The manufacture of high-precision brass telescope tubes 1780 to 1990

This episode in our Vintage Telescopes Masterclass series looks at the method employed in Britain for the manufacture of precision brass telescope tubes from the latter half of the 18th century until the closing decade of the 20th. Much has been written about the instrument makers of the 18th and 19th century and the design and construction of the optical glassware employed in their telescopes. But the methods employed in the manufacture the brass tubes and other parts so vital to the positioning and adjustment of the optics has received much less attention.

The volume production of high precision brass instrument tubing played an important role in the development of telescopes and microscopes after 1780. In this video Robert looks at the history of the drawing method used for precision brass tube production with the aid of some unique footage shot in 1990 to demonstrate the tube drawing method and apparatus used by Broadhurst Clakson & Fuller Ltd, (a commercial descendant of Broadhurst Clarkson & Co Ltd [BC&Co ltd]) believed to be the last instrument maker in England still able to produce tubing in this long established manner.

0:20 Opening remarks
2:01 Brass tube drawing’s relation to older wire drawing method
4:11 Where the footage was recorded
5:20 The compromised quality of the material recorded in 1990
7:52 The Gerry Morris show - the demonstration begins
37:44 Rememberance and concluding remarks
40:11 Further reading

Erratum

At 36:20 Dudley Fuller suggests that the large engine powered drawing machine has been situated in the basement workshop since 1830. This is not the case and is a minor slip of the tongue on Dudley’s part – easily done given that he is filming and narrating at the same time - as Robert H Broadhurst’s company (BC&Co Ltd) only took up residency at 63 Farringdon Road sometime after 1906. He may have meant to say that the machine had been in its current location from around 1920 to 1930. However, there is some evidence that the machine may date from the mid-19th century – perhaps as early as 1830 – and he may have been trying to recall this fact. Indeed it is difficult to image how the company would have managed to keep up with the demand due to the first world war (1914-1918) armed only with the hand drawing machine. It is quite likely that Dennis Broadhurst passed information relating to the machine’s origin to Dudley when negotiating the sale of the company in 1973. So Dudley may have had in mind the powered drawing machines’ physical arrival in the basement workshop at Farringdon Rd in 1930 having been moved from another workshop operated by BC&Co at Fenchurch Street and simply fluffed the century or he may have been referring to 1830 as a point of origin for the machine when it was in the hands of others associated with the history of BC&Co Ltd confusing the location rather than the date. We may never know the truth. If YOU have any information that might help us to date the arrival of the engine draw bench in the Farringdon Rd workshop then please drop us a line.

Presented by Robert J. Dalby FRAS

Our thanks to
David Lawrence - MD Broadhurst Clarkson & Fuller Ltd
Steve Collingwood - Broadhurst Clarkson & Fuller Ltd
Ian Docherty - Broadhurst Clarkson & Fuller Ltd
for assistance and support

Dr Allan Mills, University of Leicester (emeritus)
for permission to use a draft manuscript of his paper
‘The Manufacture of Precision Brass Tubing’
published in the Bulletin of the Scientific Instrument Society No 27 (1990)

Richard Day, Skylight Telescopes
for the obit photo of Gerald Morris

Видео The manufacture of high-precision brass telescope tubes 1780 to 1990 канала Astronomy and Nature TV