High-Speed Mod for Thumler's Model B, Green Silicon Carbide

Guys lets try and stay on focus. The simple mod will work on anyone's rotary tumbler (to speed up/ slow down) which will enhance control, and your general experience.
Pulley size change is the ideal permanent solution. Tape (non-adhesive rubber stretch), or other ideas suggested above will all work for the Drive roller mod, which is incredibly easy to do.
Also you will be freed from from the one-speed-fits-all assumption, which might apply to someone beginning but not to an advanced tumbler, or someone wanting to improve their techniques. If your happy with the one-speed system, as it is tried tested and proved and works for you, then leave it alone.
I'm sure anyone tumbling chalcedonies (agates, jaspers) will thank me later.
Very expensive high-end tumblers have adjustable/variable speed controls for this reason. I don't like these, as the motors wear out much faster.

My next mod will show you how to slow down your UV-10.
The UV-10, or all Thumler vibes run at 3000 VPM, which IMHO is perfect for hard stones, but too fast for soft stones.
Its also too fast for polishing. It works, again in general. A lot of the hazing I have read about in these this forum is actually from too much action on the vibe. I previously killed soft stone loads during the superwash stage (usually after 1000 Al Ox ), as there is nothing to protect the stones (thickening agents). Running the vibe at 1/2 the speed eliminates 90% of the problem.
Again, like I said above, high end vibes are offered in Variable Speed models, for user control. The issue is the motor wears much faster.

My Thumler's model B's spin 22 RPM empty, and 18-20 RPM full.
While this speed works for all round general use, it is not ideal for Hard Stones [H.7 - (chalcedonies: agates and jaspers)]
I want my hard stones to spin at 32 RPM, in order to get the same results in 1/3 time.
I would also advise using GREEN 46 grit SiC or G46SiC.  The lower grit size, and the increased speed should cut your grind time by at least 40%, and decrease your abrasive use, since you will have less grinding cycles.  If you really want to speed things up, go hard-core, and get Green 17 grit SiC or G17SiC (50% decrease in standard tumbling times).  
I would also like to "introduce" to the tumbling world (RTH) Green Silicon Carbide.  Green is a higher quality Silicon carbide, more pure crystals which are harder and more aggressive.  You can get by perfectly fine with using black silicon carbide, but it will be less efficient.  In General the green is ***15-30% more efficient, and ***15-30% more expensive. ***I only recommend GSiC for harder stones, and would consider quartz fine with black SiC.
Since time is money, anyway I can speed up the process counts.

Thumler's model B mod:
The simplest way to speed up the process is to mod the drive shaft by adding diameter.
I first used black electrical tape. It worked well, but wears out over time, and needs to be adjusted every few months to keep the speed.
Then, I thought of hockey stick tape.  Brilliant...Until i put it on... nightmare.  It gets so gooey, wow, I don't even know how I recovered by somehow removing it.
Finally, I switched to non-adhesive, self fusing rubber tape and all is well.
1" x 6'-8" perfect for one application, and mine as not needed to adjusted in the last 3 months, but did drop to 30 RPM recently, so perhaps the tape has leveled a bit, and requires a slight addition to get back to 32 RPM/
I used 34" of tape wrapped around each roller of the Drive Shaft.
Drive Shaft Mod (see video) 
I was prepared to add, more, but my speed ended up at my desired 32 RPM.  Sometime it takes a few minutes to get up to speed!
Since you are adding more force to the motor, you might need to help it start, and or run the tumbler first and then place the barrel.
The motor will run a bit hotter, and you might decrease its life proportionally with the increased use.  Mine has been Modified since Aug 2014, and runs pretty much 24/7 without an issue. Yes you can get the same results by increasing the pulley as well, but don't have the speed control by adding or subtracting tape.

I have an extra drive shaft, so if I need to switch back to standard speed, I only need to switch out the drive shaft, and have a 2 speed rotary tumbler.  This gives me much more control of my product, and much more use and pleasure of the machine.

**If you have the High-speed model B, you already have the perfect machine for harder stones.  To slow down your tumbler for quartz and softer:
Get an extra drive belt, and decrease diameter of the foam rollers (for example sand them down), or ideally replace the pulley with a smaller one.


If your tumbler wonders to either side, which is a general problem with this design (especially if not running flat), you can add a washer below the bottom of the side it is wandering towards to correct. Thanks to Connrock for that idea, and you can see this in the video as well with my standard model B (left side, Barrel #1 was wandering to the left, so I added a washer below the right side to correct. 

 Enjoy!
Does anyone have hard data on Green SiC Vs. Black SiC spinning MOHs 7 or harder at very coarse grit, like 36 or 60. I have seen significant results with black 36 or 46-70  Vs. 60-90, etc. at higher barrel speed with hard agate (like Montana) ...any thoughts?