Mahogany cover, with two lubrication feed pots and separate winding handle, for double grindwheel model
Mahogany cover for model of double grindstones, scale 1:4, by William Muir & Co., Manchester, 1853, with two lubrication feed pots and separate winding handle.
Muir patented his double grindstone in 1853. The Dictionary of National Biography records: 'A model of his grindstone, patented in 1853 (No. 621), may be seen at South Kensington Museum. This consists of two stones running in contact, one being caused to traverse longitudinally, with a very slow motion. In this manner each stone corrects the defects of the other, and both are maintained accurately cylindrical in form.'