2. The Type of Bandsaw Machine

Not all bandsaw machines are engineered equal. When evaluating the performance of a bandsaw blade, one must ensure the correct ma-chine is being used for the application. The variety of machines available today has resulted in considerable specialization. Ensure the machine is per-forming the job it was engineered for, Scragg, Edger, Resaw or Log Processing.

performance is the gradual wear on the equipment used to secure the wood during the cut and wear in the tracks of machines where the saw moves through the wood.

Should belts or hold dawns fail to secure the wood properly you will have excess movement which can lead to blade failure.

4. The Bandsaw Wheels

The diameter and condition of the bandsaw wheels will affect saw blade performance. Wheels of relatively small diameter, less than 25", will generally work best with thin bandsaw blades, .035", of the hard edge type. Larger diameter wheels afford the operator the option of using the thin blades, choosing a thicker blade, or opting for the hard back or specialty types.

Bandsaw blade performance will also be affected by the surface condition of the bandsaw wheels. Whether the wheels are steel or rubber covered, the surface should be smooth and free of lumps and bumps. Bandsaw wheels must be kept clean of waste and sawdust build up. Rubber covered wheels must be free of cracks and chips. Steel wheels should be re-ground if excessive wear is evident.

Bandsaw blade performance is also affected by bandsaw wheel alignment. Improper tracking, due to either poor wheel alignment or wheel wear, is likely to result in the set being knocked out of the band, the production of poor quality lumber and unsatisfactory blade life. Check the machine owner's manual to ensure proper wheel alignment and tracking.

Although Saw Guide Condition is #5 on this list, followed by Saw Guide Position at #6, when it comes to factors affecting saw blade performance they are a principle reason for both poor blade performance and poor quality lumber.

Worn or malfunctioning saw guides will result in premature saw blade breakage. Roller guides that have seized will case harden the blade resulting in cracks and breakage. Worn or improperly positioned guide blocks, carbide, steel or composite, will allow the blade to deviate in the cut giving poor quality lumber and broken blades.

Saw guides should be inspected on a regular basis to assure proper clearance, no more than .003" for blocks, and free movement of roller guides. A good start for the inspection program is at least each time a blade is changed or twice per shift.

The first component of saw guide position is relative to the bandsaw blade. The function of the sanguine is to support the blade while cutting. The guide should not maintain constant contact with the saw, as this will generate heat and premature failure. The owner's manual will detail the method of adjusting the guides. Side guides, block or roller, should have no more than .003" clearance. This can be checked with a feeler gauge. Back guides should be 1/32" - 1/64" away from the back of the blade. Problems will arise from constant blade con-tact with the back guide which will lead to back edge mushrooming, back cracks and deviations in the cut.

The second component of Saw Guide position is relative to the work piece. Guides must be positioned to support the bandsaw blade as much as possible during the cut. Therefore, the guide arm must be moved as close to the log or cant as possible. Guides on portable sawmill machines should be repositioned as the log diameter is reduced. Whenever feasible, cants and logs should be sorted so the guide can be moved close to the narrowest cant on resaw applications. A guide arm positioned more than 1" from the edge of the work piece can result in uneven lumber.

The vast variety of species being utilized by the lumber industry today - and processed on narrow kerf bandsaw machines - necessitates a realization that the same bandsaw blade on the same model machine cutting different species or even the same species in a different environment can yield different results. The point here is to consider species when evaluating the performance of a bandsaw blade or bandsaw machine. Refer to the specific gravity chart in the rear of this booklet for relative specific gravity ratings. In the most general of terms, the higher the specific gravity of a species the more difficult it is to cut. Bottom-line, don't expect the same performance when cutting Hickory (.066) as when cutting Poplar.

Also consider that more side clearance is necessary in green softwoods than in hardwoods, frozen wood or dried wood.

the band wheels apart and assure straight cuts. Do not confuse this with Tension of a circle or wide bandsaw which refers to the stretching of steel of these cutting tools.

All cutting tools perform best if properly broken in. It is best to run the saw blade at approximately one half normal feed rate for the first few cuts to hone the cutting edge. Blade will also per-form best if it is always in the cut. Specifically, on single and multiple head resaws, it does the band-saw blade no good to be constantly impacted by the cant. It is much better for the feed speed to be adjusted to match the production speed. Feed the cants butt to butt. An accelerating cant impacting the blade drives the blade into the back guide, risks damaging the tooth and can knock the set off the blade by having the blade ride back on the wheel.

Two other operational practices which will have and adverse impact of the blade life are Idling and Skimming. Both of these two practices should be kept to an absolute minimum.

Idling - Stopping the feed while a cant or log is in the cut. This causes tooth rubbing - as opposed to cutting - and heat build up. Heat build up and tooth rubbing will result in premature blade failure.