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Old 14th Feb 2018, 8:13 pm   #1
GrimJosef
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Default Film of Erie Type 8 resistor manufacture

By chance I've discovered that the Imperial War Museum holds a copy of a film made in 1970 showing some of the details of the manufacture of Erie Type 8 resistors - the familiar ceramic bodied carbon composition ones. The IWM's description of the film is here https://www.iwm.org.uk/collections/i...ect/1060039091.

Has anyone seen this film and, if you have, can you remember what was in it ? I'm curious to see it so I've contacted the IWM. They've been very helpful but they haven't yet digitised the 16mm original, of which I think they have just one copy. They're prepared to digitise it and let me have an electronic copy for 40+VAT but if they do then I have to promise that it will be for my personal use only. They tell me that I can show it to other people who might be interested but that if anyone else wants their own copy then they'll have to buy one from the IWM. I could also arrange to post the film online but if I did then there would be a 'per second' fee payable (I've asked how much that might be but haven't heard back yet).

Cheers,

GJ
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Old 20th Apr 2018, 6:27 pm   #2
GrimJosef
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Default Re: Film of Erie Type 8 resistor manufacture

Well I heard back from the IWM today and I've now seen a digitised copy of this film. I don't believe it's from 1970 at all. The manufacturing techniques and the whole 'atmosphere' feel much more like the 1940's. And in fact the credits show that the film was made by Douglas Fisher. This website http://www.radararchive.com/, set up by his son, indicates that he was working at the Telecommunications Research Establishment, whose name is also on the film, during WWII and that he moved to Burroughs Wellcome after the war.

The film doesn't go into any real detail about the resistors themselves. But it does show them being put together, painted, tested and packed. The working techniques and conditions are really rather primitive. The film is silent with captions but, surprisingly perhaps, is in Kodachrome colour.

Cheers,

GJ
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Old 23rd Apr 2018, 10:38 am   #3
GrimJosef
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Default Re: Film of Erie Type 8 resistor manufacture

Well things have moved on and I've now learnt a bit more about IWM's position on their copyright film material. Long story short: they don't have enough resource to digitise all of it, but if someone requests access to a particular film then they may be able to digitise that. If they do digitise it, however, they then have to recognise that the film was actually public property and the fact that they are looking after it doesn't change that. As a consequence when they can they are obliged to make it freely and publicly available. So the film is now live on their website and you can watch it for free there if you're interested. You just have to click on the 'play' symbol in the link in my first post. Enjoy !

Cheers,

GJ
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Old 23rd Apr 2018, 11:48 am   #4
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Default Re: Film of Erie Type 8 resistor manufacture

Thank you so much for organising this. Although it doesn't give away any secrets about the all-important composition slug, it's fun and it just possibly solves a puzzle. As I've mentioned before, the Compton electrostatic organs that I collect use a very large number of Erie resistors, typically between three and five thousand per instrument, many of which are in the 1M decade. With such a large sample, and many identical resistors used in identical circuit positions, trends emerge that would be missed when dealing with a dozen or two in a radio or TV where very few stages are electrically similar.

One such oddity is that 5M0 parts (a value specified by Compton as a step in their 2dB voicing series) are more prone to serious upward drift than other nearby values; many have reached 10MΩ or more today. If these were originally selected from the 4M7 bin and re-marked as shown in the film, we are dealing with resistors that were skewed 6% high during manufacture and then subjected to vigorous agitation after the impregnation stage, which may have affected their long-term environmental protection, microscopic structure and-or lead-to-slug contact resistance. This may not be the correct explanation as most of my examples are of later manufacture with 3-band marking, but I seem to recall the behaviour does apply equally to body-tip-dot and 3-band examples. It would be interesting to know just how the bell curve of finished product tolerance was distorted by such methods, before they reached the shelves.

I'd agree that the film is earlier than 1970. I would have put it at mid 1950s; perhaps more clues will emerge during further viewings.

Note 5M0 parts lurking in this voicing matrix:
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Old 23rd Apr 2018, 11:59 am   #5
M0FYA Andy
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Default Re: Film of Erie Type 8 resistor manufacture

I would agree that this film looks to be 1950s. Quite fascinating!
Andy
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Old 23rd Apr 2018, 12:01 pm   #6
GrimJosef
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Default Re: Film of Erie Type 8 resistor manufacture

As far as the dating goes, Fisher's radararchive bio does seem to indicate that he was only at TRE during the war. Since he was a specialist film-maker I suppose it's possible that he was persuaded to go back and make this short at some later stage. But my gut feeling is that it was made in the 40's, not least because the 3-band marking was already in production in the early 50's. I think I've actually got some of those small cardboard boxes with body-tip-ring resistors in them somewhere.

Incidentally I spoke to the IWM this morning and I have to say they've been very helpful. If you can identify films in their collection which might be interesting then they are inclined to digitise them if they can. They were at pains to point out that they can't promise anything - their resources are limited and they can be very busy at times. But at the moment things aren't too bad and they can get films done.

Cheers,

GJ
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Old 23rd Apr 2018, 12:44 pm   #7
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Default Re: Film of Erie Type 8 resistor manufacture

The resistors being made all have the old style all-over coloured body for the first value digit, rather than a natural white body with completely separate bands.
I think this also dates it well before 1970, and more like 1940's...anyone have more accurate idea when that changed?

Pete
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Old 23rd Apr 2018, 3:57 pm   #8
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Default Re: Film of Erie Type 8 resistor manufacture

"ERIE RESISTORS
A T.R.E. FILM in Kodachrome
"

T.R.E. in the film's title dates it to between November 1940 and 1953. According to Wikipedia:
"The development of radar in the United Kingdom was started by Sir Henry Tizard's Committee for the Scientific Survey of Air Defence in 1935. Experimental work was begun at Orfordness near Ipswich. The research group moved to the nearby Bawdsey Research Station (BRS) in 1936. It moved from there to the University College at Dundee in 1939 as the Air Ministry Research Establishment (AMRE). Then, in May 1940, it moved to Worth Matravers as the Ministry of Aircraft Production Research Establishment (MAPRE). It was established as the central research group for RAF applications of radar. The name was changed to the Telecommunications Research Establishment (TRE) in November 1940."

"Telecommunications Research Establishment (TRE) was the main United Kingdom research and development organization for radio navigation, radar, infra-red detection for heat seeking missiles, and related work for the Royal Air Force (RAF) during World War II and the years that followed. The name was changed to Radar Research Establishment in 1953."
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Old 23rd Apr 2018, 4:06 pm   #9
GrimJosef
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Default Re: Film of Erie Type 8 resistor manufacture

As far as production dates for the resistor types go, I have some type 9 Erie resistors in original cardboard boxes, a very few of which have date stamps. The boxes are not sealed though, and they came from a university lab, so I can't guarantee that they haven't been 'topped up' over the years.

The stamp legibility is poor but the attached picture shows what are, perhaps, the best two. The 7k6 resistors in the box dated 6 DEC 1944 are an unusual value so perhaps it's more likely that they were the ones which were originally supplied in that box ? They're 3-band with a khaki body colour. The other box is dated 14 JUN 194? (the last digit is unclear, but could be a 3 or a 5). It was for 12R resistors and there is indeed a mix of them in it - all 3-band with some on a khaki background and some on an off-white one.

Cheers,

GJ
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Old 23rd Apr 2018, 5:54 pm   #10
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Default Re: Film of Erie Type 8 resistor manufacture

the guy in the packing department had a rather snazzy hairdo if that dates it any better!
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Old 23rd Apr 2018, 6:19 pm   #11
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Default Re: Film of Erie Type 8 resistor manufacture

I think it might have been a female operative Kevin.

Snazzy hairdo's and long hair for men were about 20 years away when this film was shot, and then they would have to wear hairnets/snoods to keep their hair out of the machinery!

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Old 23rd Apr 2018, 6:21 pm   #12
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Default Re: Film of Erie Type 8 resistor manufacture

Tricky nailing the date of that production- never before have so few obvious clues been given- not even the captions give the slightest hint.

The box for my hi-stab (1W) Eries is a different style, with red print on the label but still very low grade cardboard. As NOS items they have kept very well- Seven 680k's (1% tol) are only high by a mean value of 0.6% and a maximum of 1.3%. Four of the seven are within 0.4%.
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Old 23rd Apr 2018, 6:31 pm   #13
GrimJosef
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Default Re: Film of Erie Type 8 resistor manufacture

High-stab Eries behave wonderfully. They look similar to the carbon comps from the outside (very slightly different sizes) but they are entirely different internally. The resistive element is a carbon film which is completely stable. It is also less electrically noisy. They were more expensive to make though than the carbon comps. And they wouldn't stand pulsed overload in the way the comps would.

I've been in touch with Douglas Fisher's son through the radararchive website and he's confirmed that his father was at TRE only during the war. He thinks he never returned, not even briefly. So the film would certainly have been made in the first half of the 1940's. His son remembers Douglas (his grandfather) telling him that there was a significant issue with designers ordering up non-standard resistor values and that they tried to explain to them how expensive and time-consuming this was. Maybe the point of the film, at least in part, was to drive this home ?

Cheers,

GJ
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Old 23rd Apr 2018, 7:37 pm   #14
M0FYA Andy
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Default Re: Film of Erie Type 8 resistor manufacture

I was doubting that effort would have been devoted during the war years to make such a film, but it makes sense if a message had to be got across to the equipment designers.
It does seem astonishing that the best way to produce a batch of 5K resistors was to select from 4.7K, clean all the markings off and repaint them!
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