Do you want to be able to ensure your workbench is always level even when working on un-even ground? Dose your work area have a slight slope (mine does, due to drainage away from the house) Do you just want new feet for your workmate to go over the old worn ones? 

Meet the adjustable table leg/foot cover, each foot has a threaded insert that can be adjusted to get the table top level. 

After printing the insert should thread into the leg base without any adjustments needed. 

Printed with supports touching build plate, ensuring the threads on the table leg part are facing upwards. I used PETG as i typically use mine outside, but you could use PLA as well.