John Gruber Clayton (Jill) Post Mill Model
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| Model Type | Post Mill |
| Model | Jill Windmill |
| Model Maker | John Gruber |
| Height | 48cm |
| Width | 41cm |
| Depth | 23cm |
| Power | 1xAA battery |
| Switch | Weight Wheel |
John Gruber's model of Jill Windmill at Clayton is his second example of a post mill. The switch for the sails motor is the Weight Wheel on the back. In the original mill, according to Simon Potter, "There is a chain bolted to a groove in the wheel's rim. When the chain is moved it turns the Weight Wheel, which operates a gear train connected to a shaft, on the other end of which is the Spider mechanism at the centre of the Sweeps. The rotation of the Weight Wheel moves the Spider out or in, which respectively opens and closes the Shutters on the Sweeps. This the principal of Patent Sweeps. In theory a weight on the chain would react to wind pressure so as to open and close the Shutters automatically and thus maintain constant Sweep rotation speed." The shutters in John Gruber's model are fixed and there is no connection between the Weight Wheel and the shutters.
In the model, the axle of the Weight Wheel is attached to a smooth brass wheel with a screw in the side. As this rotates, the screw pushes a leaf switch closed, thereby engaging the motor.
Access to the battery is possibly through the door of the mill model. However, for greater access to the battery holder, switch assembly and motor, the rear panel of the mill body may be removed, see below.
Removing the Rear Panel
- Remove the split pin securing the tail pole assembly.
- Remove the tail pole assembly.
- Undo the nuts and bolts of the two steps hinge brackets.
- Remove the steps.
- Gently pull out the rear panel.
Maintenance Records
| Date | Status | Action | Maintainer |
|---|---|---|---|
| 03/06/2022 | Motor not turning when switch engaged.
Battery holder and wiring appear to be OK. |
Back panel removed.
Battery replaced. Issue NOT resolved |
Jeff Best |
| 03/06/2022 | Dirt and spotting on model surfaces. | Tail-pole and part of roof cleaned.
Further work required. |
Jeff Best |
