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I'm passing on an enquiry I've received from George Croome of the River Antoine estate in Grenada concerning the properties of steel made in Sheffield in the 1840s. I'm not competent to comment, but perhaps someone on the list may be able to assist. If so, please contact Mr Croome directly at [log in to unmask] "In Grenada, my company operates a small rum distillery, using sugar cane juice grown on the estate, which is crushed in a 3-roll mill made by George Fletcher & Co. of Derby in the 1840's. The mill is still driven by the original water wheel - the only working water wheel in the Caribbean.... The mill has eight horizontal through-bolts which take the thrust from the two bottom rolls and are adjusted as the rolls & bearings wear.... After 170 years of daily operation, the bolts have started to elongate and break. Fletchers (who are still in existence as Fives Fetcher) are very good, but they tell me that the warranty has expired ! I need to replicate the bolts, using modern steel, and I have been trying to 'reverse-engineer'. For that, I need an estimation of the original load-carrying capacity of the bolts. I have engineering data books showing steel properties, going back as far as 1890, but I know that there were huge improvements in steel-making in the 50 years before that time, so the 1890 figures might not be representative . Fives Fletcher are looking back in their archives to try to calculate the theoretical total tensile load on the eight bolts as a component of the thrust from the rolls. I am hoping that we could use a continuous threadbar rolled from 50,000 psi yield steel perhaps 1.2 inch OD to replace each bolt, as such threadbar is readily available. My question therefore is, can you give me your opinion (i.e. hazard a guess !) at what type of steel would have been used to make these bolts in 1840, and what allowable stresses might have been assumed by the original engineer."