When is it time to have a bit resharpened?

If you see a decrease in surface finish quality decreases, you see a need to increase the horsepower in order to cut, or there’s an increase in noise level, it may mean that your bit is dull.

Heat is the major reason tools become dull. To reduce the amount of heat, increase the chipload or reduce the RPM. The number of cutting edges on a router bit determines how the chipload is divided. The formula for determining chipload is: chipload= feedrate/(rpm x #cutting edges).

With regards to feed and speed, start at the low end and slowly increase feed rate until: 1) the edge finish deteriorates because of tool chatter; 2) the machine defaults to a slower speed due to tight radii; or 3) the part moves or is pushed off the vacuum.

Source: LMT Onsrud. For information, visit Onsrud.com or call 800-234-1560.