Blade Selection & Diagnosis

It is important to know the SFM for the various speed settings of your band saw, so that you can select
the proper speed for cutting wood or other materials. Check the operator's manual of your band saw to
determine the SFM or use the following procedure:
1. Determine the RPM: check the operator's manual or clock the revolutions per minute of the
wheels with a tachometer or revolution counter.
2. Measure the diameter of the drive wheel in inches and multiply by .262 to obtain the wheel
circumference.The RPM times circumference equals the surface speed of the blade.
RPM x diameter in inches x .262 = SFM.
Note: Spring Steel Wood Cutting Band Saw Blades should never be operated at surface speeds above
3000 SFM. Carbon Hard Edge Flexible Back Band Saw Blades may be run up to 8000 SFM.
Minimum
Material
TPI Thickness
32 3/32″
24 1/8″
18 5/32″
14 1/4″
10 5/16″
8 3/8″
6 1/2″
4 3/4″
31″
2 1-1/2″
How-To’s for all Band Saw Blades
Right Wrong
Right
Wrong
Blade Width - Inches
1
3/4
5/8
1/2
3/8
1/4
3/16
1/8
Minimum Radius - Inches
7 5
1
/
2
4 2
1
/
2
1
1
/
2
5
⁄
8
5
⁄
16
3
⁄
16
Blade width is measured from the tips of the teeth to the back edge
of the blade as shown above.The instructions for the particular
machine being used should be followed when selecting blade width.
Choosing the Correct Blade Width
The number of teeth per inch (TPI) is important in obtaining the
finish desired and the proper feed rate.A coarse tooth blade
(2, 3 TPI) should be used for resawing wood and cutting thicker
stock up to 8″.A fine toothed blade (18 to 32 TPI) should be used
for thinner metals and plastics under 1/4″. For general cutting of
3/4″ wood 4 TPI will provide a fast cut and 14 TPI will cut slow,
but leave a smoother finish.
When Selecting TPI remember:
• More TPI give a smoother but slower cut
• Fewer TPI allow a faster cut with a slightly
rougher finish
• At least three teeth must be in the workpiece—
the chart to the right will help you decide.
How To Choose The Correct Number Of Teeth Per Inch (TPI)
Installing your Band Saw Blade
1. Unplug the saw, then loosen the tension on the upper wheel.With all the blade guides backed off, slip the new blade around the wheels and then tension it.
2. When you have tensioned the blade enough to keep it on the wheels,track it by turning the upper wheel with one hand while adjusting the tilt of the wheel's axis with
the other hand.The blade should ride in the middle of the rim.Never track the blade with the motor running and the cover open.
3. Next, adjust the blade guides; first the thrust bearings: upper and lower, then the left had side guides.
4. Use a square to make sure you are not pushing the blade out of line and place a piece of white paper between the blade guide and the blade to allow for clearance.
If no such instructions are provided, blade width should be determined with the following guidelines:
For Cut-Off Sawing,the blade should be as wide as the machine will allow.
The wider the band is, the straighter the cut will be. Faster feeding can be achieved.
For Contour Sawing, the blade should be as wide as the machine allows, but still
narrow enough so that it can cut the desired shape (radius). Minimum dimensions
for different cutting radii are shown on the chart at right.
Diagnosing Problems
1. Premature and Excessive Tooth Wear
•Feed pressure too light,increase it.
•Lower band velocity.
•Improper tooth selection, use a finer pitch.
•Improper break-in with new band.Velocity and
feeding should be reduced the first few cuts.
•Teeth are running the wrong direction.
Be sure teeth are pointing in proper direction.
•Incorrect saw guide insert size for the band, allowing them to strike teeth
2. Blade Vibration
•Increase or decrease band velocity. •Increase tension of band.
•Teeth too coarse for workpiece. •Increase feed pressure.
•Material not securely held.
3. Gullets Loading
•Teeth too fine for workpiece - use a coarser pitch.
•Decrease band velocity.
4. Band Stalls in Work
•
Feed pressure too great - decrease feed.
•
Teeth too coarse, use finer tooth blade
5. Premature Blade Breakage
•Thickness of blade too heavy for diameter
of wheels and speed of machine
•Increase or decrease velocity
•Check wheels for defects
•Teeth too coarse for workpiece –use a finer pitch
•Decrease blade tension •Decrease feeding force
•Brittle weld – increase annealing period, decreasing heat gradually
•Check for proper adjustment of band guides,saw guides, saw guide inserts.
and back-up bearings.
6. Blade Making Belly-Shaped Cuts
•Increase tension.
•Adjust guides closer to workpiece.
•Teeth too fine – use a coarse pitch.
•Decrease feed force. • Teeth dull.
7. Tooth Strippage
•Teeth too coarse for workpiece.
•Material not securely held.
•Too much feed pressure –reduce for good chip curl.
•Band velocity too low – increase speed.
8. Band Develops a Negative Camber
•Band is riding on saw guide backup bearing too
heavily.Adjust band for alignment on top
and bottom wheels.
•Check band wheel alignment.
9. Blade Not Running True Against
Saw Guide Backup Bearing
•If clicking noise against saw guide backup bearing,
remove burr on band.
•Check band wheel alignment.
•Check saw guide backup bearing for wear, replace if necessary
•Weld not in proper alignment. Reweld blade straight and true.
10. Cutting Rate Too Slow
•Increase band velocity. •Increase feed pressure.
•Use a coarser pitch.
11. Blade Leading In Cut
•Reduce feed pressure or rate.
•Check adjustments and wear of saw guides or rollers.
•Lack of band tension.
•Tooth set damage.
12. Premature Loss of Set
•Improper width selection - check chart for correct width for radius cutting.
•
Reduce band velocity.
13. Band Develops Positive Camber
•Decrease force.
•Use a coarser pitch to increase tooth penetration.
•Adjust saw guides closer to work.
14. Band Develops Twist
•Wrong width for radius being cut – choose a narrower blade.
•Binding in cut – decrease feed pressure.
•
Decrease band tension.
•Adjust saw guides further from workpiece.
15. Finished Cut Surface Too Rough
•Improper tooth selection – choose a finer pitch.
•Increase band velocity.
•
Decrease feed rate.
16. Band Scoring (side wear or grooving)
•Check for wear on saw guide inserts.
•Too much pressure on saw guide inserts.
•Check alignment of saw guides – be sure they are
square to front vise. Replace or clean guides.
17. Burring or Mushrooming of Blade Back Edge
•Increase tension and adjust guides.
•Check contact between blade and back edge rollers.
•Reduce feed pressure.
•Use coarser pitch blade.
•Use finishing stone.
Radius
Chart
(Not To Scale)
Blade
Width
Reprinted with permission from The Olson Saw Company, Bethel, CT C 2001