From: muratlanne@gmail.com   
      
   "Richard Smith"  wrote in message news:m1free83oi.fsf@void.com...   
      
   > I've arrived at a new mechanical-part design for the rod-mill where   
   > drive is through the wheels the shell rotates on.   
      
   I have an old Thumler like this whose (only) advantage is simple   
   construction.   
   https://rocktumbler.com/thumlers/model-ar-2.shtml   
      
   The drive has more authority to lift the balls/rods/pebbles with both roller   
   shafts belted together, and friction tape etc on the drum. The plastic shaft   
   bearings are a type used on garden equipment, the rollers can be soft rubber   
   tubing or if larger to clear the end cap have tread cut from a bicycle inner   
   tube. The drum needs some restraint from shifting too far endwise. Perhaps   
   the end caps could be rubber caps for plastic drain & culvert pipe which   
   would also aid traction and might dampen noise. You could bolt clear plastic   
   over central holes in them to observe and adjust the action of the rods.   
      
   Since the ribs need to lift the rods more than the charge, they could be   
   replaced by pairs of screws from outside, preferably in tapped holes. Nuts   
   and washers on the inner end could raise the rods higher before they roll   
   off.  If screws don't work by themselves they could attach metal rib strips   
   such as sheet metal angles trimmed and bent for best performance. This would   
   make stirring the charge and dropping the rods easily and independently   
   adjustable.   
      
   Screw hole locations could be marked on paper whose length equals the drum   
   circumference. Aligning the ends of the paper positions the holes for center   
   punching as accurately as the paper layout. You could start with one pair   
   and observe where a rod lands when dropped from as high as practical, to   
   space the others away from the landing area.   
      
   This gives the general idea of how to divide the length of the circumference   
   into equal parts by angling the ruler.   
   https://www.woodmagazine.com/woodworking-how-to/shop-tips/layout   
   measuring-marking/get-equal-spacing-in-seconds-with-no-math   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)