Need outer diameters of two-step pulley on Craftsman 12" band saw

[David Hall42]

I just acquired a used Craftsman 12" 2-speed band saw, model 113.248510 but it's missing the 2 step pulley that goes on the motor. A replacement pulley is no longer available as far as I can tell. I can fabricate a replacement pulley on my metal lathe but I'll need to know the outside diameters of the two pulley steps. I was wondering, if anyone who has this same saw (or comparable models 113.248320 or 113.248440) can measure the diameters of the two step pulley on the motor and let me know what size they're supposed to be. The pulley in the manual is Key # 39 of figure 3. It is part number 816390 (Pulley, Polyrib 2 Step), not the 1.75" single step pulley that's also indicated in the list with the same Key # but a different part number. I can determine the shaft diameter and rib spacing. All I need is the diameters of the two steps on the drive pulley.

Thanks,
David

[ray hampton]

is the driven pulley a two step pulley

[David Hall42]

Yes, the driven pulley is a two step pulley.

is the driven pulley a two step pulley

[ray hampton]

Yes, the driven pulley is a two step pulley.

you may want verity this information but both pulleys should be the same sizes except that one pulley will be upside down

[Gus Dundon]

You should call the manufacturer of your band saw. If they can't have the part asap, there might be an alternative part. a

[David Hall42]

The mounting brackets and belt guard around the motor shaft won't allow a drive pulley much bigger than about 2" diameter (including the thickness of the belt) so it can't be just a reversed version of the driven pulley. Also, the single speed version of the saw has a 1.75" drive pulley and a 3.5" driven pulley which is a 2:1 drive ratio. Reversing them would result in a 1:2 drive ratio and a 4X change in the actual speed of the blade. The manual says that the digital readout of the blade speed is in one of two ranges: 2000-3000 or 1000-1500 depending on which pair of pulleys are used. That means the difference in blade speed should only change by 2X, not 4X.


The driven pulleys on mine are 3.5" and 4". Since the smaller driven pulley is the same as on the single speed version of the saw, I figured the corresponding (larger) drive pulley is probably the same as the single speed drive pulley too, so I'm planning on the larger drive pulley being 1.75 resulting in a 2:1 ratio with the 3.5" driven pulley. I figure the 4" driven pulley would require a 1" drive pulley to give me a 4:1 ratio between that pair of pulleys. These would result in a 2X speed difference between the two sets of pulleys (2:1 vs. 4:1). Both the 1.75" and 1" diameters are smaller then the 2" maximum room allowed by the belt guard.


I've ordered a replacement belt. When it arrives, I will make a pair of pulleys based on these numbers and give it a try. Still, I'd appreciate it if anyone who actually has access to this model of band saw could take a look at theirs and confirm the diameters of the two drive pulleys for me before I actually go to the trouble of making them.


Thanks, Dave

you may want verity this information but both pulleys should be the same sizes except that one pulley will be upside down

[Jerry Bruette]

If you know what the speed of the blade should be, and the rpm of the motor, all you need is some simple math to figure the ratios for the pulleys. Once you know the ratios, you can figure the diameters.

I don't think I'd fool around with making the pulley though. Unless you really want a metal shop project.

Jerry

[David Hall42]

I'm not particularly looking for a metal shop project, but I don't know anywhere to buy this two-step pulley off the shelf even if I did know the two diameters. As far as I know, making the pulley is the only way to salvage the saw. It's a ribbed belt, not a V belt so I don't expect the local hardware stores to carry an exact replacement pulley. Turning one on the lathe isn't too hard once I know the diameters. I'm pretty confident in the numbers I posted above. I was just hoping that someone could have had one around to measure to save me the trouble of doing the math, but at this point, I've already done the math so having someone measure theirs would just be a nice confirmation - not a necessity for making the new parts. Thanks to all who replied.

[Jerry Bruette]

Not sure where you're located but you could go to a local Gates belt distributer and ask them about micro groove pulleys. Our local distributer is Motion Industries.

I'd take the pulley you have along so they could verify the size and such. They're very helpful. Or you could google micro-groove pulleys or sheaves. Jerry

[Flip Hawkins]

I just acquired a used Craftsman 12" 2-speed band saw, model 113.248510 but it's missing the 2 step pulley that goes on the motor. A replacement pulley is no longer available as far as I can tell. I can fabricate a replacement pulley on my metal lathe but I'll need to know the outside diameters of the two pulley steps. I was wondering, if anyone who has this same saw (or comparable models 113.248320 or 113.248440) can measure the diameters of the two step pulley on the motor and let me know what size they're supposed to be. The pulley in the manual is Key # 39 of figure 3. It is part number 816390 (Pulley, Polyrib 2 Step), not the 1.75" single step pulley that's also indicated in the list with the same Key # but a different part number. I can determine the shaft diameter and rib spacing. All I need is the diameters of the two steps on the drive pulley.

Thanks,
David

Hi David,
I have the same saw that I also recently acquired. My saw was making a bad clunking noise. Upon examination, I found that the motor pulley had been installed without a key in the keyway slot. It had been operated that way and the pulley was badly worn on the inside, the motor shaft was also damaged. Not having access to machine tools I decided to have a machine shop do the repair. It entailed reboring a larger hole in the pulley, truing up the motor shaft and then making a sleeve to fit the two together. I just picked it up yesterday and I can provide you dimensions after I get home tonight. Let me know if you still need them.

Flip