Atlas 12 in half nut "Brass ?"

R

Redneck79

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I put new half nuts in my 12x36 and used it a couple months and the teeth are gone in it. Is this common with zamak?? I see brass replacements on ebay, any experience with these?

Really sucks i had the whole weekend to work on lathe projects and now im done till i get it repaired.
 
zamak is a mixture of zinc, aluminum, magnesium, and copper.
zinc is the base metal, aluminum, magnesium and copper are added in small concentrations to create the alloy.
is is not an especially strong nor is it wear resistant
it is a cheap metal that casts well, without the need for much machining after casting.

brass will wear a lot better, bronze would be even better than brass-
but i'm concerned that you may have an unknown issue that may be eating up the half nuts,
being that you replaced the zamak nuts not long ago

further investigation should take place before you buy another set of nuts

another consideration may be to make a set from delrin
it has a lower drag coefficient and is surprisingly tough being a plastic
 
Bronze is a go to for that, but as Ulma doc said you may have other issues to look at ......................
 
What would cause that?? The miter gears arent in it, that leaves no resistance i can see.
 
I would agree that something else may be wrong. My 3996 has the same part number parts in it as yours does. It was bought new in 1981 and is still not worn enough to consider replacing. I would suggest calling Clausing and asking for Tech Support. But remove the new nuts first so that you can look at the wear pattern.
 
went out to check the rest of the lathe over and with the apron off the carriage was harder to move than i think i tshould be. I may have overtightened the set screw on the back. would that be enough resistance to do it?
 
Removing the apron shouldn't have any effect upon the force required to move the carriage

I assume that you mean the four Carriage Gib adjusting screws. With them properly tightened, the increased force required to move the carriage should just be noticable. But even if they were significantly over-tightened, wearing the half nuts out in two months shouldn't happen. Maybe two years or twenty years. I assume that you are oiling the threads on the lead screw and thrust bearings daily or before each day of usage.
 
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Always oiling. I am OCD when it comes to lubrication be it the lathe or me diesel 3/4 ton. I dont know what else it would be. the lead screw is in excellent shape, all other apron parts "except mitre gears are absent" are in great shape, It hasn't crashed and i watch my feed rates close.
 
OK. Check the wear pattern on the half nuts and confirm that they close fully. And call Clausing next week. Talk to someone in Tech Support, not the parts people.
 
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