The wheels were similar in principle to those at Algarkirk but are larger in diameter, being 7'- 4½". high at the outside. They have short wooden axles with cross-tailed gudgeons at each end 2¾" in diameter running in Brass bearings carried in strong wooden frames hanging from the wheel overhead. These pintle bearings run in slides to allow of vertical movement. The wheel is constructed round a 6" cast iron vertical shaft running in a footstep at the base and a common plummer block at the top fixed to a roof beam. At about 8'- 4" above the ground is keyed a cast iron hub, from which radiate 16 hard wood spokes having a section 7"x 4" at the axle end and tapering to 4" x 4" at the rim, which is constructed of 16 cast iron segments having 44 teeth per segment, that is a total of 704 teeth to the complete wheel. High up in the roof and fixed to the axle is keyed another cast iron drum, from which depend 16 diagonal wrought iron tie rods 1" dia. to support the spokes adjacent to the rim. The wheel carries two wooden frames having inclined scrapers to sweep escaping leaves towards the track. There is no movable radial scraper as at Algarkirk to pile up the ground leaves into heaps, so that here they had to be collected and deposited in barrows by hand.
The drive here is from a pinion on a vertical shaft driven by a steam engine of similar pattern to that at Algarkirk. At the latter it is impossible to walk into the interior of the track on account of obstruction from the wheel spokes. This is not the case at Skirbeck where free access is possible to the centre of the grinding track, and in some respects an advantage.
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