Denford Software & Machines

Hello!

I have noticed some subtle rings in the surface of a 30mm OD piece of mild steel when facing off. I have been taking a finishing cut of 0.05mm at 10mm/min and about 1000rpm. I originally put this down to the tool I was using as I successfully faced off the same bar a couple times whilst playing with different tools. but have been recently struggling to achieve the same finish when grinding up a side and face cutter.
The rings are quite uniform, about 2mm in width and do appear to repeat at a similar pitch to that of the ballscrew (2.5mm)...

So I`m thinking this may be due to the ballscrew in some way. The screw has two nuts on screwed in either side of the ballnut housing and then locked in place with a grub screw. In my opinion this doesnt seem a good way of doing it (sorry Denford!) and when I add a little preload (by adjusting one nut) the screw operation does feel lumpy. Do you guys think this is the cause of the rings? and has anyone had any experience adjusting these ballnuts?

I have lubricated the screw with slideway oil, would a greese be better?

Thanks

Mike

In the search for info about the starturn 5 at one point I found a manual on here for a mirac this gave a good deal of info about servicing and adjustments. It also gave a list if recom lubes. Might be worth having a look in the mirac section.
Hope that helps a bit

Pete