Setup of two speed pulleys on vintage Delta band saw

[roger wiegand]

This saw is in the museum where I volunteer-- it's both part of the machine shop display and a tool we use fairly regularly. It's a two speed saw, but the gearbox is not the (later?) one that changes gears, but rather more like a clutch that engages or disengages the upper or lower pulley. We are confused by the pulley setup. It looks as though there should be maybe two belts on it, one to the lower pulley for the slow metal speed, one to the upper for the fast wood speed. This would work if both belts were the correct lengths, which they are not. The longer belt is loose and there is no obvious adjustment mechanism other than moving the motor, no way we can see to adjust the belts independently. I'm suspicions that the four step pulley on the motor isn't original-- it's not possible to correctly align the wood speed belt with the belt in the largest groove, the only one that is close to tight enough to drive the saw, albeit at a slower speed than optimal. I can find the serial number but not a model number.

Because it actually gets used for both wood and metal in this shop we'd like both to work well. If someone knows this saw or can tell me the model number so I can search more successfully for a parts diagram I'd appreciate it.


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[John TenEyck]

I have a Delta like that. You are correct, there is a clutch in the upper wheel that engages that wheel or the one in the middle, depending upon whether it's pulled out or pushed in. Strange, there is no such engagement knob on yours like on mine. Now that I look closer, it looks like that mechanism might be near the mid pulley, yes? In in any case, you need two different belts, one for upper to motor pulley for wood cutting, and a shorter one for the middle to motor pulley for metal cutting. There must have been some clever setup so they could be changed w/o having to move the motor, but mine came w/o a motor, and it wasn't obvious how to do it, so I made a motor mount that allows the motor to be picked up a few inches to change the belt.

I rarely use it for metal cutting, but when I do it works great.

John

[roger wiegand]

John-- does yours have the four step pulleys on the motor and lower saw pulley? If so, which groove do you use for sawing wood? It seems as if you can leave both belts in place and switch speeds with the clutch knob, as it lets the one that is not in use freewheel. Is that what you do? Thanks!

[Tom M King]

Mine had the four step pulley on the motor, but when I changed the motor to one that had a larger shaft I had to change to a single pulley since I only use it for wood. I've never noticed the other parts of the mechanism. Mine is a Delta/Milwaukee but I forget when it was made.

[John TenEyck]

John-- does yours have the four step pulleys on the motor and lower saw pulley? If so, which groove do you use for sawing wood? It seems as if you can leave both belts in place and switch speeds with the clutch knob, as it lets the one that is not in use freewheel. Is that what you do? Thanks!

Here's what mine looks like, Roger. Yes, 4 step pulley on motor and lower saw shaft/pulley. And you can see the clutch knob as part of the upper pulley assembly. Out is engages the top shaft/pulley, in the lower saw shaft/pulley.



You most likely are correct that the correct size belts could be left in place all the time, as the clutch would engage the pulley desired and let the other freewheel. I just use two different belts. I use the highest speed combination for sawing wood. I changed to a 1.5 hp motor when I got the saw which runs at 3450 rpm. I had to replace the bottom pulley set to fit the shaft, so the speeds are different than on the OE setup. I think it runs around 3500 fpm. Twenty five years that way. I don't think speed is all that critical as long as it doesn't create vibration. 2500 to 3500 would be a good range for cutting wood.

John

[roger wiegand]

Interesting-- the clutch on ours is operated by the lever indicated, not the knob at the center of the pulley. A link belt might be a really good idea for us, as the motor doesn't pivot.

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[John TenEyck]

I suspect your saw is an earlier model than mine.

I fabricated a motor mount that allows the motor to be lifted vertically. That permits easy changing from one belt to the other. The weight of the motor provides the tension on the belt.

John