I don't know, John.
I can produce no authority for this, but I imagine that bronze might be the best material for feedscrew nuts. Mine was originally cast iron, but as a result of certain "unintended consequences" of remachining my saddle dovetail I replaced it with one of the brass ones you kindly made and included when returning the tap, and that works just fine.
But if bronze is good for feedscrews, why not bronze half nuts on leadscrews?
Returning to G's original query, it has been suggested that he uses the adjustment which reduces backlash by rocking the feedscrew nut slightly. If his cross slide was stiff throughout its travel, that might help, but it only stiffens up at the outward end. That makes me think the cause probably lies elsewhere; hence the suggestions I put forward earlier.
Andy
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--- In 7x12minilathe@..., John Lindo wrote:
Andy Franks in reply to this recent post.
Do different mini lathe (Chinese manufacturers)??opt for brass and or cast iron cross feed nuts.?
Does cast iron have physical self lubricating properties (graphite) and would phosphor bronze have even been a better choice of material ?
My ??Real Bull lathe was??originally??fitted with a cast iron nut.
As you remember opted with the cross feed mods I did to put in double nuts (only to stop the screw
running off the nut when I did the extended the travel change) and made 2 new nuts in brass so
one of the nuts is always in contact with the screw at the end of travel towards the splash guard.
Naturally re positioned them on the cross slide,backlash and or slop now is not an issue.
I think double nuts helps in some of the gib issues we all seem to have,being that the screw is better supported.
Again,many thanks for the loan off your LH Tap you made, it worked very well.
Still have to make my own tap ,it's a round to it job.
But thinking now I should of used cast iron , although brass the has never been a problem.
Best to leave alone at this moment.
Regards
John L
