Problem- Plastic nut chatter with acme lead screw

[hootie]

Has anyone experienced chatter issues using delrin nuts on acme lead screws? The acme thread is 1/2-10.
Thanks for your help,
Hootie

[Phife]

I do, mine chatter like crazy unless I use generous lubrication and run a warm up program to make sure the leadscrews are evenly lubricated before starting machining every day.

I use While Lithium Grease on my Nuts/Screws.

If you use an oil you will find the spinning screw tends to fling oil everywhere, grease will stay on the screw better.

[ger21]

I use oil and have not had a single drop flung anywhere. My screws are spinning at 700 rpm. I only need about 3-4 drops along the 5 ft screw, about once a month. After running the machine back and forth a few times, I wipe off any excess oil.

But I've never had the nuts chatter, either.

[CarveOne]

Dry film spray lube works well for me. Du Pont Multi-Use or garage door spray lube don't fling oil and leaves something like soft wax on the threads. Dumpster nuts will eventually show little curls of it between the little slots.

CarveOne

[Phife]

I know that I need alot more than a few drops of oil to keep my nuts from chattering. It seems like my nuts are really tight, so a couple of drops is not enough to cover the entire screw, I found there were "dry" spots where the nut would still chatter.

And with my machines design the leadscrews are above the bed, so the flinging oil was a real issue since it got all over the work when the machine did a rapid.

What I found was that the oil tended to end up in one spot on the screw beacuse the program I am running only went that far down the screw. Then when the machine rapids to another spot all that built up oil got flung everywhere. My screws max RPM are around 1000.

Ive tried 3in1 oil, WD-40, Jigaloo and Fianally White Grease. WD-40 and jigaloo seemed to dry up quickly, I had a 4 hour run on my machine and the screws got dry about half way through and the nut and screws got really hot, when I sprayed more lube on it instantly vaporized!

So now that im on the White grease I havent had any problems, it lasts long and doesnt fling.

Good luck with your Nuts!

[MattTheNoob]

A company named Nook makes plastic acme nuts that I have used with great success on non-cnc applications. No lube. Virtually no backlash (I know that means very different things to different people) and no chatter... however, now that I think of it, the speeds were closer to 100-200 rpm, not 700 rpm.