Well I can see how it works.............sort of, but how to adjust it? The wedge appears to force or at least hold the two threaded bronze pieces apart, but there appears to be nothing to hold the wedge down. I see the shoulders that bear on the split pins to stop the wedge dropping out. But unless the sides of the wedge have serrations like step block clamps for milling, I don't know how you would go about adjusting it. I am msytified. I would take it to pieces, but then I do that with everything, and somtimes even get some of it back together AND working! I have checked both my Colchester Mk1/ 1.5 books and the 1800 and there is no nut of this type shown in the spares section, the 1800 one is sort of similar, but uses a split nut with a top wedge and adjusting scres. You could take one of the split pins out and see if there is a thread in the hole, Anyone else got any ideas?
Phil