RockHound wrote:

On Sun, 1 May 2011 17:16:35 -0700, George W Frost wrote
(in article . com):



One of the many jobs I have had, was in a machine shop making
screws and bolts
the problem with the ones you have may be in the final washing
where the screws are washed in a solution, to get rid of any
residue I can't foresee any problems with an oily residue on the
screws to inhibit their performance


I agree that for the mechanical fastening of the drywall panels to
the framing the oil does not inhibit their performance in any way.
If however you include user friendliness as part of a product's
performance then the oil is a pretty serious flaw. Also in drywall
work it is very important that the mud adhere tightly to the screw
heads so could also be another flaw there. Thanks.

Isnt it to prevent rusting of the tin once pierced by the screw ,
causing the screw to loose grip .

Probably not such an issue in the USA (oh by the way thanks for
wacking bin laden) but in many countries it is , in production its
unlikely they will know the intended market so they all get done.

Plus these are generally shipped by sea so it possibly prevents
corosion build up on the screw itself