Post Mill
Built in 1789, dismanted in 1965 and now being restored.
In this picture it can be seen that the body has been removed from the post so that the post structure can be restored.
Post mills are so named because of the large upright post on which the mill's main structure (the "body" or "buck") is balanced. By mounting the body this way, the mill is able to rotate to face the (variable) wind direction.
To maintain the upright post, a structure consisting of horizontal crosstrees, and angled quarterbars is used. By far the most common arrangement was 2 cross bars at right angles to each other under the base of the post, together with 4 quarterbars. Occasionally however other arrangements did occur, such as 3 crosstrees, and consequently 6 quarterbars. The mill in this photograph is famous for having 3 crosstrees, and 6 quarterbars.
Initially the crosstrees would have rested directly on the ground, (or indeed were buried in the ground for extra stability) but since this makes them very succeptible to rotting, the crosstrees were soon being placed on brick piers to raise them off the ground (as can be clearly seen in this photograph).
The body of the mill housed all the milling machinery - a large brake wheel on the same shaft as the sails (the "windshaft") transferred power to a smaller gear at right angles to it, called the wallower. The wallower shared a vertical shaft with the great spur wheel, and from this smaller wheel a "stone nut" was used to drive the millstone. As larger mill bodies were constructed, additional pairs of stones could be driven, by taking further power taps, each using an extra "stone nut" off the great spur wheel. In order to apply some level of control to the mill, the brake wheel could be slowed using a large wooden friction brake around its outer edge.
As already mentioned, the whole body rotated on the central post, in order to face the wind. To allow this to happen, a tailpole or tiller beam extended from the rear of the body. By pushing on this beam (or by using some form of winch or animal power) the miller rotated his mill. The tailpole also provides a useful attachment point for a ladder to provide access to the mill.
An obvious improvement on the early post mill, is to build a roundhouse up around the crosstrees and quarterbar structure. This makes this structure a lot more protected from the weather, and provides additional storage space.
An interesting web site with a few more pics:
www.jrsaville.co.uk/chinnor.htm
A photograph of the mill in 1932:
viewfinder.english-heritage.org.uk/search/detail.aspx?uid...
Tags: Chinnor Oxfordshire Windmills Post Mills Panasonic Lumix TZ3 England UK United Kingdom © John Ward
© All Rights Reserved
Post Mill
Built in 1789, dismanted in 1965 and now being restored.
The body was removed from the post so that the post structure could be restored and here it is reinstated as it was meant to be.
Post mills are so named because of the large upright post on which the mill's main structure (the "body" or "buck") is balanced. By mounting the body this way, the mill is able to rotate to face the (variable) wind direction.
To maintain the upright post, a structure consisting of horizontal crosstrees, and angled quarterbars is used. By far the most common arrangement was 2 cross bars at right angles to each other under the base of the post, together with 4 quarterbars. Occasionally however other arrangements did occur, such as 3 crosstrees, and consequently 6 quarterbars. The mill in this photograph is famous for having 3 crosstrees, and 6 quarterbars.
Initially the crosstrees would have rested directly on the ground, (or indeed were buried in the ground for extra stability) but since this makes them very succeptible to rotting, the crosstrees were soon being placed on brick piers to raise them off the ground (as can be clearly seen in this photograph).
The body of the mill housed all the milling machinery - a large brake wheel on the same shaft as the sails (the "windshaft") transferred power to a smaller gear at right angles to it, called the wallower. The wallower shared a vertical shaft with the great spur wheel, and from this smaller wheel a "stone nut" was used to drive the millstone. As larger mill bodies were constructed, additional pairs of stones could be driven, by taking further power taps, each using an extra "stone nut" off the great spur wheel. In order to apply some level of control to the mill, the brake wheel could be slowed using a large wooden friction brake around its outer edge.
As already mentioned, the whole body rotated on the central post, in order to face the wind. To allow this to happen, a tailpole or tiller beam extended from the rear of the body. By pushing on this beam (or by using some form of winch or animal power) the miller rotated his mill. The tailpole also provides a useful attachment point for a ladder to provide access to the mill.
An obvious improvement on the early post mill, is to build a roundhouse up around the crosstrees and quarterbar structure. This makes this structure a lot more protected from the weather, and provides additional storage space.
An interesting web site with a few more pics:
www.jrsaville.co.uk/chinnor.htm
A photograph of the mill in 1932:
viewfinder.english-heritage.org.uk/search/detail.aspx?uid...
Tags: Chinnor Oxfordshire Panasonic Lumix GH2 England UK United Kingdom © John Ward Windmill Post Mills
© All Rights Reserved