Nick didn't specify screw diameter, but assuming #10-32: Try #96024A310 from McMaster-Carr (www.mcmaster.com) These cut threads into aluminum pretty well.
I also use stainless "external star" washers for the ground lug task: #98438A230, same source. One washer between lug and solar module frame bites into both surfaces. The above mentioned screws require a 5/32" pilot hole. If your modules don't already have that you'll need to protect the Tedlar back sheet with a scrap of wood then drill through the aluminum flange. This operation is possibly non-code, possibly non-acceptable to your authority having jurisdiction, and possibly a reason for the module manufacturer to disallow warranty on the drilled modules. Drama, drama, drama. A 5/16" hex bit is required to drive the thread cutter screws and I find this cannot be done by hand. A cordless drill works but be careful to not strip out the aluminum threads you're cutting. Get them tight...but not too tight. Side Note: The same screws do not tap well into the thin NEMA 1/NEMA 3R steel pulling boxes. The cutting teeth seem to grind away before they get a good bite in the steel. Jolliness, Mick Abraham, Proprietor www.abrahamsolar.com Voice: 970-731-4675 On Fri, Oct 23, 2009 at 6:17 PM, Nick Soleil <nicksoleilso...@yahoo.com>wrote: > Hi wrenches: > I am looking for a new source for stainless steel, self-tapping, 32 > thread per inch screws to bond Ilsco lugs to module frames. I used to buy > these from Fastenal, but they don't supply them anymore. I have been using > WEEB lugs, but one city jurisdiction doesn't allow them without the letter > of authorization from BP Solar. I have contacted BP a couple times, > requesting that they provide a letter to WEEB, and I heard, "it's > complicated." I guess so. > Maybe I will bolt the Ilsco lug through a threaded hole. > Nick Soleil > Project Manager > Advanced Alternative Energy Solutions, LLC > PO Box 657 > Petaluma, CA 94953 > Cell: 707-321-2937 > Office: 707-789-9537 > Fax: 707-769-9037 > > > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: RE-wrenches@lists.re-wrenches.org > > Options & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org > > >
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