Troubleshooting for Wide Band Saw Blades
- Material of wide band saws manufactured by PILANA has a guaranteed tensile strength 1450+100 N/mm2, phosphorus and sulfur content if less than 0,02%.
- While cutting soft wood we recommend to use wider tooth pitch.
- While cutting hard wood we recommend to use smaller tooth pitch.
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Requirements for band saw
- band saw blade and wheel must be constantly oiled during cutting performance. Chips must never get between blade and wheel.
- Cutting period must not exceed 2 hours.
- After this working period blade should be re – sharpened and left aside in static condition for 24 hours.
- It is undesirable effect when left any allowance among bearings and maximum run-out should not exceed 0, 03 mm of radial value and 0,1 mm for axial value.
- Straightening device should also be kept in perfect condition to enable thermal expansion of blade.
- Blade usually expands during the cutting application by 1 mm and temperature increases by 15 °C.
- Wheel setting should always have the same recommended values and if wheels are worn out, it is necessary to service them (radial turning).
- Tooth setting should be done “left-right-straight” for cutting soft wood and “left-right” for cutting hard wood. Only tooth tops should be toothed up to max. 1/3 height.
- If tooth height is 10 mm, toothed part must not be over 4 mm.
Tab of recommended equalization of wide band saw blades:
| Wood type | Tooth pitch [mm] | Overlap of teeth [mm] | ||
|---|---|---|---|---|
| Set saws | Stelitte-tipped/tampered saws | Set saws | Stelitte-tipped/tampered saws | |
| hard | 25 - 30 | 35 | 0,3 - 0,4 | 0,3 - 0,4 |
| frozen | 25 - 30 | 35 | 0,5 - 0,6 | 0,5 - 0,6 |
| soft | 30 - 35 | 40 | 0,6 - 0,7 | 0,6 - 0,7 |
For optimum grinding of our band saw blade we recommend grinding wheels type A99B(a98) 80 K – for roughing it is also possible to use 60 K.
For grinding of stelitte band saw blades we recommend to grind only stelitte part, do not grind the body.
Recommended hook angles
| Wood type | Set saws | Stelitte-tipped/ tampered saws |
|---|---|---|
| hard | 15 - 22° | 18 - 22° |
| soft | 25 - 27° | 26 - 28° |
All angles should be measured with sextant. Do not rely on setting of grinder. Grinding disc can slipped hook angle which could cause grinding a wrong angle than required. Cracks between the teeth can occur in grooves made by grinding disc. That is why it is necessary to grind very fine, do not over heat the material, wet – grind with surface roughness Ra < 3,2.
Accuracy in band saw guiding – if inaccurate band saw guidance a wider tooth setting is needed. When cutting across the grin smaller tooth setting is better. If we do use a wider blade, we choose wider tooth setting. Tolerance for tooth setting for the same blade is ± 0,05 mm.
| Most common problems | Probable reason | Solution |
|---|---|---|
| Tooth cracking | Allowance in bearings of wheels | Adjust the allowance, change bearings |
| Dirt between wheel and blade | Clean the wheels, service regularly | |
| Long cutting process without break | Use blades max. 2hours / leave resting for 24hours then | |
| Too long grinding | Grind very smoothly, wet grind, surface roughness max. Ra < 3,2 | |
| Blade is dull | Sharpen, measure | |
| Tooth breaking off | Hook angle is too big | Lower the hook angle |
| Tooth setting is too big | Lower the tooth setting | |
| Uneven cutting | Small hook angle | Make bigger hook angle |
| Wrong choice of tooth pitch | Choose the right tooth pitch | |
| Bad condition of straightening device | Check the machine by expert / fix | |
| Asymmetrical setting/ press | Adjust the grinding machine |
