Section IV : Pulleys and Belts

Coal Breaker Pulley

This is the pulley on the Coal Breaker itself. I am designing for the larger breaker which requires 45 hp. I have a page on crushers down to 10 hp on my Coal Breaker page. You can the assortment of breakers from 10 HP with a 10 ton per hour capacity up to the 45 HP breaker with a 83 ton per hour capacity.

The pulley is 64″ in diameter with a 12-1/2″ face for a 10″ belt. It has five arms and an opening for a 3″ shaft. I changed the opening to 6″ to match the shafting on my Coal Breaker. This was calculated as you can see below.

3D printing : I am putting progress on this on the bottom of the page.

Data

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• (Pulley Circumference in Feet x RPM)
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3D Printing

• Plan: These calculations were generated for a “Real-World” pulley. To 3D print these in 1:48 requires some modifications. The Rim Edge Thickness is shown as .205″ which scales to 0.11 mm .. way too thin. I increased this to 0.3 mm .. which should be ok. The same with the arms .. except I will just say .. “may” be ok. If there are problems .. which would be related to simply the thickness of the parts I will enlarge them until the pulley prints without problems.
• Results – Test Print #1: The first test print actually went pretty well. I printed it flat without any tilt .. sometimes you CAN break the rules. I did not want any support scars on the face of the pulley.
  • There was sag between the supports as I had too few spaced too far apart. You can see on the far side where the print pulled away from supports. The hole in the center was a tight fit on a 1/8″ rod .. looking at the CAD I found I had forgotten to pad that hole a bit so for the next print I enlarged it to 0.128″ dia.
  • I added the supports manually for this test. The next one I will use Chitubox to add supports