A new screw thread & ION exchange resins

[martin perman 1Participant @martinperman1]

After reading the post "measurements of the past" I started reading a copy of Practical Mechanics July 1949, one of a few I picked up last October, and found two interesting pieces written by the editor under FAIR COMMENT.

The first piece is regarding "the new screw thread" this is the adoption of the new "Unified" thread form which had been ratified by the signing of the Declaration of Accord. The British Standards Institution issued a provisional specification of the thread series for use by industry.

The new thread came about because of interchangability between English and American threads during the last war.

Investigations of the new thread were carried out by the N.P.L engineering division mainly concernining its strength and it was found to be stronger than the Whitworth series. Tests were also made between the interchangeability of the two threads which showed no loss of strength between crossing parts between the two threads.

The other piece was the discovery,1934, of ION exchange resins by Holmes and Adams one class of these is synthetic resins which when ordinary tap water was passed through them the water quality changed in purity similar to distilled water and sea water when passed through them became drinkable.

This lead to the use of water softening use in the home and industry.

Martin P

[martin perman 1Participant @martinperman1]

[egaParticipant @ega]

Interesting.

Does this mean that, say, a 5/16" UNC screw in a 5/16" BSW hole will be as strong (or stronger) than a like for like pairing?

Judging by the impressive security fence outside the NPL, they must be doing some important work.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by ega on 03/01/2019 17:20:01:

Interesting.

Does this mean that, say, a 5/16" UNC screw in a 5/16" BSW hole will be as strong (or stronger) than a like for like pairing?

.

I would like to see the actual report … The editorial summary on interchangeability reads like utter tosh:

[quote]

Tests were also made between the interchangeability of the two threads which showed no loss of strength between crossing parts between the two threads.

[/quote]

MichaelG.

.

Edit: I've just searched, and found this:

https://apps.dtic.mil/dtic/tr/fulltext/u2/a280223.pdf

Not had chance to read it properly, but: There are only four occurrences of the word 'Whitworth' and they are associated with the word 'truncated'

I rest my case.

Edited By Michael Gilligan on 03/01/2019 18:00:14

[Michael GilliganParticipant @michaelgilligan61133]

Incidentally [and hoping that Martin has no objection] … here is a very neat single page summary of 'the more common standard series' threads, in our sort of sizes: **LINK**

http://www.kayelaby.npl.co.uk/miscellaneous_engineering_data/5_1/5_1.html

MichaelG.

[martin perman 1Participant @martinperman1]

No problem, I'm only pleased I writ what I red

Martin P

[Michael GilliganParticipant @michaelgilligan61133]

[Anonymous]

The idea behind the unified thread form was that it rationalised the US/Canadian threads and in the UK would replace Whitworth threads. Of course it didn't quite work out, but it was a sensible idea given the volume of armaments imported from the US during WWII.

Andrew

[martin perman 1Participant @martinperman1]

Posted by Andrew Johnston on 03/01/2019 21:15:26:

The idea behind the unified thread form was that it rationalised the US/Canadian threads and in the UK would replace Whitworth threads. Of course it didn't quite work out, but it was a sensible idea given the volume of armaments imported from the US during WWII.

Andrew

Surely that worked, not. Wasnt there a colaboration between us and them where we built a part in metric and they in english and nobody could understand why they wouldnt fit together.

Martin P

[not done it yetParticipant @notdoneityet]

Posted by martin perman on 03/01/2019 21:23:44

Surely that worked, not. Wasnt there a colaboration between us and them where we built a part in metric and they in english and nobody could understand why they wouldnt fit together.

Martin P

Nah! Likely we made Whitworth and they made UNC, but most threads were 1/2” in diameter!

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