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Using Whitworth nuts and bolts
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Albioninoz



Joined: 23 Mar 2015
Posts: 8
Location: Melbourne, Australia

PostPosted: Wed Jun 17, 2015 12:17 pm    Post subject: Using Whitworth nuts and bolts Reply with quote

Hi, I'm new to this forum and relatively new to car restoration. I had a Rover P6B for 12 years but only every did light restoration on it as it was in very good condition when I bought it. However, I did pull the front brake calipers off and totally restore them with new pistons, seals etc.
Now I have a 1957 Rover P4 which is in need of much deeper restoration but nothing I can't handle (I think so anyway!). My question revolves around the fact that the majority (or it could be all) of the nuts & bolts are Whitworth (BSW) thread. If they were AF or metric, finding a spanner and socket to fit would be no problem. I have bought myself a set of BSW sockets and spanners but I will need to replace some nut and bolts where others have been damaged. In the cause of originality I would replace all with BSW but I fear this would be impractical. Therefore I will replace some with AF but others will need to be BSW. For example where there is a fixed bolt or stud and the nut was damaged. After all that preamble, my question is if a nut is advertised as 3/16th BSW, would a 3/16th spanner (or socket) fit that nut? Is there a correlation between the inside thread (of a nut) to the outside dimensions. Sorry if this seems a dumb question to ask but it is my first experience with BSW threads. Also, I am in Australia so BSW is even rarer here. Thanks Confused
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Penguin45



Joined: 28 Jul 2014
Posts: 381
Location: Padiham

PostPosted: Wed Jun 17, 2015 12:26 pm    Post subject: Reply with quote

You need to have a read on BACONSDOZEN. Very informative. He's a regular on here as well, so will no doubt help.

P45.
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PAUL BEAUMONT



Joined: 27 Nov 2007
Posts: 1281
Location: Barnsley S. Yorks

PostPosted: Wed Jun 17, 2015 12:47 pm    Post subject: Reply with quote

Hi, Whitworth and BSF spanner jaw sises relate to the diameter of the fastener, not to the head of the fastener as is the case with A/F and Metric.
Most BSF and Whitworth fastener sizes are still fairly available in the UK - in particular Spalding Fasteners comes to mind. They have an eBay shop so should be able to help, but before you ship nuts half way round the world it is certainly worth dropping on on the oldest fastener stockist that you can find locally. Many stock a good selection of such products in the UK as much industrial plant and railway equipment was equipped with such fasteners originally and is still being maintained.
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peter scott



Joined: 18 Dec 2007
Posts: 7113
Location: Edinburgh

PostPosted: Wed Jun 17, 2015 3:53 pm    Post subject: Reply with quote

See also: http://www.namrick.co.uk/
http://www.thomassmithfasteners.com/
http://www.stainlessautomotivefastenings.co.uk/index.php?main_page=index&cPath=79&sort=20a&page=1

Using wrong nut and bolt types will not improve the value of your car but I guess it might not be spotted by a future buyer.

Peter
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ukdave2002



Joined: 23 Nov 2007
Posts: 4100
Location: South Cheshire

PostPosted: Wed Jun 17, 2015 5:26 pm    Post subject: Reply with quote

We are mixing up threads and spanner sizes, but we know what you mean Smile

I'd imagine the threads will be mainly BSF, the "Whitworth" spanners or sockets you have bought will fit both Whitworth bolts or BSF, hence each socket size has 2 different markings.

Cheers

Dave
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goneps



Joined: 18 Jun 2013
Posts: 601
Location: Auckland, New Zealand

PostPosted: Thu Jun 18, 2015 1:31 am    Post subject: Reply with quote

Some time ago I wrote the article below in an attempt to clear some of the confusion on this subject. It's aimed principally at owners of pre-war Morris cars, but is equally applicable to other British marques. Without any specific knowledge of Rovers I'd agree with Dave that most of the fasteners are likely to be BSF, not BSW, although it was around the late 'fifties that British manufacturers were starting to switch to UNF threads.

Prior to this article I'd written a similar dissertation on the subject of engineering fasteners and thread types, and can post this if it might be of interest.

Richard

A Note About Spanner Sizes

Tools designed for Metric and SAE (UNC/UNF) fasteners are marked according to the size of the fastener hexagon (nut or head of bolt) they're designed to fit, so for instance an 8mm bolt has a 13mm head and therefore requires a 13mm spanner. On the other hand, spanners designed for British fasteners (BSF/BSW) are marked according to the thread diameter of the fastener, so the jaws of a 3/16"W spanner are a lot wider than those of a 1/4"A/F.

Spanners intended for use on SAE fasteners are marked A/F, which stands for the Across the Flats size (not the common misperception of “American Fine”—there is no such thing). The only Unified (SAE) thread on the Morris Eight that comes to mind is that of the four slave cylinder bleed nipples (Lockheed being of American origin), but even then the hexagon is a British size, accepting a 1/8”W spanner. Tools marked A/F are of no use for the vintage Morris.

Confusingly, spanners marked W, BS, or BSF are all suitable for BSF and BSW bolts. Originally the hexagons of BSF fasteners were one size smaller than those of the same size Whitworth fasteners. For instance, a 5/16"BSF bolt would have the same size head as a 1/4"BSW—or, to put it the other way, a 5/16"BSF bolt would have a one-size-smaller head than a 5/16"BSW bolt. This is not as daft as it might seem at first glance, because the finer BSF thread gives more mechanical advantage than the coarser BSW thread and is thus prone to over-tightening. With the smaller head this is compensated for by the spanner being slightly shorter.

However, at some stage—post-war, I believe—it was decided to standardise the hexagon sizes for the two threads, so from that point on BSW fasteners were manufactured with the smaller head size. Simultaneously the terminology used on tool markings was changed to simple BS, implying that the spanner would be correct for British Standard nuts and bolts of that shank size, regardless of thread type.

In my experience not all spanners are correctly marked according to these criteria, and some tools are marked with both the W and BSF size. Since not many mechanics will whip out a vernier and measure the bolt size before selecting the appropriate tool it's largely academic. As long as the tool is marked BSF, W, BSW, or BS, and is a snug fit on the hexagon of a BSF or W fastener, it's the right one for the job.

BA (British Association) is a standard for small threads and used extensively on Lucas electrical equipment. BA is a bit of a mongrel, with thread diameter and pitch quoted in mm., but conforms to the same principle of spanner sizes as the larger British threads. In other words, you should use BA spanners for BA fasteners, although they’re expensive. The common sizes on the Morris Eight are 2BA and 4BA. Most of the brass terminal nuts on coil, dynamo, instruments, etc. are 2BA. The smaller the BA number, the larger the fastener, so 0BA is the largest.
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Albioninoz



Joined: 23 Mar 2015
Posts: 8
Location: Melbourne, Australia

PostPosted: Thu Jun 18, 2015 3:29 am    Post subject: Using Whitworth nuts and bolts Reply with quote

Thanks to all the replies. It has made me realise that my question was maybe not so stupid after all!

Cheers,

Ray
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MikeEdwards



Joined: 25 May 2011
Posts: 2466
Location: South Cheshire

PostPosted: Thu Jun 18, 2015 10:22 am    Post subject: Reply with quote

goneps wrote:
On the other hand, spanners designed for British fasteners (BSF/BSW) are marked according to the thread diameter of the fastener, so the jaws of a 3/16"W spanner are a lot wider than those of a 1/4"A/F.


Thanks for that. I have quite a few Whitworth spanners and it's always intrigued me as to why the spanner head was marked in the way it was. Not enough to actually search it, which would have provided an answer pretty quickly, but interesting nonetheless.
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goneps



Joined: 18 Jun 2013
Posts: 601
Location: Auckland, New Zealand

PostPosted: Fri Jun 19, 2015 12:38 am    Post subject: Reply with quote

When you think about it, the Imperial (by which I mean British) system is the more sensible. Instead of having different nominal sizes for the fastener and spanner, a 3/8" spanner fits a 3/8" bolt or nut. I spent some years in the fastener business, and wouldn't mind a quid for every time someone came in and asked for a 13mm bolt (there's no such thing, of course), because that was the size of spanner he'd used on it.

Similarly, BSF is the ideal thread for engineering fasteners. Standard Metric and UNC are too coarse, Metric fine and UNF are too fine, but BSF is the ideal balance between the two, being more resistant to loosening than the former and more resistant to stripping than the latter. Whitworth is really redundant, since it was designed in the mid-19th century when the quality and strength of steels were too poor for anything but a coarse thread.

Richard
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Peter_L



Joined: 10 Apr 2008
Posts: 2680
Location: New Brunswick. Canada.

PostPosted: Fri Jun 19, 2015 1:57 am    Post subject: Reply with quote

A little more information here

http://www.team.net/sol/tech/whitworth-hist.html

I started work with the Coal Board in 1962. We often came up against older equipment with the larger (across flats) bolts and nuts.

A lot of flameproof equipment (FLP) continued using the large headed bolts. The larger bolt/nut head area was said to provide better FLP protection by covering more area.

Also here, more info on bolts and spanners and threads

http://www.sat.dundee.ac.uk/psc/spanner_jaw.html
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greenbeam



Joined: 10 Jun 2015
Posts: 85
Location: Adelaide, Australia

PostPosted: Wed Aug 19, 2015 1:27 pm    Post subject: Reply with quote

Albioninoz,
Not sure about who to talk to in Melbourne, but in Adelaide we have: http://www.classicfasteners.com.au/

Their website has s section on British Threads.

Regards,
Paul.
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Da Tow'd



Joined: 16 Jun 2010
Posts: 349
Location: Bella Coma British Columbia Canada

PostPosted: Tue Nov 17, 2015 11:35 pm    Post subject: Reply with quote

I have the pleasure of working on a 34Ft. Pleasure boat with twin Perkins turbo diesels, replacing one of the Borg Warner Velvet Drive marine transmissions.
The transmission has mounts on both sides to the engine bed timbers.
The nuts on the adjustable transmission mounts were on pretty tight, my sae 1 1/8" tools and metric sockets felt real sloppy both 6 point and 12.
I found a odd ball socket in my miscellaneous tool box that fit
the socket that had this stamped with on it's side
SW71-D- 1 - 5/8(made in USA)
the fit was perfect and with a 3/4" ratchet and lots of heat and wax on the rusty nut it came off.
I know Perkins engines are made in the UK
I'm wondering if those nuts on those mounts are whitworth?
no blood lost on working on it
cheers
Hank
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goneps



Joined: 18 Jun 2013
Posts: 601
Location: Auckland, New Zealand

PostPosted: Wed Nov 18, 2015 12:03 am    Post subject: Reply with quote

I should have thought it more likely to be BSF, Hank, but it might be either 11/16"BSF (14tpi) or 5/8"W (11tpi).

The nominal A/F size of a 5/8"W spanner is 27.94mm, whereas your 1 1/8"A/F would of course be 28.575mm.

Richard
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Da Tow'd



Joined: 16 Jun 2010
Posts: 349
Location: Bella Coma British Columbia Canada

PostPosted: Wed Nov 18, 2015 1:33 am    Post subject: Reply with quote

thanks Richard
very interesting
Hank
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