"Pete C." fired this volley in news:5196c2fd$0$40157
:

It's not an Acme screw or other lead screw, it's an auger kind of feed
screw. Take a look at http://www.piteba.com for a s

Don't even have to look. If you'd said feed auger, I'd have been very
familiar with them. They're an integral part of many chemical feeders.

Have fun.
Lloyd