model b oil

Any light weight oil. A drop or two where the shafts go through the berings every batch start. If the motor has oil ports oil about once or twice a year. Where we live we have a lot of blowing sand/dust and my tumblers stand idle most of the ime. If I'm home long enough to use thm I'll oil them at startup. My last motorhome had a V-10 engine that required 15-20 wt. oil. I'm using that oil until it's gone. When I was working we used a muliuse oil called "Zoom Spout" that had a long applicator nozzle. You can find that at Home Depot/Lowes in the cooler section. 3-in-One oil, light weight automotive oil (10-15 wt) would also work.

I've been using WD40 -- that bad?

Hokay. I'll use veggie instead then.