OK now I'm confused. I thought most small wood lathe chucks has the body threaded 1"x8tpi and would accept various spindle adapters with that OD thread.
Then I get a reply from Grizzly that such adapters won't fit their chucks and they don't have anything to fit my Shop Smith with 5/8 plain spindle.
I was looking to buy their T10810 kit that fits 1"x8tpi spindles.
In the picture it "looks like" a normal thread-in adapter.