Author Topic: Old Screw Plate  (Read 8266 times)

Offline Meldonmech

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Old Screw Plate
« on: May 17, 2013, 03:18:45 AM »
Hi Guys,
                 I have this screw plate stamped Buck & Hickman 1892. The threads are numbered  1 smallest to 9.  The left hand threads are decimal marked from .094 to .25. The threads on the right are the same size but have numbers marked which are not  sequential, top to bottom :57, 49, 42, 37, 37, 50, 26, 33, 20, may be tpi ? Can anyone provide further information regarding the identity of these threads.

                                                                 Cheers David

Offline Pete W.

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Re: Old Screw Plate
« Reply #1 on: May 17, 2013, 04:08:12 AM »
Hi there, David,

I have just had a quick look in my 1971/72 edition of the Buck and Hickman catalogue (the last hard-back version before they went paperback).  Sadly, I have to report that I couldn't find any mention of your screw plate there.
Best regards,

Pete W.

If you can keep your head when all about you are losing theirs, you haven't seen the latest design change-note!

Offline vtsteam

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Re: Old Screw Plate
« Reply #2 on: May 17, 2013, 09:23:07 AM »
You could try running some soft wire through it and gauging the resulting threads to confirm TPI.
I love it when a Plan B comes together!
Steve
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Offline mattinker

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Re: Old Screw Plate
« Reply #3 on: May 17, 2013, 10:13:32 AM »
I don't know if this is of any help:-

http://en.wikipedia.org/wiki/Screw_thread#History_of_standardization

Regards, Matthew

Offline Lew_Merrick_PE

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Re: Old Screw Plate
« Reply #4 on: May 17, 2013, 11:21:27 AM »
David,

Inch-based screwthreads were not really standardized until WWI when the American-British-Canadian Joint Industrialization Committee (ABC) laid down the foundations for what became the Unified National thread standards.  (As a comparison, it was not until 1999 that a complete set of compatible standards for metric thread major-diameter & pitch specifications were written -- and there are still five separate and incompatible sets of tolerance & allowance "standards" accepted under the ISO specifications today.)  The "problem" is that, in 1892, what "standards" existed varied by industry.

Offline awemawson

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Re: Old Screw Plate
« Reply #5 on: May 17, 2013, 12:13:54 PM »
Not sure that Joseph Whitworth would be very happy with that statement:

"In 1841 Whitworth devised a standard for screw threads with a fixed thread angle of 55 and having a standard pitch for a given diameter. This soon became the first nationally standardized system; its adoption by the railway companies, who until then had all used different screw threads, leading to its widespread acceptance. It later became a British Standard, "British Standard Whitworth", abbreviated to BSW and governed by BS 84:1956."

(Source http://en.wikipedia.org/wiki/Joseph_Whitworth)
Andrew Mawson
East Sussex

Offline mattinker

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Re: Old Screw Plate
« Reply #6 on: May 17, 2013, 01:39:37 PM »
Or going a bit further!

 In 1841, Joseph Whitworth created a design that, through its adoption by many British railroad companies, became a national standard for the United Kingdom called British Standard Whitworth. During the 1840s through 1860s, this standard was often used in the United States and Canada as well, in addition to myriad intra- and inter-company standards. In April 1864, William Sellers presented a paper to the Franklin Institute in Philadelphia, proposing a new standard to replace the U.S.'s poorly standardized screw thread practice. Sellers simplified the Whitworth design by adopting a thread profile of 60 and a flattened tip (in contrast to Whitworth's 55 angle and rounded tip).[12][13] The 60 angle was already in common use in America,[14] but Sellers's system promised to make it and all other details of threadform consistent.

http://en.wikipedia.org/wiki/Screw_thread#History_of_standardization

Rob.Wilson

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Re: Old Screw Plate
« Reply #7 on: May 17, 2013, 04:18:28 PM »
Going back a tad further

Henry Maudslay actually came up with the first standardised screw threads , Whitworth worked at Maudslays works at the time when Maudslay was developing the standardised  screw threads  and help in its development , Whitworth put the finishing touches to the system , which became BSW.


Rob   

Offline Pete W.

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Re: Old Screw Plate
« Reply #8 on: May 17, 2013, 04:43:13 PM »
Hi all,

As a sequel (Horrible History!): 

Joseph Whitworth had two sons, Fred and Pete.

Fred wasn't very strong and couldn't turn a BSW tap wrench or die holder so he thought up a finer thread standard.  This is known, in his honour, as British Standard Fred or BSF.

Pete was into plumbing and produced a pipe thread standard which, in his honour, is referred-to as BSP.

Pipes in those days were specified by their bore and the pipe making process wasn't very good, so the pipes had quite thick walls.  For example, a 1_1/2" bore pipe had an external diameter of 1_29/32".  Later on, pipe making techniques improved and the wall thickness could be reduced without loss of strength.  However, the BSP threads meant that the OD couldn't be reduced without scrapping a lot of tooling so they increased the bore instead.  That's why you can't find any part of a 1_1/2" pipe that actually measures 1_1/2"!!!

 :D   :D   :D   :D   :D   :D   :D   :D   :D 
Best regards,

Pete W.

If you can keep your head when all about you are losing theirs, you haven't seen the latest design change-note!

Offline vtsteam

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Re: Old Screw Plate
« Reply #9 on: May 17, 2013, 09:17:02 PM »
I'm going to take a stab at it -- pure guesswork -- and suggest that it is an early BA thread --  but prior to standardization in 1903. I think the sizes are a therefore a little arbitrary but I'm guessing the maker made them compatible with Birmingham / Stubs wire gauges eg the first screw die takes a 13GA --  I'm not sure about the consecutive numbers because they don't match with wire gauges but that could just be a simple identification.
I love it when a Plan B comes together!
Steve
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Offline Lew_Merrick_PE

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Re: Old Screw Plate
« Reply #10 on: May 18, 2013, 02:07:27 AM »
In 1841, Joseph Whitworth created a design that, through its adoption by many British railroad companies, became a national standard for the United Kingdom called British Standard Whitworth.

1) If you have read my treatise on the history of screwthreads (I bailed on ScribD when they started claiming copyright on anything posted there), you will know that I understand Joseph Whitworth's contributions quite well.  However, prior to WWI, the Whitworth thread was an industry standard rather than a national standard(Actually, standardization of the Whitworth thread was one of the things that came out of the breast-beating after the end of the Boer War.  In point of fact, the "push" to authorize the ABC Joint Industrialization effort for WWI came about to avoid some of the nasty failures encountered during the Boer War.)

2) The first really successful attempt to create a standardized screwthread was Ernst Lowenhertz's system developed in Prussia in the 1760's.  In point of fact, Eli Whitney used a set of taps & dies he stole from Lowenhertz when he made his famous demonstration of interchangeability to the (American) Continental Congress in 1798.  Lowenhertz used 5345' as the male thread included angle in an attempt to equalize screw & nut threads.  Whitworth simplified that to 55, but the  interaction was not really understood until after Simeon Poisson's seminal work on stress/strain distribution.

The truth is that Whitworth's real contribution was recognizing that allowances & tolerances were really dependent on the circumferential length of the pitch diameter about the helix of the thread.
« Last Edit: May 18, 2013, 12:10:04 PM by Lew_Merrick_PE »

Offline Fergus OMore

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Re: Old Screw Plate
« Reply #11 on: May 18, 2013, 03:14:39 AM »
As far as we have it, Buck and Hickman only started in 1830.
The screw plate is far earlier than that. Charles Holzapffel illustrates the tool and goes on to wisely conclude that diestocks , in common with other  general tools, has received a great many modifications that it would be useless to trace in greater detail.

Oddly I have a slightly more modern version which hangs -with my screwing tackle- pronounced 'Take-ell' in Armstrong Whitworth country.  Mine is 'Coarse Whitworth' of course.

Rob.Wilson

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Re: Old Screw Plate
« Reply #12 on: May 18, 2013, 03:19:18 AM »
Quote
He proceeded to dilate upon the importance of the uniformity of screws .Some may call it an improvement,but it might almost be called a revolution in mechanical engineering which Mr Maudslay introduced . Before his time no system had been followed in proportioning the number of threads of a screw to the diameter.

James Nasmyth Engineer an Autobiography 1883 .   



A bit more info web based . http://www.thefullwiki.org/Screw_thread scroll to "History of standardization."


Any chance of a copy of your  "treatise on the history of screwthreads"  Lew




Rob
« Last Edit: May 18, 2013, 05:23:09 AM by RobWilson »

Offline Meldonmech

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Re: Old Screw Plate
« Reply #13 on: May 18, 2013, 09:35:50 AM »
Hi Guys,
              Thanks for all your replies, I never expected such a wonderful response.
               Pete, I have come across many threads in the past but have never met Fred.
               Rob, that looks a nice book is it yours, or are you down at the library?
               
                                                   Cheers David

Rob.Wilson

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Re: Old Screw Plate
« Reply #14 on: May 18, 2013, 10:11:50 AM »

               Rob, that looks a nice book is it yours, or are you down at the library?
               
                                                   Cheers David

Hi David

The book is mine .


One from my own personal library , I have a good few books on engineering related subjects from the 1800s . Books were far better made then .

Rob

Offline Pete W.

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Re: Old Screw Plate
« Reply #15 on: May 18, 2013, 10:52:30 AM »
Hi Guys,
              SNIP
               Pete, I have come across many threads in the past but have never met Fred.
               Rob, that looks a nice book is it yours, or are you down at the library?
               
                                                   Cheers David

Hi there, David,

I was a bit worried (after I pressed 'Post') that my light-hearted contribution might be viewed as 'lowering the tone of the place'!   :doh:   :doh:

I do feel, though, that the business about 'where on a 1_1/2" pipe can you actually measure 1_1/2"' does deserve explanation every so often.  I share your admiration for Rob's library.  I don't have mechanical engineering books that old.

This thread seems to have taken a direction that's interesting but that doesn't answer your initial post.
Best regards,

Pete W.

If you can keep your head when all about you are losing theirs, you haven't seen the latest design change-note!

Offline Lew_Merrick_PE

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Re: Old Screw Plate
« Reply #16 on: May 18, 2013, 12:30:43 PM »
Any chance of a copy of your  "treatise on the history of screwthreads"  Lew

Yes, please remind me in about two weeks (tangent@olympus.net) and I will reload my "handbook files" (that were removed from my system for a design project the requires a "clean and empty of other work" drive) and post it.

Poor Ernst Lowenhertz (umlaut-o missing) was really the only person who could have challenged Ben Franklin as greatest practical scientist of the 18th century.  Unfortunately, the NAZI's adopted him as a demi-god and he has been removed from history for the most part.  I worked a project back in the 1970's where the document control officer was a West Point military engineering historian.  I got to read (facsimiles, of course) of British and later American intelligence reports on his work in Prussia.  He came to the attention of "intelligence" during the Seven Year's War (known in America as the French and Indian War).  It was really quite entertaining.

Rob.Wilson

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Re: Old Screw Plate
« Reply #17 on: May 18, 2013, 02:44:34 PM »
Hi Pete

Nothing wrong with making the point about BSP threads  :thumbup:   , your right though this THREAD has wandered , may be its a drunken thread  :lol:


Rob

Offline tekfab

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Re: Old Screw Plate
« Reply #18 on: May 18, 2013, 03:56:20 PM »
Hi Pete

, your right though this THREAD has wandered , may be its a drunken thread  :lol:


Rob

Or a crossed thread ?