I removed these screws from a lot of Herman Miller stacking fiberglass shell chairs that I purchased at a university surplus auction 20 years ago. 
Eames Herman Miller SET OF 4 angled rubber boot glides LCM DCM DSS DAX
Herman Miller Eames Glides For H-Base, Shell Chair Stacking Base. (Set of 4)
Set Of 4 Vintage Original Eames Herman Miller Fiberglass Chair Screws
RUSTIC OLD VINTAGE FRENCH SET OF SHELVES BOOKCASE - SET OF 3 PEAR CRATES BOXES
Modern Dining Table Set and 4 white Faux Leather chairs kitchen table set of 4
Kosy Koala Dining Table Set With Set of 6 Chairs Dining Room Furniture
