Monday, 27 May 2019

Hunting for the cause of the hunting

We had been noticing that when water, and therefore power, is short the mill speed varies, slowing down once per revolution of the waterwheel.

Eventually, careful observation showed that the problem was that the angled gear teeth on the pit wheel, which shares its axle with the waterwheel (visible at the left of the upper picture and just seen over Neil's right shoulder in the lower) were not engaging at a constant height with the matching angled teeth on the wallower (showing just over the beam in the upper picture and half visible at centre right of the lower picture).

With the wallower higher, the coupling is slack.  When the wallower meets the pinwheel lower, there is considerable pressure exerted due to the angled gear faces.  The top of the wallower appears to move from 1cm below the top of the pinwheel to 2cm above.

Clearly something has run a bit out of alignment.  We made an attempt to help matters by twisting the pinwheel slightly on its axle and repacking the wedges.

This weekend there has still been some hunting, but we've had a bit more water so it has been less of a problem, so not sure if we have really improved it.

Work on the third pair of stones

The third runner stone lifted
 While we are waiting for the go-ahead to restore the second waterwheel, we decided to overhaul the moving parts of the drive for the third pair of stones (out of 4).

This involved the usual process of lifting and supporting the runner and removing the bearing (strips of wood) from the cast iron fitment in the bedstone.

This time we go on from there and remove the drive shaft, take the bottom bearing out and take out the wooden tentering beam.  This is mounted in a cast iron box set into the wall, and that was in a scruffy condition, so that had to come out too.  Here is Dave Freak cleaning it up with a wire brush prior to giving it a coating of Waxoyl.

The box was then fixed back in the wall with lime mortar, and the beam re-inserted and hung from the tentering bar.  The final picture shows Richard and Peter fixing the box.