This specimen, a size 2-1/2, has the ball bearing saw guides that were introduced in 1938. Although one might be tempted to oil those ball bearings, I’m not so sure that’s a good idea. The oil would just become a sawdust magnet that would gum everything up. If you must lube them, I would suggest removing and cleaning them very well before applying a very small amount of graphite-impregnated beeswax.
Photos courtesy of Paul Daigneault.
A Langdon Mitre Box Reference 