I am making the male spindle tapers that slide into the female socket.
-Slide? Odd.
The female socket is threaded on the bottom and there rods that go through the male spindle taper and thread into the female, This is called a postiv-lok spindle design by the manufacturer. Tightening the threaded rod pulls the male taper in and loosening ejects the spindle.
-Based upon your brief description it doesn't sound like there's much of a problem with dis-similar metals provided they're not left in assembly for long and/or the presence of moisture. The acids in some species of wood can also promote etching/corrosion but I'm sure you're aware of this. A simple disassembly and cleaning should be sufficient to prevent this.
Hopefully my explanation above conveys the message that this is not a high tolerance spindle fit - on the few I measured the run out on the spindle was in the neighborhood of 010".
-Runout of .010" certainly isn't precision and if the taper isn't precisely matching, it won't lock as a regular taper would. But that doesn't really matter if the assembly is held together by a threaded fastening. I might suggest that the runout may be due to a mismatched taper having a narrow ring of contact with each other, this is just speculation but does seem as though it would greatly affect the finish with it "bouncing". A proper taper is supposed to locate as well as lock.
The male taper sockets I made were from a non-magnetic stainless steel.
-Fairly soft material in the 300 series. Not a bad choice but it does have a tendency to gall on itself so using a SS threaded fastener/nut with it can be somewhat problematic if both SS components are in contact with each other. I'd advise using a very thin film of something like anti-seize, any type of grease, or even milk of magnesia (don't laugh we used it in the Air Force) to prevent galling and/or micro-welding. This and the regular disassembly/cleaning should be enough. If corrosion develops a very light application of 600 grit cloth is in order.
A few links to the machine rebuild and the spindle construction. The first page of the rebuild link has some good pictures of the as received machioe and spindles. Hopefully this answers questions.
-Didn't find much in photos about the tapered spindles until Page 4. Had thought some photos closer than 6 feet away would better depict your application, I guess not. What I did see showed some fairly rusted spindles that will likely clean up nicely but was a bit surprised at the proportions of taper-to-drum. Seems like a small/short taper in relation to the working length of sanding drum, perhaps I'm just using metal working machinery design as my yardstick. Still, it seems as though that makes it even more important for the tapers to have a proper contact area by matching the tapers as best as possible. Runout from mismatch over that length I would expect to have vibration that increases the further out you go. A taper in a female socket can still be calculated with two different sized ball bearings, a depth mic, and a simple trig calculation. It's entirely up to you whether the male tapers you make are good enough or not. Hope this was of some help. I'm about 300 miles West of you, have a machine shop and CAD software if I can be of further assistance.
