Southbend METAL-CUTTING BANDSAW SB1019 - Manual (Page 27)

For Machines Mfg. Since 8/09 Model SB1019
-25-
O P E R A T I O N
blade selection
Blade Tension
Proper blade tension is essential to avoid blade
vibration, twist, or wheel slippage. A correctly
tensioned blade provides long life, straight cuts,
and efficient cutting.
The three major signs of incorrect blade tension
are: 1) The blade stalls in the cut and slips on the
wheels, 2) the blade frequently breaks, and 3) the
bandsaw does not make straight cuts.
To tension the blade on the bandsaw:
1. Make sure the blade is tracking properly.
2. DISCONNECT BANDSAW FROM POWER!
3. Loosen and slide the blade guide as far out
as it will go, then tighten it down again.
4. Turn the tension knob in Figure 22
clockwise to tighten the blade or clockwise to
loosen the blade.
5. Tighten the blade until the tension indicator
moves into the green or center section of the
indicator.
Figure 22. Adjusting blade tension.
Blade
Tension
Knob
Blade Breakage
Many conditions may cause a bandsaw blade to
break. Some of these conditions are unavoidable
and are the natural result of the stresses placed
on the bandsaw; other causes of blade breakage
are avoidable.
The most common causes of avoidable blade
breakage are:
• Faulty alignment or adjustment of the blade
guides.
• Forcing or twisting a wide blade around a
tight radius.
• Feeding the workpiece too fast.
• Dull or damaged teeth.
• Over-tensioned blade.
• Top blade guide assembly set too high above
the workpiece. Adjust the top blade guide
assembly so that there is approximately
1 ⁄
8
"– 1 ⁄
4
" between the bottom of the assembly
and the workpiece. Understand that with
smaller workpieces, this may not be possible.
In these cases, simply adjust the blade guide
as far down as possible.
• Using a blade with a lumpy or improperly
finished braze or weld.
• Continuously running the bandsaw between
operations.
• Leaving the blade tensioned when not in use.
• Using the wrong blade pitch (TPI) for the
workpiece thickness. The general rule of
thumb is to have no fewer than three teeth
in contact with the workpiece when starting
a cut and at all times during cutting.
• Air in the hydraulic system, causing the
headstock to "hop" on the workpiece.
• Stacking workpieces for multiple cuts at
once.
!
Tension Indicator