I just got this ball screw from an eBay auction:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=270091651528&ssPageName=STRK:MEWN:IT&ih=017

I'm going to use this for my z-axis. My question is how can I turn the shaft down to install bearings? I see that some guys say that the shaft is too hard to machine. What I was thinking of doing is turning the shaft and using a grinding stone on a dremel and than using a file or fine sandpaper to get a tight fit (I do not have access to a lathe). It seems like there should be a better way to do this, but I haven't been able to find any.

There really is no other way to do this without a lathe and the correct tooling. My advice would be to find a machinist to do this for you.:)

John

OK here's another idea. Can I take a piece of round stock and tap the center with an acme tap and then use this as a collar? It could be secured with Loctite and a set screw? Something similiar to the Acme coupling that is made by DumpsterCNC.

Hey. Centering might be tough if you don't have the facilities to do it right. But it might work well enough to get you up and running. You can also try a stock pipe with the right ID/OD and simply slide it over. Don't forget that it needs to be coupled somehow to the driving motor and those couplers are usually smaller ID than the OD of such sleeve.

When I had to install my machine's screws I used that excuse to buy a cheap chinatown lathe ($600). Then I used that one to build a bench. And that one to buy cabinets.... etc. You know where I'm going. My wife swears all of those things are connected to each other and they wouldn't work without everything else. buah!!!

JR

for the price of the acme tap you could probably have them turned at a small shop

I saw on the Enco site that they have an Acme tap, but does one tap do all of the Acme threads... single, double or four start thread?