Definition of "screwing"

I fear there is too much reason to acknowledge the truth of his remarks regarding the original formation of railways, but are the screwings out of the poor pittance received by some of the 20,000 at present employed to keep them in operation, to be the means of compensating the proprietors for the folly and extravagance then displayed?

1843, Railway Times, volume 6, page 1260

But this was a sadly lingering process, since there must be as many screwings and unscrewings as there are copies to be printed.

1854, George Dodd, The Curiosities of Industry and the Applied Sciences, page 35