My only exposure to the use of long center pins was a class at NYSCON 2003 taught by Ken Walkup called: "Rebushing Action Parts Using the Renner System". The long pins, which he called "Shrink Pins", come in mm sizes 1.25, 1.275, 1.3, 1.325, and 1.35, 60 cm long. I ordered some from Renner USA, item number GEN-0610, which were about $2.50 each in Oct '04. Ken suggests buying at least 3 of one size to fit 88 parts. The idea was that an entire rail of parts could be rebushed efficiently by using the Renner pre-glued cloth (Renner part 1049, get six strips per rail), pulling the cloth thru the bushing, pulling on the next part and leaving 1/16th inch between parts until the cloth is full. Cut the cloth flush with the left side of each part to separate them, and slide them on the shrink pins. Start the pins by hand, then use pliers to pull the pin. The first 3 inches of the pin must be tapered and roughened (by you) to ream the bushing to size. Polish the pins before you start sliding on bushings, so your first parts don't end up full of tarnish gunk. Fill up the pins with parts. It takes three pins to do an entire rail of parts. Soak the pre-glued cloth with an equal mix of alcohol and water to activate the glue and size the wool. Leave them overnight to dry. They will be very loose on the pin when done. Slide them off, trim the excess bushing cloth, and re-pin as normal with regular pins. Ken says to use a shrink pin one size smaller than your new center pin, or about the same size as the original pins you took out, since you often choose a new pin about .001" or .025mm larger than what was in the birdseye originally. This was a good class, and included many more tips on production-efficiency pinning, when to do it or when to buy new parts instead, etc. The point of the long pins was simply to keep speed up, individual pin handling/reaming/burnishing down. He certainly didn't recommend using the long pins to assemble the finished parts. Sliding a birdseye down a two foot pin doesn't sound like a good idea to me, but that's my LEHO (limited experience humble opinion). Greg Graham __________________________________ Do you Yahoo!? Yahoo! Mail - 250MB free storage. Do more. Manage less. http://info.mail.yahoo.com/mail_250
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