Small spindle head

[Robin Hewitt]

And as for pre-loading the bearing - it is internal in the double row bearing so I don't need to (and couldn't) do anything about it. Ijust need to secure the bearing in place.

Not pre-loading, just loading. As drawn it resists a push but not a pull.

If the double race is tight in the housing you could put a sleeve down inside so when you nutted the pulley on the top you pinched the double angular inner ring.

That'd do it.

Edit: I do have experience, here is a double angular bearing loctited on a spindle from my junk box