We use screws which have combined hex/posidriv heads with
serrations under the head, which eliminates the need for star washers.
We find these work very well for zinc plated parts. On epoxy painted
parts, they also seem to cut thru the paint and give a satisfactory
result - you might feel "happier" if you have more than one screw
for any given part.
We also use self-clinching PEM nuts with good results.
Typically we find that where a grounding conductor has been
brought to a particular area of our products, we would still
pass the 0.1 ohm, 25A test when we remove the conductor.
Conductive paint has been mentioned - we have used this in
the past, but our suppliers now don't want to use it because of
concerns regarding toxicity. In any case, the aforesaid screws
would cut right through the coating.
Regards,
John Crabb, Development Excellence (Product Safety) ,
NCR Financial Solutions Group Ltd., Discovery Centre, 3 Fulton Road,
Dundee, Scotland, DD2 4SW
E-Mail :john.cr...@scotland.ncr.com
Tel: +44 (0)1382-592289 (direct ). Fax +44 (0)1382-622243. VoicePlus
6-341-2289.
