Craftsman 12x36 Belt And Pulley?

[Olddaddy]

I spent some time this weekend doing maintenance on my new to me Craftsman 12 X 36 lathe. It came to me with a single pulley, not the original two step. I located and ordered an original pulley which I plan to install as soon as it arrives. Question is, I planned to use a segmented belt, but I read they are directional. Since the lathe has forward and reverse should I stay with a standard v-belt? Can someone tell me the length/size based on an original pulley? I also cleaned up the wiring which consisted of a very small household extension cord spliced into the switch. I replaced it with a heavier cord appropriate to the motor, much better now!

 

[Mondo]

Hello Olddaddy:

I am not so certain that the single pulley setup on your lathe is not original. The early shipments of the 12" commercial series had a single belt between upper countershaft and spindle. Later models switched to dual belt pulleys. What is the exact model number of your lathe?

The double belts are 1/2 x 43" each. Generic part number 4L-430
The two below the bed are:
Motor to lower countershaft: 1/2 x 36 (4L-360)
Lower countershaft to upper countershaft: 1/2 x 41 (4L-410)

Segmented (adjustable length or twist-lock, etc) belts are easy to install because you don't need to dissassemble the machine to get them on. They are also very useful for emergency situations when you need to get the machine running but local suppliers don't have the length you need in stock. I have heard a rainbow of praise and criticism. They don't take a "set" from being held in one position between uses thereby reducing vibration, but they transfer less HP or torque to the driven pulley. You can make your own choice.

Some feel a "cogged" belt is better, they bend around small pulleys better and are less susceptible to taking a set between uses.
To order 1/2" wide cogged V-belts change the generic part number to AX(length) like this:
4L-430 = AX43
4L-360 = AX36
4L-410 = AX41

Spiral_Chips

 

[Olddaddy]

I am likely confused, but I thought there was a single pulley on the motor that drives the upper countershaft and is moved from step to step allowing a wider range of speeds. That's the one I am looking for info on.

 

[Mondo]

OH!! Somehow I was thinking you have a 12 x 36 Under cabinet drive model with a double belt pulley on the spindle.
What is the model number of your lathe?? I can get you EXACT information if I knew the exact model number of your lathe! Look for a name-plate on the right end or back of the bed. The number will be 101-xxxxx something.

 

[wa5cab]

Assuming that you have a 3/8" bed Craftsman 12" and original pulleys, the belt Industry part numbers are:

4L350 Motor to Countershaft
4L310 Countershaft to Spindle

I don't personally like Link-belts but don't wish to start another argument about them this morning.

On the 1/2" bed 12" Commercial models (Atlas and Craftsman) with cabinet under-drive, the original spindle belts are actually A42, which are a little over 43 inches in circumference (all of the multiple v-belts with parts numbers beginning A through E plus two digits for some unknown reason have a length or circumference that is usually a little over an inch longer than the number. Probably a pair of 4L430's would work as well but that isn't what was on my machine when I bought it new.

 

[Olddaddy]

OK, my lathe is a 101.07403. Based on this thread I need 4L350 in a V-belt. The pic shows the old pulley, on the table top and a 2" I installed just to see how much the spindle slowed down. Trouble is the belt is too short to mount the motor! The "new" pulley is due in a couple of days. I can pick up a belt in town and be ready. All very exciting!

Thank you all for your willingness to help. Robert, you have been a real friend online and via email, many thanks!

 

[Olddaddy]

I installed the "new" Atlas two step original pulley today and a 36" V-belt. Everything worked well and I was able to make four spacers for my disc brake kits, start to finish! I have a long way to go, but I am on my way.