Using stainless steel tube for linear bearings

[shoeswith]

I thought stainless tube was usually sanded or sanded and polished, not ground.

OTOH just because I think something doesn't make it true

Yes you are probably right its probably sanded and polished. I've measured it with a micrometer and it seems pretty accurate. I can't see why in this case it couldn't be substituted for round linear shaft. I have it from a previous project so its going to cost me nothing. Is 1.6mm too thin a wall thickness? It's harder than mild steel ive drilled it but I've never drilled standard linear shaft. People say its hardened but actually how hard is it?