Hi Moshe

Moshe I am not aware of any off the shelf MT arbor made to hold a wood
saw blade, there are slitting saw arbors, the slitting saws are mostly
small up to 4" and used in the metal industry, electrical motors,
jewelry, etc.
The slitting saws usually have a notch cut out to help keep them from
slipping, no notch in wood saw blades

If you go to the Busy Bee website you'll find a slitting saw arbor the
cat. # is B044 and you can have a look, Busy Bee also carries a #3 and
#2 MT that is ground and hardened and drilled and tapped for a 3/8"
draw bar, that has a 1"D stub that is soft so it can be machined, the
catalog # B460.

Anyway without some custom machining, I don't know how you would be
able to get a large saw blade on your lathe.

Maybe that is a good thing though, as it is not the safest thing to do
IMO.

Have fun and take care
Leo Van Der Loo