Run the same test as above. With hydraulic tension you need to de-tension 20-25 lbs. at a time. After you have removed the flutter, add an extra 50 lbs. of pressure. Remember the pressure on your gauge.
ALWAYS DE-TENSION YOUR BAND SAW BLADES. The next time you use the band, tension it to the same setting you found after running the flutter test.
Run the same test as above. With air bag tension, you need to de-tension 15 lbs. at a time. After you have removed the flutter, add an extra 15 lbs. of pressure. With the air bag tension you usually have a gauge and you will know exactly where low tension is by reading the gauge. ALWAYS DE-TENSION YOUR BAND SAW BLADES. The next time you use the band, tension it to the same setting you found after running the flutter test.
NEVER USE WATER as a lubricant on band saw blades. Water is NOT a lubricant and is the WRONG thing to use for many reasons.
For proper lubrication mix HIGH ADHESION CHAIN SAW BAR OIL, with 50% kerosene or diesel fuel. Apply the solution with a spray bottle to BOTH sides of the band about once every four minutes, while the machine is running. When this lubrication is applied, the sound of cutting decreases over 50%. DO NOT APPLY AGAIN until the sound of cutting starts increasing. I guarantee you will be amazed! Longer life; No pitch buildup; No rusted or pitted bands! A great delivery system is the 12 volt windshield washer assembly out of an old car!
In both cases, we know for a fact that lubrication of the body of the band increases band life by over 30%. Applied sparingly, you can cut grade lumber with NO staining to your product and we feel it also enhances tire life.
When you are done cutting for the day, take the tension off your blade. Band saw blades, when warmed up from cutting, always stretch; and upon cooling shrink by tens of thousandths of an inch each cooling period. Therefore, blades, when left on the saw over tension themselves and leave the memory of the two wheels in the steel of the band, which will cause cracking in the gullet. When you leave the band on your saw under tension, not only do you distort the crown and flatten out the tires (which makes them very hard), but you also place undue stress on your bearings and shafts. Believe it or not; you can, and will damage your wheel geometry sooner or later and considerably shorten bearing life. You are also crushing your tires or V-belts.
Appropriate set is when you have a mixture of 65%-70% saw dust and 30%-35% air in the space between the body of the band and the wood you are cutting. The SIGN you are looking for, when you are running appropriate set, IS A GOOD 80%-85% SAW DUST EJECTION FROM THE CUT! If you are running too much set for the mass or thickness of the wood, you have too much air and not enough saw dust. You will leave EXCESSIVE loose saw dust and most likely it will be accompanied by tooth marks. If you are running under set, you will have no air flow pulling the saw dust out...The SIGN for this is excessive HOT packed down saw dust. This is the most damaging thing you can do to a band. You will have short cutting times and premature band breakage. The saw dust should be warm to the touch, not hot or cold. One last thing, a band that is excessively under set will cut in a wavy motion, and a band that has an improper HOOK ANGLE and is UNDER SET will cut a bow across the board every time! (See TROUBLESHOOTING)
If you are cutting very hard wood, the blade will probably rise in the cut. This is called push-off. The hook angle must be brought back to 8 degrees. You will notice as the angle goes from 10 degrees to 8 degrees, the tooth becomes more perpendicular, thus INCREASING its penetration factor.
As the tip of the tooth goes from 10 degrees to 12 degrees the tip of the tooth starts pointing forward DECREASING penetration in hardwood. If you use 8 degrees on soft wood the blade may chatter because it's over feeding itself, unless it's very knotty. You need to use an 8 degree hook angle for hard knots. On the other hand, if you use a 12 degree hook angle on very hard wood, the tooth skips over the hard surface because the tip of the tooth is pointing too far forward.
Having a 12 degree hook angle in hardwood cutting causes push-off making the band ride up. The band locks itself in place, cuts straight across, and drops down at the end of the cut. This also burns up the band and over tensions it.
By articulating the proper hook angle, and having your gullet mathematically correct for the pitch, you will achieve straight grade cuts every time. YOU MUST UNDERSTAND APPROPRIATE SET AND HOOK ARTICULATION, THEY WORK TOGETHER.
THERE IS ONLY ONE WAY TO SHARPEN A BAND SAW BLADE. A stone must come down the face of the tooth, around the bottom of the gullet and up the back side of the tooth in ONE SWEEPING ACTION. You MUST maintain gullet integrity.
The gullet is NOT a trash can or dumpster for the saw dust. In fact, it is the second hardest working part of the band. A well defined gullet is like the inverted wing of an aircraft. It is responsible for the forced air flow, cooling the steel and removal of the saw dust.
If you are running appropriate set, the air is driven through the log by the gullet at the speed of the band. This causes the saw dust to be sucked out of the cut. The saw dust effectively cools the gullet by spinning around the inside and spilling over the back side of the next tooth. You MUST maintain a 40% gullet fill for proper cooling and extended cutting time.
If you sharpen just the face and the back side of the tooth, you ruin the gullet integrity and destroy the performance of the band.
THERE ARE 4 PARTS TO A BAND SAW BLADE
AND THE IMPORTANCE OF EACH PART IS:
When all is said and done, the band saw, in all its shapes and sizes, is a fundamental machine. But, as you have just read, there is a lot to know in becoming the master of your machine.
"The minimum amount of STRETCH you must apply to the body of the band to make it stable."
Always DE-TENSION the band immediately after use.
RECOMMENDED APPROPRIATE SETS AND HOOK ANGLES
|Set Per Side||Set Per Side|
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