To arrive at the tooth load for a saw, you must first know how fast the board is feeding into the saw in feet per minute, the revolutions per minute of the saw, and the number of teeth in the saw.

Using the above information, the formula to find the tooth load is:

FEED IN FEET PER MINUTE TIMES 12 DIVIDED BY THE REVOLUTIONS PER MINUTE TIMES THE NUMBER OF TEETH

EXAMPLE:

50 F.P.M. x 12 = 600 / 3600 R.P.M. x 80 teeth = 288000.

600 / 288000 = .002 tooth Load

You will note that it is necessary to know the feed rate to arrive at the tooth load. This of course means that you cannot figure the tooth load on saws fed by hand. 

The tooth load you figure for a saw is only true if the saw is true. If the bore of the saw is bad the saw will not run round. If the shaft is small the saw will not run round. And of course the teeth must all dial indicate the same height and width for the tooth load to be uniform. 

If a saw has alternate top bevel teeth, you will have to double your tooth load figure. Triple chip style saws also cut on every other tooth. In the case of combination saws, the tooth load will also vary depending on the individual saw geometry. 

• Generally speaking, saws cross-cutting wood should not exceed .005 tooth load.
• Saws ripping wood should not exceed .020 tooth load.
• Saws cutting aluminum and other non-ferrous metal should not exceed .002 tooth load.
• When finer finish cuts are required, use less chip load.
• Tooth load gives you a good place to begin when recommending a saw or trying to solve a sawing problem.

Previous Page  /  Next Page