Super Rock Tumbler
After running a tumbler for over a year, practically non-stop, I got to see where the wear points and heating issues were coming from. I sat down with some paper and drew up what my dream tumbler would be. Some of the specifications and major improvements over my Harbor Freight 6lbs model would be:
All bearings to be replace nylon bushings
Adjustable roller spans
The first draft of the design...
CAD cleanup for the build. The structural elements are based around the stock I already had in the shop.
Bearings are surprisingly expensive. After researching and pricing bearing that fit the existing tumbler shafts, I found the average price was around $12.00 each. $48 plus shipping isn't a bank-buster but it already set the materials price high enough to ruin the whole DIY vibe. It hit me two weeks later... images of my old friends the dumpster roller skates! They fit perfectly!!!! Oh, as an added bonus, I looked up replacement roller blade bearings and the prices on those things were really cheap ($4) per unit as compared to buying from a bearing company or McMaster Carr.
Test fit on the shafts
Starting the sheet metal work. Rollerskate/blade bearings are a perfect 7/8" OD, just begged the
shop manager at the school to punch my holes for me in exchange for some lunch.
1/2 square stock frame almost done. Note : If you are not comfortable or lack welding and other metalwork
tools, fear not!Thiswhole project can be done with simple scrap wood or hardwood molding stock from
Home Depot. You still have to dig up some rollerskate bearings.
My son assembling per the plans I printed.
Test-fitting the brackets and components. Already there's an issue with the belt being too tight. I'll slide over the
vertical bracket towards the large pulley with a new set of holes.
After a few years of running - my second flaw ( the first was the vibration that allowed the frame to "walk" across the table over a series of hours - solved with the 1/2 racquetball ball feet) is that older belts seem to break easier with the small pulley diameters. I did find large diameter pulleys at McMaster Carr, but tre expensive... DIY time.
Working on a fan mount before starting on a sound-proofing enclosure.