[Healeys] bolt identification - another article

Mirek Sharp m.g.sharp at sympatico.ca
Sat Nov 24 15:59:12 MST 2018

Thanks Curt, we can never know too much about our bolts, or our nuts.  I use CEI a lot, as I have a couple of older BSAs and they used CEI in 95% of the applications, most, but not all of them from Rubery Owen.  One of the gurus from the Velocette club once did in fact do a quiz on fasteners at one of our AGMs.  The question was, “How many threading systems did Velocette use on their bikes?”  I cannot recall the answer, but it was surprisingly high – if I can find the answer, I will post it..  My personal favourite was “Admiralty thread”, which I seem to recall was for the top fork nuts on a Velo, and also has a Whitworth form:

British Admiralty Fine Threads
(Whitworth Form)


Under 1/2"............24
1/2" & under 3/4".....20
3/4" & under 1".......14
1" & under 2".........12
2" & under 4"..........8
4" & over..............6


Fastenerating, isn’t it?




From: Curtis Arndt [mailto:cnaarndt at gmail.com] 
Sent: November-23-18 7:39 PM
To: Mirek Sharp
Cc: Michael Oritt; John Vrugtman; Healey List; Oudesluys
Subject: Re: [Healeys] bolt identification - another article




The Charles Falco article is somewhat dated, but overall is factually correct if not complete.  I've personally spoken with Charles regarding this article.  He is correct, it is common to find UNC bolts and studs used where BSW threads were originally tapped.  I discuss this in my article with regard to the generator link adjusting bolt on BN1/2 (possibly 100-6's) and Bugeye Sprites.


One of the biggest misconceptions that I've come across (even from Brits that I know) is that the only Whitworth fasteners are BSW, and BSF, BSP, BSPT, BSB, etc... and others are somehow NOT Whitworth.  Totally untrue!  Whitworth is BY DEFINITION is...


Whitworth Screw Thread Form: A thread form and system of standard sizes, proposed by Joseph Whitworth in 1841 and adopted as standard in the U.K., having a flank angle of 55° and a rounded top (crest) and foot (root). (Named after Sir Joseph Whitworth (1803--87), English engineer). 


As you can read, Whitworth is a thread form, and NOT a hex bolt/nut size.  Note that this says NOTHING about hex head/spanner size. 


Case in point...The confusion has to do with bolt head sizing with regard to certain other British fasteners such as BSC or BSCy - (British Standard Cycle) and the older now obsolete CEI - (Cycle Engineers Institute} bolts, that while they have Whitworth hex heads, are a thread form with a 60° thread pitch angle, ergo not Whitworth.  


Are we confused yet?  Wikipedia also does not help the debate since they incorrectly list BSC bolts as Whitworth, when technically they are not.


There will be a quiz ;-^)








On Thu, Nov 22, 2018 at 9:01 PM Mirek Sharp <m.g.sharp at sympatico.ca> wrote:

Here is another article (actually an old post from another forum) on British fasteners.  It is interesting but note that the author was not clear on the pipe threads, not distinguishing BSPP and BSPT, and provides somewhat dubious advice at the end about “making do” with UNC instead of the correct fastener.  My advice – use the correct threading system and grade of bolt.  Note, that despite my earlier tongue-in-cheek comments, the BA thread system is based on metric principles, but with the unavoidable English twist.


Cheers, Mirek


From: Healeys [mailto:healeys-bounces at autox.team.net] On Behalf Of Curtis Arndt
Sent: November-22-18 3:46 AM
To: Michael Oritt
Cc: John Vrugtman; Healey List
Subject: Re: [Healeys] bolt identification




Here is some more pertinent information that might help...


I've attached a copy of my 1957 vintage machinery Handbook which shows the various markings used to denote Whitworth from Unified fasteners.


Also an excerpt from one of my yet completed articles.





Error! Filename not specified.    


On Thu, Nov 22, 2018 at 12:32 AM Curtis Arndt <cnaarndt at gmail.com> wrote:



Like most British bolts of the earlier part of last century, the Vendor name was printed on the bolt, e.g. Rubery-Owen or RO, Bees, Wiley, Woden and about 30+ others.  So to answer your question... BEES was the vendor.  The bolt you refer to with an actual Bee on the head is a very early bolt, and is one that I have in my collection.  It most likely is a Whitworth bolt, either BSF (fine) or BSW (coarse).


The  "Rubery Owen B28-35" that you refer to is a "Mild" steel bolt, similar to an SAE Grade "2" US bolt.  The strength rating is "B" and the measurement is 28 to 35 tons per square inch or tons tensile.  The range refers to "yield" strength and "ultimate tensile" strength as described in my attached article.  FYI, multiply 28 or 35 times a ton and you'll get the strength in pounds, or psi... HOWEVER  we're talking British here, so it's not 2,000 pounds as in a US ton but 2,240 pounds as in a British Long Ton!


Along with the vendor name was the strength rating expressed as a letter which for hi tensile bolts was D, E, F and G prior to 1950 and changed to R, S, T,  U,  V,  W,  and X after 1950.  I have included (attached) my draft on British Strength rating codes decoded which I hope to officially publish on my blog site once it's up and running.


Also, the bolt heads were marked to differentiate Whitworth (BSW, BSF, etc...) from UNF and UNC once this new thread form system was phased in during the early 1950s.  For bolts, that was a "circular" depression on the head of the bolt which meant the bolt was a "Unified" versus a "Whitworth" thread form bolt.


I hope this helps and email me directly if you have any further questions.








On Wed, Nov 21, 2018 at 9:01 PM Michael Oritt <michael.oritt at gmail.com> wrote:

Hi John--


Check this out:




Happy Thanksgiving to you and Cindi.


Best--Michael Oritt


On Wed, Nov 21, 2018 at 10:19 PM John Vrugtman <javrugtman at htcnet.org> wrote:


Bees bolts seem to be very obscure, saw a picture of one, but no reference to the manufacturer  

On 11/21/2018 6:58 PM, warthodson at aol.com wrote:

I was sorting thru a box of hardware & found two bolts that I cannot identify. They both are approx. 1/4" diameter. They both have the same thread per inch. According to my thread gage they are between 24 & 26 TPI. So call it 25 TPI. I do not have a metric thread gage to check them against.


One is marked "Rubery Owen B28-35" on the head & measures about 5/8" long. The other is marked "BEES" & has a embossed emblem of a bee on the head & measures about 3/4" long. The lengths do not include the head, of course. No other markings on the heads.

They will not accept a BSF nut, UNF or UNC nut or any metric nuts that I have. 


Can anyone ID these for me?



Gary Hodson   



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