Tuesday, June 14, 2011

Tumbler Plans Introduction





I built my tumbler after considerable research and planning and I use it every day and I am quite happy with it's operation. Like most other machines it's construction process and it's operation is inherently dangerous and requires considerable skill to mitigate risk. This information is made available as an explanation of "how I did it" and is not intended to be a recommendation to others. It is offered without charge but if anyone finds such information useful and wants to send me a few bucks to keep me encouraged about making this sort of post - Super!

Back in September 2010 I published an article on using the tumbler. Now I will post illustrations of how it is constructed. My current machine was my design based on three previous experimental machines but I paid another local company to build it. If I ever need another version I plan to build it myself. I like the feeling of confidence I have when I have done all the construction and fully understand the piece and have no hesitation about makings modifications if needed. Coincidentally the welder who constructed the machine later came and did some work for me so he got to see his creation in operation.

I’m just starting the sixth year of using my tumbler. So I think I understand its’ capabilities and limitations pretty well now so I felt it was time to share my experience.

When the tumbler was delivered to my studio the chain hoist moved it from the truck to a concrete pad outside the garage door space. It only took a few runs to conclude that noise was going to be a problem and an indoor location was necessary.

After further use I made a few modifications. First I added base plates on the legs so they could be anchored to the concrete floor with screws. Next I added the square lugs on the non-motor end plate and made a wrench to aid turning the tumbler so the doors are rotated to the top for opening. A swing arm post was added with an electric hoist for lifting a secondary tumbler which was used for tumbling smaller delicate items with smaller aggregate. The original motor mount eventually broke and was replaced with a more sturdy one. I glued on some foam insulation to see if it would suppress noise and found it was essentially ineffective. Finally the catch pan and tarp cover was added to help contain scale, dust and other debris.

Design features:
The Frame: Heavy duty is self evident.

The Motor and Mount: As sturdy as possible. The powerful motor, chain drive and heavy load creates tremendous start up forces which broke the original mount.

The Cylindrical Drum & Axels: Sized for the majority of the type work I do. It might be nice to have a 10' length so all nominal stock could be tumbled to remove mill scale and burrs before storage but that would add a lot of cost and greatly enlarge the space required.

If I built another one the reinforcing ribs would be placed on the outside of the cylinder and I would have a center hole milled in the non-motor end axel to accommodate a vacuum fitting.

The Doors: I think they need to be a balanced pair as the weight and leverage of a single large door tends to rotate the cylinder and dump the contents. The heavy duty draw latches have worked well.

The long continuous hinges became very stiff as the cylinder, ever so slightly, ballooned with use. I cut the pintle rod in two places on both hinges with a zip disc and got some release. Periodic oiling helps too. I decided to accept enough stiffness to require me to use a slotted cheater pipe tool to pry the doors open and shut. This design has the advantage that a door won't fall closed and perhaps catch a finger and they will remain in whatever position I select.

The Swing Arm Hoist: Originally built to assist some heavy lifting, the electric hoist has been moved to the overhead frame on the acorn table and the swing arm is not currently used.

The Clamshell Dust Container: This helps contain dust and debris in the bottom catch pan and floor area in the foot print area of the tarp. A vacuum system hooked to to the timer might be nice.

The Aggregate: Steel is the only thing which has worked for me. I keep about 100 pounds of punch drops, carbon steel balls, and miscellaneous short drops aboard all the time.

Noise Suppression: Probably not practical. Perhaps some type of replaceable interior rubber liner would help.

Next - more of the details.

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I don't often check for blog comments, so the best way to contact me is directly: at ottercreeksmith@gmail.com or djedwards@cableone.net