Tumble5.jpg (43780 bytes)Tank Tumbler

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I bought everything but the terminal strip at my local "Ace Hardware" store:

  • One 5/8 inch steel rod (3 ft long so I didn’t have to cut it)

  • Two pillow block bearings (5/8 inch inner dia.)

  • Two pulleys:  1 ½ inch and 8 inch (5/8 inch inner dia.)

  • One v-belt that allowed me to put the pulleys about a foot apart (center to center)

  • Two shaft collars (5/8 inch inner diameter and a set screw to tighten onto the rod so it will hold its  position in the bearings)

  • Two slim nylon washer (I put one each between the pillow blocks and the stops to lessen friction)

  • One boat roller (5/8 inch inner diameter, 2 ½ inches outer diameter, and about 11 inches long)

  • One “dryer” power cord (my motor is 220v).

  • One terminal strip to let me connect the power cord to the motor wires without cutting the terminals off the power cord (although I could have opened the motor casing and hardwired the power cord).

Notes:

  • My pillow block bearings (the boxes they were in) looked like they have been in the hardware store since 1956, so I don’t know what luck anyone will have finding them in local stores.  They are perfectly suited for my “mounted on 2 x 4” construction, but other designs may necessitate a different kind of bearing.

  • The boat roller worked for me because the inner diameter of the roller fit the rod, and the outer diameter resulted in the tank RPM falling within the range suggested by Oxyhacker.  I could have made a PVC and inner tube roller for “free”, but the time and effort I saved was worth the $10 I paid for the boat roller.

  • My tumbler is designed to lay flat on a "Workmate", or workbench, or the floor.  Dave Dalton has a design that lets the motor hang below the roller assembly.

  • The skateboard trucks are an elegant solution for the idle roller (if I do say so myself!).  Skateboard trucks have great bearings, and the rubber bushings (which give the axels a few degrees of freedom) allow you to mount them without much regard to keeping them parallel with the drive roller (if the drive and idle rollers are not parallel, the tank could “walk” one way or the other or put undue stress on some bearings).