162 replies to this topic

[MRA]

Excellent that means I don't have to draw anything!

No there is no description of the root of Unified threads in the stanadard, that's because they were originally flat bottomed as well as flat topped. That made them very weak. They were invented in 18 something or other though at the dawn of standardisation and industry in America and at the time people didn't know that a radius would be stronger (although Whitworth already had radii in his thread at this time). As cutting tools wore out the threads produced developed a radius and people noticed the radiused thread was stronger. For details of a standard for the root radius look up UNJF or UNJC, these are aeropsoace threads. I don't know whether people apply this specification to regular UN fittings now or not but there is at least a standard there.

As for WF, I'm never going to accept that there is a Whitworth Fine. Whitworth was the first and original standard thread, the first one ever. Before Joseph Whitworth threads were custom made for every machine or fitting and nothing was interchangeable. When the thread was adopted as BSW it should have become BSC but didn't out of respect for the man and for history. There was never a fine thread devised by Whitworth, he created one singl thread and specified it from 0.1" 48 tpi to 6" 2.5 tpi. All the derivitives of his thread were made later by others and so have BS names. There are many besides BSW and BSF including BSCy, BSB, BSP, BSPT and others but none of them has 16 tpi at 5/8". This is a custom thread, plain and simple. It may appear in other parts of various Austin engines and they may have originally designed it but it is not on any standards tables. People in other countries may refer to BSF as Whitworth but they are not right. This tap may have had WF stamped on it by a Chinese machine shop but they aren't right either. Then again, WF could be the name of whoever made it.

A "J" type UN thread form is what is known as a "controlled" root radius not specifically for Aerospace use as you will find them on your Mini, but thats another topic........ Controlled root radii are simply that the root radii has a tolerance that is controlled and therefore between certain limits.

Edited by mra-minis.co.uk, 30 March 2009 - 11:22 PM.

[Nightrain]

So now we come full circle and your adding MG's to my list, this is really sad you weren't around at the time none of us where and because it doesn't refer to a Whitworth Fine Thread on the internet it can't of existed. I can see I have put a lot of noses out of place. First off it wasn't a whitworth thread then after you've heard from a few people with more expertise than yourselves you all change your mind.
What a *melonsing* Joke.

Oh by the way I never mention BSF as I unlike all the internet wizards above know that BSF is a totally different pitch. An expert is someone who doesn't stop learning, but it appears I was wrong and there aren't any on here !

Edited by Nightrain, 30 March 2009 - 11:30 PM.

[MRA]

So now we come full circle and your adding MG's to my list, this is really sad you weren't around at the time none of us where and because it doesn't refer to a Whitworth Fine Thread on the internet it can't of existed. I can see I have put a lot of noses out of place. First off it wasn't a whitworth thread then after you've heard from a few people with more expertise than yourselves you all change your mind.
What a *melonsing* Joke.

Oh by the way I never mention BSF as I unlike all the internet wizards above know that BSF is a totally different pitch. An expert is someone who doesn't stop learning, but it appears I was wrong and there aren't any on here !

FYI this is direct from the BSI website........ Whilst I understand you may be upset, by the comment that Whit fine does NOT exist BSI is the governing body for Standards and specifications within the UK ............... here it is below

This British Standard specifies limits of sizes, and tolerances, for single start parallel screw threads of Whitworth form, for general engineering use.

While Whitworth threads have remained unchanged since the last revision of BS 84 in 1956, the present revision of the Standard has been undertaken on the basis that Whitworth threads will undoubtedly continue to be used for many years, especially on replacements or spare parts.

This standard specifies the following thread series:

a) a coarse thread series, the British Standard Whitworth (B.S.W.) series, with nominal diameters in the range 1/8 in to 6 in.
b) a fine thread series, the British Standard fine (B.S.F.) series, with nominal diameters in the range 3/16 in to 4 1/4 in.
c) a supplementary selected thread (WHIT. S.) series with nominal diameters from 1/4 in to 7 in.
d) a truncated Whitworth form series.

BS 84:2007 contains:

• Normative reference
• Terms, definitions and symbols
• Profile of Whitworth screw thread
• Tolerance classes of external and internal thread
• Limits of sizes, and tolerances, for uncoated B.S.W. and B.S.F. threads
• Limits of sizes, and tolerances, for B.S.W. and B.S.F. coated threads
• Stainless steel external threads
• Selected thread series
• Designation of screw threads of Whitworth form
• Gauges

This British Standard is intended for use with BS 919-2, which specifies the corresponding screw gauges.

BS 84:2007 replaces BS 84:1956, which is withdrawn.


<H2 class=tabName>Bibliographic Detail</H2>Standard NumberBS 84:2007TitleParallel screw threads of Whitworth form. RequirementsStatusCurrentPublication Date30 November 2007Cross References<A href="http://www.bsigroup....?q=BS 919-2">BS 919-2, BS 6528:1984, BS 1157, BS 1916-2, BS 6528ReplacesBS 84:1956DescriptorsWhitworth screw threads, Threads, Parallel threads, Thread forms, Thread pitch, Diameter, Nuts, Bolts, Dimensions, Metal coatings, Designations, Dimensional tolerances, Fits, Medium threads, Normal threads, Close-fit threads, Free threadsICS21.040.20 (Inch screw threads)
Title in FrenchFilets de vis paralleles de forme Whitworth. SpecificationTitle in GermanZylindrische Schraubgewinde vom Typ Whitworth. SpezifikationCommitteeFME/9ISBN978 0 580 57923 3PublisherBSIFormatA4DeliveryYESPages66File Size627 KBPrice£ 168.00

[MRA]

Oh by the way I never mention BSF as I unlike all the internet wizards above know that BSF is a totally different pitch. An expert is someone who doesn't stop learning, but it appears I was wrong and there aren't any on here !

I think you may want to read your own posts more carefully ?

BSF is not a different pitch, if you look you will find several corresponding pitches for both Whit, UN and BSF. We are capable of making mistakes including you.... At the moment you may feel that you have proven beyond all doubt that the crank thread is Whit 16tpi, which is certainly NOT Whit fine.... but as far as I am concerned until I get my results back from analysis nothing has been proven. As I said earlier how old are the drawings that everyone has ? Has the thread changed on later cranks ? Until I see my results nothing is set in stone, however if I am wrong then I'm wrong and like a lot of other Forum users I can admit I am wrong and get the right information on this forum. Can you ? or are you still going yo insist on calling Whit S by its incorrect name of Whit Fine ??

[Dan]

A "J" type UN thread form is what is known as a "controlled" root radius not specifically for Aerospace use

Not in actual use no but my understanding is that both UNR and UNJ were created for aerospace originally. If not where are they from?

[MRA]

A "J" type UN thread form is what is known as a "controlled" root radius not specifically for Aerospace use

Not in actual use no but my understanding is that both UNR and UNJ were created for aerospace originally. If not where are they from?

Hi Dan,

They are in use today, yes originally for aerospace use still used in the aerospace industry, Dassault, Boeing, etc etc. I use them on a regular basis, specifically 7/16" UNJF for HD tie bars,

I roll most of my thread forms either male or female, they have a controlled thread form as standard.

[Dan]

Sorry, badly phrased. All I meant was that they aren't limited to aerospace in use, not that they aren't in use at all.

I thought UNJ was for internal threads and UNR was for external. Is it the other way around?

[Nightrain]

Can save you the time waiting mra, like I said earlier the thread hasn't changed !

[MRA]

Sorry, badly phrased. All I meant was that they aren't limited to aerospace in use, not that they aren't in use at all.

I thought UNJ was for internal threads and UNR was for external. Is it the other way around?

Hi Dan,

UNJ can be either male or female, UNR is only Male.

[Guess-Works.com]

So now we come full circle and your adding MG's to my list, this is really sad you weren't around at the time none of us where and because it doesn't refer to a Whitworth Fine Thread on the internet it can't of existed. I can see I have put a lot of noses out of place. First off it wasn't a whitworth thread then after you've heard from a few people with more expertise than yourselves you all change your mind.
What a *melonsing* Joke.

Oh by the way I never mention BSF as I unlike all the internet wizards above know that BSF is a totally different pitch. An expert is someone who doesn't stop learning, but it appears I was wrong and there aren't any on here !

I can't see what you're getting so worked up about... I don't think that there's anyone refuting the evidence which you initially highlighted, and has been substantiated by original drawings etc. Obviously there was some scepticism initially, that would be natural... but quite a lot of that revolved about the use of a phrase which does not exist as a recognised thread, if you had copied the 'exact' text from the manual rather than paraphrasing we probably would not be in this position now.

A lot of people are now a little wiser with their new found knowledge, maybe it's time for others to be a little more humble in their Ivory Tower ?

[DaveRob]

Got to agree totally with Guessworks here.......... as for the statement

Oh by the way I never mention BSF as I unlike all the internet wizards above know that BSF is a totally different pitch

what is 16TPI if not a totally different pitch even when it Whitworth form..... Their is no British Standard specifiying WF at ANY pitch.... plenty saying what Whitworth, BSF, UNF,UNC etc etc and all easily available for all to examine. BMC/Rover/Leyland..... whoever.... it doesnt matter.... who.... decided to use a non standard thread for reasons we will never know...... but at least we have got to the bottom of it, and like I said, thanks for, highlighting the fact that it isnt a UN form but a Whitworth form..... all power to you for that one..........

Personally I feel its time to move on.......

Questions to be asked or answered ....for me anyways....

1. Are we all in agreemnt that the evidence points to the crank thread at both ends being 5/8th Whitworth form 16TPI

2. Can we source a tap to chase threads at reasonable cost in some sort of bulk buy deal..... Im guessing its going to be a plug or at worst 2nd tap as I cant see the point of a first tap, I wouldnt have thought anyone is going to cut a completly new thread.

3. Can Dan advise the responses re the suppliers thing please, when they materialise....... as you know Im particularly interested in the MED situation.

4. Any other business.

Thaks for the education here...... cant say its been a joy...... just educational....... lol

Rob

Edited by DaveRob, 31 March 2009 - 08:04 AM.

[Guess-Works.com]

Any taps I get made will be a 2nd, I'm not sure a plug (3rd) would be able to cut a rolled over thread which usually happens when an incorrect puller is used.

Edited by GuessWorks.co.uk, 31 March 2009 - 08:11 AM.

[DaveRob]

[Guess-Works.com]

Not often I post links to other forums....

http://www.minifinit...e...94&p=724920

[[email protected]]

After Dan PM'd me yesterday, my bolt supplier put all of the crank bolts, flywheel and crank pulley on a shadowgraph. All of these have, and always will be 5/8 x 16TPI. This is one of the OE suppliers into, BMC/Rover etc, what he doesn't know on this subject isn't worth knowing. He confirmed also that he recognises whitworth fine, as BSF.
As this would only have 14 TPI, claiming that whitworth fine is used is wrong, as it has the wrong thread count, as shown earlier in the thread.
So, a whitworth thread was used, but it cannot be classed as whitworth fine.