It's ben about 30 years since I did one, but If I remember right there tapered bearing.
On the ends there's threaded end caps that preload the bearings that need to come off to get the shaft out.
I think there was 2, set screws in the faces of the caps to lock it in place. Back the screws out and remove the cap with a face pin spanner.
I think one was left and one was right hand thread.
May want to go on the Ridgid website and see if you can find a parts breakdown.
If you live near a city I'd be removing the bearings and looking for the stamped or etch letters and numbers on both the inner and outer races and buy them there instead of from Ridgid.
I most cases there's 3, letters first. That will tell you who made the bearing.
NGK, INA, FAG, NHB are common letters.
The inner and outer races will have differant numbers.
Thanks for the quick response. This one I am working on has the babbit type sleeves on the rear and maybe bronze or something on the front.
The front has a ball type thrust bearing for end play.
I just cant figure it out. Maybe the front hub does twist off. I haven't tried that. There aren't any visible retainer rings or set screws.
After checking with Ridgid, there manuals don't show anything this old. Some information showed the 400 series started in 1940. This is a slightly newer model with a hand chuck, or has been updated from the wrench chuck.