Well, let's start with the fact that not all applications for ballscrews involve dusty/dirty environments. Among other places, they're found on the bottom of electrical hospital beds.
Fluids might be an issue...but dust certainly isn't.
Probably only a relatively few ballscrews end up in cutting tools like ours. So, why would they put an unnecessary part on them (thus raising the cost) by default?
I just wish better wipers were easily available.
-- Chuck Knight |