ron

[TrickyParticipant @tricky]

The pre-war Whitworth bolt sizes were bigger, 1 " bolt was 1.67" so 5BA nut on 5BA bolt seems about right!

Richard

[Howard LewisParticipant @howardlewis46836]

If all else fails, and you can source "correct" size A/F bar, how about making the Nuts and Bolts that you need?

PITA if you have hundreds to do, but not so bad if you only need half a dozen of a size.

During WW2, to save material, Whitworth and BSF hexagons were changed to the next size down, so a 5/16 BSF spanner then operated on a 3/8 BSW fixing, and so on.

Howard

[Ron LadenParticipant @ronladen17547]

Thanks Howard, as you say no fun if high numbers are needed but it has crossed my mind about making some if I only need a small batch of a particular size.

Ron

[JonParticipant @jon]

M2 here Ron, can have to 10 £2.60 to 100 off less than £11 delivered, downside theyre stainless.
https://www.ebay.co.uk/itm/M2-M2-5-M3-M4-Metric-Standard-Pitch-A2-Stainless-Steel-Hex-Head-Bolts-Screws/291244203870?hash=item43cf81df5e:m:mmZI1-ZU5aTmnrvk5Ol0UIw:rk:14f:0

Going back 8 years the only European manufacturer of production screws was Holokrome in NL. From a good source who imports and sells to the shops in UK most screws were back then made in china. Long gone are the days of Unbrako and Holokrome up Scotland till the early 90's.
There are specialist screw manufacturing but costly.

[duncan webster 1Participant @duncanwebster1]

Posted by JasonB on 06/11/2018 13:20:48:

Posted by duncan webster on 06/11/2018 12:39:32:

4mm A/F on M3 looks silly, I bought some and never used them. It it were a 5 BA bolt with a 6 BA head it would be 0.193 AF which is near enough 5mm. 5BA nut is 0.221" near enough the same as M3 which is 5.5mm

Suppose it depends on what you are modeling.

2" whit nut is 1.38D

Standard M3 nut is 1.83D

6BA hex on 126" 5 BA thread is 1.54D

5BA hex on 5BA thread is 1.75D

4mm hex on M3 is 1.33D

I know which one is closer

Edited By JasonB on 06/11/2018 13:22:33

If prototype is pre WW2 the nuts will be to BS190, and 2" bsw would be 3.15" AF, which is 1.585D, 1.5" BSW is 2.4" A/F, 1.6D. Post war were to BS 1082, one size down. Even then 1.5" BSW would be 2.22" A/F, 1.48D

[egaParticipant @ega]

Posted by Howard Lewis on 06/11/2018 16:55:23

…

During WW2, to save material, Whitworth and BSF hexagons were changed to the next size down, so a 5/16 BSF spanner then operated on a 3/8 BSW fixing, and so on.

Can anyone confirm my faint impression that this development had started pre-WW2?

I seem to remember that my 1931 Austin Seven had fastenings with the reduced size hexagons and that this caused me some confusion when buying my first spanners.

[orvilleParticipant @orville]

Just a quick reminder that BA threads ARE metric.

[Neil WyattModerator @neilwyatt]

Posted by orville on 25/11/2018 16:00:34:

Just a quick reminder that BA threads ARE metric.

But originally defined as the Imperial equivalents, just to add further confusion

"5. The question of the introduction of the metrical system occupied the serious consideration of the committee, but, considering the fact that it is not generally adopted in engineering or manufacture in England, and that it is as yet little understood by our workmen, it was thought better to suggest no change in this direction. The committee is not insensible to the simplicity of the metrical system and to its possible universality, nor to the fact of its gradual introduction in scientific circles, but while the manufacturing interests are still wedded to the British inch, and its multiples and sub-multiples, and while the British legal standard of length is still the yard, the Committee has felt it impossible to suggest a change which has little chance of adoption, and which might jeopardise the introduction of that with which they are more concerned—viz., a uniform screw-thread.

"Hence it was determined that the unit of length taken should be the ‘mil,’ and that the decimal system should be adopted for expressing dimensions."

(First Report of the BA Committee – 1mil = 0.001" )

They did, in their second report, agree to using millimetres to set the sizes, but defined imperial equivalents at the same time, the argument being that each size shoudl be known by its number not its size.

They also pointed out how useful 13BA at 2.5mm pitch might be for various purposes.

Neil

Edited By Neil Wyatt on 25/11/2018 16:41:51

[JasonBModerator @jasonb]

Posted by Neil Wyatt on 25/11/2018 16:33:21:

They also pointed out how useful 13BA at 2.5mm pitch might be for various purposes.

Neil

Edited By Neil Wyatt on 25/11/2018 16:41:51

I hope they did not

[Rod AshtonParticipant @rodashton53132]

If I could post a mild aside. Does anyone supply the unthreaded rod for 10BA, 8BA, etc.

[Neil WyattModerator @neilwyatt]

Posted by JasonB on 25/11/2018 17:07:35:

Posted by Neil Wyatt on 25/11/2018 16:33:21:

They also pointed out how useful 13BA at 2.5mm pitch might be for various purposes.

Neil

Edited By Neil Wyatt on 25/11/2018 16:41:51

I hope they did not

[Neil WyattModerator @neilwyatt]

Going back to the original point of this thread, I tried out some 6BA nuts this evening.

My 3/4" screws have heads that fit my 6BA nut spinner. I have 6BA nuts that fit my 5BA and 7BA spinners…

Neil

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