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Saw Blade Stripping and Breakage

Stripped bandsaw blade teeth is a common problem, and there are several causes to consider.

A big factor includes use of the incorrect tooth pitch. Too small teeth for the size of the material fills gullets halfway through the cut. Pressure builds on a single tooth until it breaks and becomes lodged in the cut. Now the other teeth come in contact with the broken tooth, resulting in more broken teeth.

Follow the m.o.m. rule: Minimum, Optimum, Maximum, which requires a minimum of 3- and a maximum of 24 teeth engaged in a cut in order to achieve the best TPI and a smooth cut.

3 —  minimum of three teeth on the work piece at any given time.

6 – 12   — optimum number of teeth on the work piece.

24 —  maximum of 24 teeth on the work piece at any time.

The teeth will straddle the work piece with too few in the cut, leading to stripped teeth — better to use a coarser pitch.

Gullet overload will result from having too many teeth in the cut, causing blade bounce and stripped teeth — not enough gullet capacity to hold all the chips.

Other causes for tooth stripping and breakage include the following:

Excessive feed rate — too many pieces being cut simultaneously cause over- under- penetration. Adjust the feed rate.

Too slow band speed — when cutting moderately soft materials, a too slow blade means the teeth aren’t moving through the material quick enough, creating a too thick chip. Gullet overload results in stripped teeth. Review the feed and speed chart.

Improper break-in — to achieve full saw blade life, break-in is important. Follow the proper break-in procedure.

Misalignment at weld — crooked welds will lead to blade breakage.

Low or bad tension — blade slipping due to low band tension. Re-tension is required.

Work piece moves — blades bounce or jump when passing through the saw’s guides, causing issues in gullet overload or  expensive damage to the head feed system.

Chip welding — the chips are carried back into the cut, causing stripped teeth. Replace the chip brush.

Coolant problems — check the concentration, adjust the fluid flow, and add coolant nozzles if needed.

Material too hard — review feed and speed chart and adjust cutting parameter(s) as needed.

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