most old table saws are designed to run approximately 3500 to 4500 rpm sleeve bearings or babbit bearings require slower speed to prevent galling the shaft and bearings. the critical limit on saw speed is the design limit of the particular blade being used. all modern blades state the maximum RPM that the blade can be run at on the blade itself. most carbide table saw blades have a max RPM of 5500. it may be necessary to replace the bearings on that old saw.

JMHO

Carl