Inboard drums - No spindle nut locking tabs. Is this normal?

I don’t think that’s normal, you should have the floating plate that locks into the big inside nut and then has dowel pins that screw in or you should have the tabs that fold over having nothing sounds very scary. You can go to a trailer place and buy either one and install them that’s what I would do!

 

I have seen hundreds like that, If they are torqued properly it is not a problem.
Believe that locks came on the scene for liability issues.
If you are going and buying stuff maybe look into the Stemco single nut with snap in lock ring.
There are a lot of old trailers running around here with the set up you ask about. Mostly 80's models and the Butler with the 721 anti-lock brakes. It was made in 1975 and the wheels still have not fallen off.
What are 721 brakes? We called them 7 to 1 they will fail. Same as the early 80,s 721 tires.

 

There were a few Rockwell steer axles like that where you just torqued two nuts together against a big washer plate. The rockwell rear drive in my ‘51 Diamond T is like that too. Inner nut sets preload and outer nut jambs into the inner nut to lock it into place.

 

Yes but I get spooked on the steers. Buy a bend over lock to put on them of it does not have one. They are inexpensive and are available for drives and trailers also.
Liability I guess? Probably an old company policy along the way and I just keep doing the same thing.

 

Just make sure you put it all together right if you don’t buy locking tabs like mentioned above. This trailer came into the shop today like this...