Thanks all for the responses. Quick too! I ordered up a piece of 1144
(stress proof) 1.25" diameter. 1" would have been nicer, but I assume
tolerance= -0.006 means the piece is smaller than what I need. I
checked out all the other steels recommended and "fair machinability"
scares me. This shaft has three diameters, and is threaded in two
spots. Did I mention that i am a wood guy? I really like this saw
however, and will give it my best shot to get it running again.

I took the old shaft to the grinder, and the sparks were more
"fireworky" than a piece of steel pipe. I assume this means it is an
alloy steel of some type. A file cuts into it easily, so it is not
hardened.

Luckilly there was not a lot of drama when the shaft broke. The blade
fell off the machine while cutting, and when I tried to re-mount it,
the upper wheel broke free.

I will take some photos and post my replacement shaft.

Thanks and happy new year!

Andy