bandsaw motor speed

[wallace]

I was in the workshop yesterday cutting some 5" maple on the bandsaw when the blade started to slow. On checking the motor belt tension I noticed it was too slack. The previous owner had converted it to single phase and fixed the motor so I could not change the tension. I tried to reverse the cut and ended up snapping a newish tuffsaw blade The saw is a startrite and I'm going to reinstate a motor in the correct place so I can tension the belt properly. I have a 2hp motor to improve the performance. But I'm not sure about bandsaw speed. Is there an optimum speed for cutting or does it vary on work?
Mark

 

[CHJ]

First thing you need to consider is the number of poles in your motor and consequently its speed.

A 2 pole motor will run at 2850 RPM
A 4 pole motor will run at 1425 RPM.

A basic guide to BLADE SPEED is:
For hardwoods, some plastics and non ferrous metals 440-450 Metres per minute.
For all other timber 900-950 Metres per minute.

Therefore your Motor pulley diameter needs to be paired with your motor speed to provide a final blade speed somewhere near those figures.

 

[Argus]

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What sort of Startrite saw do you have?

.

 

[wallace]

Thanks Chas, the motor is rated at 1400 so with your figures should be easy to work out. Presumably thats why the saw has the two sizes of pulleys, for differant woods. I thought quicker would be better for hardwood. The saw is a 352, looking at it. it looks like the original motor is supposed to be mounted upside down? I've just remembered that the saw has a chart on the back stateing speeds for differant stuff (hammer)
Mark

 

[CHJ]

.... I thought quicker would be better for hardwood. .....

I think it's more down to Blade Quality and Power of machine for the hardwood. Pulley ratio obviously adds more torque at lower blade speed.

Mine (SIP 14") rarely gets moved to lower speed.

 

[Argus]

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There was a related thread about 18 months ago about the pulley sizes (hence speed) of a 352.

post571721.html?hilit=startrite#p571721

There aare variants, but I have a PDF manual if you pm your e mail address. It's fairly basic,but better than nowt.............. It does contain rudimentary info on cutting speeds and tensions. Mine has a tension table on the back.

There are two motor speeds that crop up, depending on your motor - either 2 pole (nominal 2800 rpm) or 4 pole (nominal 1400 rpm). For some reason startrite supplied both........
The drive speed is determined by the motor pulley size, so it's important to get the right pulley/motor speed combination.
For the old thread I measured my pulleys fitted to a 4 pole motor to deliver the design speeds - it is the 6 th post down.

The motor is slung and tensioned on a pivoting cradle at the back and is a pig to get at.


All best

 

[RogerP]

My Axminster AWHBS350N 14" Band saw has speeds of 600 & 720 m/min (I've never understood why they are so close) I always use the higher speed and I've not had a problem even though it's only a 1HP motor.

 

[dickm]

At some point, Alan Holtham said that he only ever used the lower speed on his 352 (like the Axi, the two speeds are not that different). Mine was converted from 3-phase using the original pulleys; can't remember whether it's now got a 1400 or 2800 motor, but it seems to work fine on the lower speed. Could check details for you if it would help.