Mill Repairs 2015 - Day 7

– 29th August 2015. Mostert’s Mill Ready for Action again!
Some correspondence from past Chairman Brad Wallace-Bradley led to some concern about a photo I had shown in the previous report of the lower end of the stone spindle, where it runs on the dome washer. This small area supports the full weight of the stone spindle, runner stone, upright shaft and lantern pinion. The photo showed a piece broken away from the periphery which was not recorded the last time the spindle was dismantled for inspection.
‘Bol end’ of the stone spindle showing longitudinal cracking in the wrought iron and chipping

So the first thing we did today was to withdraw the spindle again for closer inspection. The texture of the metal shows longitudinal cracks in the iron which is clearly wrought, and some splaying out at the end. There were two possible courses of action, one to reassemble it like that, the other to trim off a little all around. We chose the second option.
Chamfer ground away on the outer edge
After rubbing away the rough edges with emery paper and cleaning it thoroughly, we refitted the stone spindle and got busy with the business of the day, to turn the runner stone over and balance it. We started by moving the runner closer to the centre of the bedstone, supported on the trolley-jack near the wall and a round rod on the work-table. At all times we had spacers and the many-heights between the stone and the work-table, as well as a plank between the runner and the bedstone.
Runner stone rolled back over the bedstone as far as necessary
When we were close enough to the centre of the bedstone, we started lifting with three of us making sure the runner didn’t swing away left or right, also that it didn’t slip inwards and hit the cock-head of the stone spindle! We had the runner standing on its edge on a plank, then gave it a nudge to balance over and after a moment of apprehension, started lowering it on to blocks and many-heights.
Lowering the runner. We didn’t lower the stone on to the lighter bar fulcrum seen on the bedstone, I was standing on it to reach the chain block!
Now we got to the stage we’d been waiting for! Checking the static balance of the runner! We lifted the runner on a cable through an eye-bolt in the centre of the dummy cock-head I made.
Hanging the runner on the cable on the dummy cock-head
I had brought what I thought were enough weights, a bit more than 7kg. It was immediately clear that this was far from enough!
Alan playing Chess with the weights!
Alan had to go home and bring more lead weights, in the end we had something like 20kg arranged in an arc at the edge.
About 20kg of weights brought the runner into balance
We all agreed this would look ridiculous, so we discussed the options. One was somehow moulding the lead on to a band of hoop-iron around the circumference, which would have been out of sight, but we just couldn’t work out how to actually do that. So we melted all the lead we had laid out into four ingots cast in a tapered Christmas pudding tin we found.
Neville’s blow-lamp wasn’t enough, Alan first went to fetch his, then again his gas hotplate. The three sources of heat were enough to melt the lead.
All that lead consolidated into four weights
We decided to attach them with Epidermix epoxy glue, which we had to go and buy. That was useful because there was another thing to glue, the Provincial Heritage Site tile which takes the place of the old (and to scrap-metal thieves attractive) National Monument badge. Steve had arranged this recently through the very helpful people at the SA Heritage Resource Agency.
The Provincial Heritage Site tile is not attractive to scrap metal thieves like the old bronze National Monument crest was
We mixed plenty of glue and applied it to the wide side of each weight after once again shifting them around to achieve balance.
A generous amount of Epidermix applied to one of the newly cast weights
We could then remove the dummy cock-head and assemble the 16mm rods of the chain-sling, as before using cloths and sacks to protect the upper edges of the runner from damage from the four chains. We vacuumed once again before lowering the runner over the stone spindle until the rods were just not pinched between the runner and the bedstone.
The runner is hanging on the cradle and John is giving it one last vacuum before we lowered the runner into position
We then assembled the tentering levers and raised the stone spindle fully into engagement with the rynd and removed the bars and chains. With the stones lowered together, we could then sling the upright shaft and raise it, swing it over and with three people upstairs guiding and two below, managed to engage the fork over the rynd the same way around as we marked it when we dismantled. We could hold the upright shaft almost vertical as we lowered, avoiding any possibility of damaging the fork or the rynd.
Upright shaft slung, ready to lift and lower on to the rynd
We then assembled the pintle bearing, remembering to add the 5mm spacer between it and the sprattle beam, to correct the out-of-line which we had picked up with the plumb-bob last time. There is still more than enough engagement between the brake wheel cogs and the lantern pinion.
Engagement of the lantern and cogs
There is an added advantage, there is just that 5mm more clearance between the upper band of the lantern pinion and the clasp arms of the brake wheel.
Additional clearance between the upper band on the lantern and the clasp arms of the brake wheel
Meanwhile the others were assembling the furniture.
Furniture assembled
I sneaked one last look at the four weights!
A peek at the weights, we couldn’t test it until the glue had dried
So we are ready to test for the reopening of the Mill on 19th September. We have decided to dismantle the furniture on that occasion and watch the interaction – between the stones, probably lying on the floor in a circle, like some pagan ceremony? 🙂
Article reproduced with kind permission of Andy Selfe
Original can be found here