I asked a colleague in the Midlands Mills group about this. He pointed to
his own booklet on Warwickshire watermills, which reproduces the same
illustration. This in turn enabled me to see a reproduction of the original
(and associated text) in Desaguliers, J. T. (John Theophilus). A course of
experimental philosophy. By J. T. Desaguliers, ... The third edition
corrected. London, 1763. 627pp. Vol. 2 of 2 (2 vols. available): plate in
vol II opposite p.452. I accessed this via 18th century collections
on-line, which requires an Athens (or other) log in, so that I will not give
a web address.
The mill illustrated would now be known as Nuneaton Mill in north
Warwickshire. He said that this is merely the first illustration of
multiple stone nuts. He believes there are earlier examples. It was an
invention, but nobody is certain quite when.
49, Stourbridge Road,
[log in to unmask]
From: Arch-Metals Group [mailto:[log in to unmask]]On Behalf Of
Lyle E. Browning
Sent: 30 October 2008 23:41
To: [log in to unmask]
Subject: Re: Hybrid gears
On Oct 30, 2008, at 5:07 PM, Peter King wrote:
> My colleagues in the Midland Mills Group (mostly interested in corn
> regularly say that wooden teeth were preferred, even with metal
> because they were easily replaced. Mishandling the mill could
> easily strip
> several teeth, so that it was desirable to have something that could
> break and be replaced, thus preventing worse damage.
I've seen small pieces out of teeth, but in the main, the hybrid parts
are stacked up under the stone floor and the all-metal set-ups were
doing the actual work. But, that was before I was aware enough to
differentiate the stages and none that I saw had markings anyway.
> What is your 1723 reference? I had heard of the change to driving
> stonenuts off the same great spur wheel, but I had seen a source
> pinning the
> change down.
The 1969 "Transactions of the International Symposium on Molinology,
held in Denmark. Chapter 27 was on Great Britain and was entitled The
Water-powered Cornmills of England, Wales, and the Isle of Man, A
Preliminary Account of their Development by David H. Jones. In that,
page 311 has the relevant part. A 1723 drawing by Henry Beighton of
the mil at Barr Pool by the Abbey in Nunn Eaton, Warwickshire was
cited as the first to show spur gearing. The drawing, in the pub,
shows two sets of stones with one wheel. The two are powered off two
separate lantern/pinion sets. The author's take on it was that it was
referred to as something new and different.
> Peter King
> 49, Stourbridge Road,
> West Midlands
> DY9 0QS
> [log in to unmask]
> -----Original Message-----
> From: Arch-Metals Group [mailto:[log in to unmask]]On Behalf
> Lyle E. Browning
> Sent: 30 October 2008 16:00
> To: [log in to unmask]
> Subject: Hybrid gears
> Spur gearing is generally recognized as being invented in 1723
> allowing the 1 wheel to 1 device problem that had plagued mills from
> the get-go to disappear. There was a transitional hybrid period where
> the wheels were metal and the teeth were wood. Then it all moved to
> totally metal gearing.
> Was the transition from wooden lantern/pinion gearing to hybrid metal/
> wood to all metal a result of incremental steps from the familiar to
> the new a result of the then presumed inherent brittleness of cast
> iron or was it a stepwise progression based on the known and workable
> system? The problem was in if one bought a cast wheel with teeth and a
> tooth broke, you had to replace the entire wheel, so better to have
> wooden teeth that if one broke, then the tooth could be replaced. This
> was standard on wooden gear systems.
> Wooden transmissions used lantern/pinion systems. A secondary thought
> was that the move to metal started by using metal for the wheels as it
> was cheaper and more durable. Wood was used for the teeth because they
> had to mesh with the wooden lantern. Is this a reasonable supposition?
> In my surveys of gristmills, I see examples of hybrid wheels under the
> stone floor as they were replaced by all metal bevel gears, but which
> were kept for various reasons.
> At some point in the 19th century, the hybrids stopped and the all
> metal gears took over, at least here in VA and elsewhere in the US
> that I have managed to find info concerning. When do all metal bevel
> gears start?
> Were there advances in iron casting that would allow for all metal
> wheels with teeth and bevel gears to replace the hybrids?
> In short, can metallurgical advances be shown to parallel the
> transition from wood to hybrid to metal? Or are we looking at a
> conservative step-wise progression for which cast metals already
> existed that would work that the millers and other power applications
> were slow to adopt?
> Any thoughts gratefully received.
> Lyle Browning