The source links on the Parts List page go out of date from time to time.
Many of the parts can be fudged from whatever's on hand, (like (C-13) can be made from a piece of 1/4 inch brass water pipe drilled out to 3/8, or by wrapping brass welding rod around the axle like a coil spring). But decent ball bearings for the blade shaft are critical even if they don't match my specs exactly. If you live someplace really rural, ask around car & truck repair shops, or farm equipment suppliers. Bearing have retained their Fafnir numbers in use since the '60s, and are also used by Timkin Bearing, Torrington, & BCA to name a few. To find a supplier near you, just google the number, (for example:
GRA014 RRB, not
B-4). Prices go from $4 to $30 (2011). Same for electrical parts.
Stainless foil is no longer carried by Napa Auto, though it may be carried by one of the other auto parts stores like Kragens or O'Rileys, there's like 10 or more chains. JC whitney carried it for awhile but even they stopped.
Before stainless was invented, copper was used, and it still works fine if you can find it. Aluminum foil tape will work for a few years but will corrode and need replacement later. An acceptable hack for stainless foil is tar paper backed copper foil used by builders to seal around windows. The foil is thin as paper, comes 6 or 8 inches wide, and can be bought by the foot so you don't have to buy a roll. Peel off the tarpaper, cut it in 2 inch wide strips w/ scissors, clean off any tar with gasoline or mineral spirits. Apply it with formica adhesive and tacks or staples like the plans say. Some kind of plastic tape might work (with stapes) but (and because) there are a million kinds of plastic. Some are probably feasible but plastic is destroyed by sun light so I won't recommend any without testing them first.
If you know of another source for 2 inch wide x 10 feet long roll of heavy stainless adhesive foil tape, please tell me where and I'll include the info here.