I installed these on a small Emerson 4.4 cu.ft. refrigerator in my shop. The refrigerator is located inside a vented cabinet to protect it from grinding dust, etc.  I occasionally pull it from the cabinet to clean behind it.  These casters have made this task much easier.  The wheels installed without a problem at the rear of the refrigerator by drilling two holes and using an additional nut.  Replacing the adjustable feet in the front of the refrigerator was a little more difficult.  I had to drill and tap the existing threads for one of the front casters.  For the other front caster, I tack welded a 5/16" nut to the refrigerator.  Works awesome.