The Kent History Forum

Industry => Mills => Topic started by: Smiffy on May 17, 2020, 01:17:04 AM

Title: Windmill sweeps
Post by: Smiffy on May 17, 2020, 01:17:04 AM
Most windmills seem to be set so that their sweeps rotate anti-clockwise. Is there a specific reason for this, or is it just convention?
Title: Re: Windmill sweeps
Post by: castle261 on May 17, 2020, 09:30:36 AM
I have made two windmills, one Tower, one Post -- the Post one I tested in the garden, in a wind.
The sweeps/vanes flew round so fast, all the sweeps/vanes, came of as one. Mine was to do
with the screw thread in the centre, holding it on. -- Mine went anti clockwise. It un- screwed - itself.
Needed a --------- locking nut. -- Both windmills over three feet tall - to top of sweeps/vanes.
Title: Re: Windmill sweeps
Post by: Smiffy on May 17, 2020, 01:44:39 PM
Have you got any photo's of them we can look at?
Title: Re: Windmill sweeps
Post by: grandarog on May 17, 2020, 02:05:58 PM
I have also made 2 Windmills.Both with fixed Cowls.
The first was in our previous back garden .When we moved I left it for the new owners as they loved it.
The second I built here on our front lawn.
I have never had any trouble with sweeps coming adrift.
They were mounted on one end of a Bicycle wheel hub.
I also built 2 Water Mills but that's off topic.
Title: Re: Windmill sweeps
Post by: MartinR on May 17, 2020, 02:38:48 PM
Windmill sweeps may appear to go around anti-clockwise from one point of view (the "front"), but from elsewhere, particularly inside the mill, they are going clockwise.
Just speculating, but if the sweeps go clockwise (viewed from within the mill), the brake wheel is of course going CW so the wallower will be going ACW (viewed from above).  Therefore the great spur wheel will be doing ACW, and so the stone nuts will be going CW.  There is usually a preference for the stones to rotate CW, if they went widdershins the flour would be of bad quality!  More prosaically, the stones were "bought in" and I'm guessing would always be cut for CW milling.  All suposition of course!
Title: Re: Windmill sweeps
Post by: Smiffy on May 17, 2020, 09:08:38 PM
Yes, I meant viewed from the front. Bertroid may have a definitive answer to this when he next logs on.

grandarog, that's really charming - much better viewing than an army of gnomes!
Title: Re: Windmill sweeps
Post by: bertroid on May 18, 2020, 06:00:32 PM
Windmill sweeps may appear to go around anti-clockwise from one point of view (the "front"), but from elsewhere, particularly inside the mill, they are going clockwise.
Just speculating, but if the sweeps go clockwise (viewed from within the mill), the brake wheel is of course going CW so the wallower will be going ACW (viewed from above).  Therefore the great spur wheel will be doing ACW, and so the stone nuts will be going CW.  There is usually a preference for the stones to rotate CW, if they went widdershins the flour would be of bad quality!  More prosaically, the stones were "bought in" and I'm guessing would always be cut for CW milling.  All suposition of course!


Apologies for not seeing this earlier, but no one normally posts on the mills bit!


Supposedly in modern times, wind turbines turn clockwise these days, due to the efficiency and the earth's gravitational pull, but yes, most mills were built anti-clockwise, and I'm not aware of any mills in Kent ever being clockwise. In East Anglia and the Midlands there are/were quite a few clockwise mills built, and a handful in Sussex.


As for gearing turning in the opposite direction, it doesn't make any difference to ground flour quality, but as Martin R states, millstones were often supplied pre-dressed anti-clockwise, so it became a convention, especially with journeymen millstone dressers who were used to dressing/cutting the stones that way when they needed re-dressing.  As an aside, the phrase 'show me your hands' is alleged to relate to millstone dressers and their experience, as the darker the hands (through flecks of stone) the more experienced the dresser.


For me the most interesting point is that areas were full of journeymen millers, and you'd know which way the sails were coming from if you walked out the door!
Title: Re: Windmill sweeps
Post by: Smiffy on May 18, 2020, 06:28:41 PM
Do we know which way Dutch windmill sweeps rotate? If clockwise, perhaps this is a legacy that was left over from their use in East Anglian Fenland drainage.
Title: Re: Windmill sweeps
Post by: bertroid on May 18, 2020, 07:05:56 PM
Do we know which way Dutch windmill sweeps rotate? If clockwise, perhaps this is a legacy that was left over from their use in East Anglian Fenland drainage.


That would make sense for the Eastern England thing, but the Dutch have a similar ratio to us over here, which would be roughly 75% - 25% in favour of anti-clockwise.

Title: Re: Windmill sweeps
Post by: MartinR on May 18, 2020, 07:10:31 PM
The reference to turning widdershins was not serious, it refers back to ancient superstition.  Just like if you stir wort widdershins the beer is reputed to be bad.  Because you are going against the way of the sun it invites the Prince of Darkness to play his tricks.  Got to frighten the children. ;D ;D ;D