BSF and Whitworth “Across the flats ” sizes.

[Adrian GilesParticipant @adriangiles39248]

A well known German company started supplying their garden shredders with a 5 point centre pin security screw to hold the two main parts together, where previously one way slip screws had been supplied. Guess where the only place you could obtain the required tool to do them up with came from? They charged us nearly ten quid for the bit to fit your normal hex driver! And these machines were supposed to be assembled by Joe Public!

[Brian GParticipant @briang]

Just found this – not much (or indeed any) use for BS/BSF/BSW, but perhaps explains why there are so many spanners in a metric set. Evidently metrication != standardisation. **LINK**

Brian

[egaParticipant @ega]

Brian G:

That useful table seems to confirm that 15mm AF is not standard.

[David Standing 1Participant @davidstanding1]

Posted by Brian G on 09/10/2017 10:52:57:

Posted by Chris Evans 6 on 09/10/2017 09:46:11:

…Nearly all brakes I have worked on over the last few years use a 7mm allen key on the slider pins, another size not seen in general engineering use..

And you couldn't just buy a standard key in that size, it has to be the special automotive one with a sleeve handle

Brian

I still have that special automotive Allen key with the sleeve handle I bought in about the mid eighties, and I don't think I have used it since!!

[VicParticipant @vic]

I still have a plain Snap-On 7mm hex (Allen key) socket from when I used to be a Ford mechanic. We also used 15mm spanners on fords in the 80's.

[Carl Wilson 4Participant @carlwilson4]

A friend of mine always uses an 18mm spanner to unscrew the cap on 45 gallon oil drums. When asked why he said it’s so that it has a job to do, and doesn’t feel left out.

Similarly, I occasionally use the 14mm instead of a 9/16ths just to keep its hand in.

[Andy PughParticipant @andypugh44463]

To resurrect a zombie thread..

There is one exception. One of the big-head Whitworth heads did not have a BSF equivalent.

http://www.oldengine.org/members/diesel/Tables/WhitAF.htm

The old 5/8 Whit at 1.10 AF had no BSF equivalent.

I have found it _very_ hard to find a 1.10" spanner for our old fire engine. (1916)

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Andy Pugh on 12/09/2020 02:48:19:

[…]

I have found it _very_ hard to find a 1.10" spanner for our old fire engine. (1916)

.

That’s strange

Simple logic suggests that a spanner for 11/16” BSF should fit.

MichaelG.

 

Edited By Michael Gilligan on 12/09/2020 07:42:45

[Michael GilliganParticipant @michaelgilligan61133]

Too late to edit my previous post

This seems a handy reference chart: **LINK**

http://classicmechanic.blogspot.com/2011/06/mm-af-bsw-bsf-spanner-conversion-chart.html

MichaelG.

[Nick Clarke 3Participant @nickclarke3]

Posted by Mike Poole on 08/10/2017 22:56:48:

Volkswagen also use odd sizes,

When I used to have an elderly VW Beetle as a daily driver I noticed that any through bolt, not that there were many on a car of course, had a different sized head to the securing nut.

Asking the Beetle expert who did the major works on my car, apparently it was because the early cars came with a full tool kit and of course you don't get two spanners the same size.

Mine, though old, was long past those days, but the practice still prevailed.

[Howard LewisParticipant @howardlewis46836]

If not already said, BSF size is one up from BSW, i.e Spanners are often identified as "5/16 BSW / 3/8 BSF"

During WW2, to save material the hexagons sizes were decreased, so that a pre war 1/4 BSW / 5/16 BSF spanner would now fit 5/16 BSW / 3/8 BSF.

The size across flats was decided by a formula related to the nominal thread size.

Unified (And the preceding ANC and ANF, sometimes referred to as Sellars) use an Across flats size which is not related to thread size in this way. In some instances, for convenience,the A/F size will differ from the "norm", posibly one size smaller

Metric fasteners also have A/F sizes supposedly fixed in the same way, so that 13mm spanner usually fits a M8 fixing. But, again variations do occur. Renault used 12mm A/F nuts on 8mm studs to secure the carburretor on the Renault 5, instead of the expected 13mm. I have seen many M6 bolts or setscrews with 8mm heads rather than the ususal 10mm A/F., whilst the associated nuts are 10mm A/F..

A real hybrid combination were the bolts used to secure the Borg and Beck 14AS clutch to the Flywheel of the Gardner 6LW engine in manual transmission Bristol RE buses. These were 5/8 A/F, but with 5/16 BSF threads to suit the still Whit standard Gardner engine! Even worse, the Bell Housing was retained by nine 3/8 BSF bolts, and three studs with 3/8UNF threads!l A fitter's nightmare.

I have to confess that my workshop contains some 17mm A/F nuts with non metric threads, on items that are not intended to be slackened again.

Howard

[john halfpennyParticipant @johnhalfpenny52803]

Morris were notorious pre- and just post-war for using metric threads with imperial heads, owing to the parsimonious Bill Morris acquiring some metric threading tools with the Hotchkiss engine plant in Coventry.

[Andy PughParticipant @andypugh44463]

Posted by Michael Gilligan on 12/09/2020 07:42:14:

Simple logic suggests that a spanner for 11/16” BSF should fit.

I don't think that 11/16BSF appears in BS1083 or BS190. None of our sets (King Dick and Britool) seemed to include it. And if you go to the bolt shops they don't have that size (though taps and dies are readily available)

The big-end bolts on the fire engine are actually 11/16 BSF. Amazingly it survived for years with 3/4 BSF nuts on there, the pitch difference and size difference seemed to conspire to torque up and hold OK. When we discovered the error I seem to recall we had some nuts specially made. But the nut AF size matches a spanner so probably isn't 1.10"

[Howard LewisParticipant @howardlewis46836]

When BMC was formed, the wheel bolts for the Morris Minor changed from BSF to UNF, The UNF threaded parts were identified by a "nick" on each corner of the hexagon. This was along with the side valve Morris engine and gearbox being replaced by the 803 cc A Series engine and a horrid and unreliable gearbox.

Howard.

[Bill PhinnParticipant @billphinn90025]

 

Posted by Andy Pugh on 12/09/2020 12:17:30:

Posted by Michael Gilligan on 12/09/2020 07:42:14:

Simple logic suggests that a spanner for 11/16” BSF should fit.

I don't think that 11/16BSF appears in BS1083 or BS190. None of our sets (King Dick and Britool) seemed to include it. And if you go to the bolt shops they don't have that size (though taps and dies are readily available)

 

 

Pictured is the spanner that at the moment I probably use most of all the spanners I possess [for the flats on my ER25 collet chuck]. It is a very good fit, partly because the jaws of the spanner are exactly the same thickness as the width of the chuck's flats.

ETA: It is the 5/8-11/16 end I use.

Edited By Bill Phinn on 12/09/2020 13:29:02

[Andy PughParticipant @andypugh44463]

Posted by Bill Phinn on 12/09/2020 13:27:14:

Pictured is the spanner that at the moment I probably use most of all the spanners I possess

It looks like a BS190 spanner, so yes, it will fit an old 5/8"W bolt head. My point was that modern Whitworth spanner sets do not always include the 1.10" AF size.

I haven't yet found a BS1083 table that lists the "new" 11/16"BSF spanner size. I strongly suspect that it doesn't exist and so to deal with BS190 5/8" bolts you need to find a spanner made before 1951.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Andy Pugh on 12/09/2020 12:17:30:

Posted by Michael Gilligan on 12/09/2020 07:42:14:

Simple logic suggests that a spanner for 11/16” BSF should fit.

I don't think that 11/16BSF appears in BS1083 or BS190. None of our sets (King Dick and Britool) seemed to include it. And if you go to the bolt shops they don't have that size (though taps and dies are readily available)

[…]

.

It’s obviously frustrating if you can’t find one, Andy … but I have just confirmed that BS 192-2:1998 [which is current] lists the wrench you need, in Table 1

MichaelG.

.

P.S. ___ For clarity, and hopefully compliant with ‘fair use’ … here is a very brief quotation from the Foreword:

This British Standard supersedes the parts of BS 192:1982 that deal with Whitworth and BS wrench sizes.

… and [should you feel the need to purchase a copy] a link to the BSI Shop page: **LINK**

https://shop.bsigroup.com/ProductDetail?pid=000000000001402890

[Bill PhinnParticipant @billphinn90025]

Posted by Andy Pugh on 12/09/2020 14:52:22:

Posted by Bill Phinn on 12/09/2020 13:27:14:

Pictured is the spanner that at the moment I probably use most of all the spanners I possess

It looks like a BS190 spanner, so yes, it will fit an old 5/8"W bolt head. My point was that modern Whitworth spanner sets do not always include the 1.10" AF size.

Right.

What might we expect it to say on it? 1 3/32"?

[Rod RenshawParticipant @rodrenshaw28584]

Interesting thread, I have often wondered about this and often used "the nearest I had handy" when in a rush. I have tried to use the link to the Handy Table posted by Brian G on 9.10.17 but it does not work for me (it is 3 years old ). Will someone post a more up to date link.

Thanks

Rod

[Michael GilliganParticipant @michaelgilligan61133]

Was the one I linked this morning [08:47:41] not good enough for you, Rod ?

MichaelG.

[Howard LewisParticipant @howardlewis46836]

My mold Britool Catalogue No 106 on page 128 quotes nominal bolt diameters as being 11/16" to the original BS 28 and BS 190, and 3/4 tot he later BS 1083 and BS 916 for black nuts and bolts.

This is for a wrench with a nominal jaw opening of 2.00

A wrench with a jaw opening of 1.1" is quoted as being for nominal diameters of 11/16" to BS 28 and BS 190 or 3/4" to BS1083, without any reference to black nuts or bolts.

If the fire engine is 1916, I would be inclined to think in terms think in terms of BS 28

It quotes the 5/8 BSW and 11/16 BSF as being wheel nut sizes used on most A E C, and Albion, some Morris Commercial and Dodge 264/P4, commercial vehicles, and the rear wheels of David Brown and international tractors. Whjich may be a source of mspanner, although being wheel nuts, I would expect them to be socket types, which may be more secure, if there is room for the socket…

Howard

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Howard Lewis on 12/09/2020 17:28:36:

If the fire engine is 1916, I would be inclined to think in terms think in terms of BS 28

.

**LINK**

https://shop.bsigroup.com/SearchResults?q=bs+28&id=161026&epslanguage=en&filter=spanners~

MichaelG.

[Howard LewisParticipant @howardlewis46836]

So BS 1912 looks to be the one to read, if you feel like joining BSI, or paying twice as much (£182 ) if you don't.

At those prices I'll believe what Britool and others tell me!

Howard

[Rod RenshawParticipant @rodrenshaw28584]

Sorry Michael, missed that one, lots of posts on this thread, but not really a good excuse.

Thanks for posting the chart.

Regards

Rod

[Michael GilliganParticipant @michaelgilligan61133]

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