From: null@void.com   
      
   "Jim Wilkins"  writes:   
      
   > "Richard Smith"  wrote in message news:m134f1egx2.fsf@void.com...   
   >   
   > Gerry  writes:   
   > ....   
   >> On Sun, 23 Mar 2025 18:13:23 -0400, "Jim Wilkins"   
   >>  wrote:   
   > ....   
   >   
   > At 0655 I'm here at my table thinking of ways to have the drum spin /   
   > turn.   
   > Reckon it's going to be about 60RPM.   
   >   
   > It's likely going to have to be very improvised.   
   > Thanks for the encouraging comment to say there must be a way.   
   >   
   > Regards,   
   > Rich S   
   > ---------------------------------------   
   >   
   > Perhaps you could suspend the drum from two (used?) automotive   
   > serpentine belts driven by the upper shaft. The motor drive on my   
   > lathe has a vee pulley and belt on the motor driving a large flat   
   > pulley, the friction of the softer inner rubber is enough without side   
   > walls. A vee belt normally grips because when bent the inner rubber is   
   > forced to expands against the pulley walls by the inelastic fibers in   
   > the outer part.   
   >   
   > Serpentine belts also have softer rubber on the inside. Rubber alone   
   > without fiber reinforcement gives jerky start-stop motion.   
   >   
   > The weight of the drum might give enough friction on the upper shaft   
   > to drive the belt. If not the shaft could be roughened or the belt   
   > pressed tighter with an idler or a heavy rod on top. I turned pulley   
   > grooves to match a serpentine belt with a 40 degree angled cutting   
   > bit.   
   >   
   > More than one turn of rope on the drum will walk sideways. Multiple   
   > turns of string is simpler than a long splice though maybe not   
   > better. It does wrap around a small drive shaft more closely. It can   
   > be made stickier with rubber cement. Friction tape on the small shaft   
   > might last long enough for experiments   
   >   
   > I think I'd grind the torch-cut rod ends smoother and bolt the strakes   
   > on at their ends to make them easy to swap. Using angle iron would   
   > reduce the strain on the screws by widening their base and eliminate   
   > tapping the strakes. Screws alone protruding in a little more than the   
   > rod radius might lift the rods while leaving the rocks at the bottom.   
      
   I've seen videos of "artisanal" gold mining operations in South America.   
   The videos are/were motivated by trying to find an alternative to using   
   mercury to extract the gold, but anyway...   
   They show sheds with cast concrete mountings for lines of ball-mills -   
   drums about 800mm diameter.  Drive is from a line-shaft by belts running   
   one to each mill.  The mill is on an axial axle, so not suspended from   
   the belt.   
   For what it's worth...   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)