FAQ: Troubleshooting | Detroit Band Saw

FAQ: Troubleshooting

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My band saw is cutting out of square. What do you suggest I look at?

Take a look at our Problems and Solutions Reference Guide located on our website. If you need further assistance, feel free to contact customer service.

Which type of band saw blade do I use?

Carbon FlexBack – Low cost blade for plastics, woods, and non-ferrous applications.
Carbon HardBack – Greater rigidity than flexback allows up to 25% more performance
Bi-Metal M42 – Resists heat and wear at higher speeds and feeds
Carbide Tipped – For use with highly abrasive metals and non-metallic composites
Set Tooth – for nonferrous foundry applications such as cutting gates and risers, some exotic applications
Triple Chip – for cutting exotic metals and for high production applications, some nonferrous foundry.

Which tooth pitch should we use?

Number of teeth in the cut:
Minimum – 3 teeth in the cut
If there are too few teeth in the cut, the teeth can straddle the work piece, which can cause stripping.
Maximum – 24 teeth in the cut
Too many teeth in the cut may cause the gullets to “overload”, because there is not enough gullet capacity.

The “optimum” TPI is 6 to 12 teeth engaged in the cut at one time
Conditions that influence pitch selection:

  • Soft materials: Require fewer teeth and more gullet capacity (Aluminum, Copper, Bronze, Carbon Steels)
  • Tough Materials: Use a moderate amount of teeth in the cut – in the 12 to 18 tooth range (Inconel, Hastalloy, Waspalloy, Monel, Steels)
  • Hard Materials: Use more teeth in the cut – in the 18 to 24 tooth range (D-2, Die Steels, Stainless Steels)
  • Machine capabilities: constant feed machines can use a coarser pitch, whereas gravity feed machines typically require a finer pitch
    Production or blade life:
    1. For production cutting, use tooth pitches near the coarse end of the range
    2. For good finish or smoother cut surfaces, use finer teeth
    3. For best blade life, run in the middle to the fine end of the recommended tooth pitch range

What blade speed should we use?

  • Material Machinability Rating – The lower the machinability rating the slower the band speed will need to be.
  • Blade Selection – The cutting edge (tooth tip) of the blade will govern the speed at which the blade can run (FlexBack = Slowest Cutting, Carbide = Fastest Cutting)
  • Cutting Noise / Vibration – Cutting noise or vibration is a killer to a cutting edge – if either is present, the speed must be decreased
  • Coolant / Cutting Fluid – If the coolant is adequate, use the standard cutting chart speeds. When cutting dry, reduce the speed by 40-50%

What is the relationship between feed and speed?

  • Feed, Speed and Tooth Pitch are directly related.
  • To change the cut result, change only one variable at a time.
  • Increasing the Work Size will decrease tooth penetration.
  • A larger Tooth Pitch will increase tooth penetration.
  • A smaller Tooth Pitch will decrease tooth penetration.
  • Increasing the Blade Speed will decrease tooth penetration.
  • Reducing the Blade Speed will increase tooth penetration.

Why do we need a cutting fluid?

Lubricating the cutting edge will reduce the heat that is generated by cutting friction – too much heat in the cut is one of the main reasons for blade failure.

  • A flood of coolant helps wash the chips from the gullets
    • Chips become work-hardened in the cutting operation
    • If chips are dragged back through the cut a second time, they can damage teeth
  • A flood of coolant helps cool the blade’s cutting edge and saw guides, extending blade life.

Remember: flood coolant whenever possible and only use coolant where chips are present – do not use coolant on materials that produce a powder, such as gray iron.

Why do we need to break a band saw blade in?

  • New, sharp teeth are more fragile than lightly honed teeth
  • Break-in hones the teeth and helps make all teeth the same height
  • Proper break-in results in less blade stripping and longer blade life

Break-in Procedure:

  1. Set proper blade speed for the machinability and size of material to be cut
  2. Reduce the normal feed rate by approximately 50% of the regular rate for the first few square inches
  3. Watch the chips
    Small flakes = Insufficient feed
    Heavy blue chips = Excessive feed
    Spring curled no color = Proper feed rate
    (During break-in, it is important that the band always produces chips)
  4. As you break-in the blade, graduate the feed rate to 100%.

To learn more about the importance of blade break-in, please take a look at our blog.