ME Traction Engine Blueprint

I've been emptying boxes from our move last year and setting up my library of Model Engineer magazines. In one of the boxes I came across this blueprint of the original ME traction engine as designed by Henry Greenly. This was included with the issue for the 5th of January 1933. Mine was not with that issue, although I probably do have the issue somewhere. I am still sorting out some of the loose magazines from before the war. My collection is pretty complete from 1942 onwards, before that I have maybe a quarter of the issues going back to the first.

Anyway, I thought this might be of some interest, if only historic. I suspect it is not a real blueprint, although it is backed up with linen. I think it has probably been printed on paper by a normal printing process and then attached to the linen.

I also have another Greenly blueprint, even older, of his uniflow engine from 1923.

John

Edited By John Olsen on 30/10/2016 06:27:54

Edited By John Olsen on 30/10/2016 06:28:20

That makes me feel old, when I started work blueprints where still used.

It will be a real blueprint - much cheaper than printing for small runs in those days. It was not unusual to back them with linen.

Early drawings were drawn by hand on coated linen with ink pens and copies made by placing sensitised paper behind the original in a simple frame with a glass cover (like a picture frame) and exposing it to the sun. If it was a cloudy day you could not make prints. The exposed print then developed by placing it in a water/ammonia solution and then hung up to dry.

After O-levels, in the early 70s, I got a summer job at Texas Instruments in Bedford. Having been allocated to the accounts department I kicked up a fuss until I got moved to production. Occasionally I had to go to the drawing section to collect prints; I can still remember the smell of ammonia.

Andrew

I seem to think that blue prints used potassium ferrocyanide. The old "Dyeline" printing system which gave a positive print off tracing paper or polyester film did use ammonia. At my place of work this system was in general use well into the 1990s until CADs took over.

JA

Edited By JA on 30/10/2016 11:31:11

I worked in a place that used the ammonia process in the late 80s.

I did wonder about the health of the two chaps who spent every day in a small room with bright UV and the stench of ammonia all day!

Neil

It's a Cyanotype, invented by Sir John Herschel, polymath and astronomer, son of William. (I didn't know that but Wikipedia did )

Rod

That takes me back - there's nothing like the smell of print room ammonia for sorting out a morning hangover!

Steve

.... and the ubiquitous graffiti outside saying "some day my prints will come".