This is a home DIY parts tumbler and polisher which was made to prepare the surface of aluminium CNC machined parts prior to electrostatic powder coating. It also has many other home DIY workshop uses.
It is a beast ugly machine which was made from JUNK, but it works brilliantly!
CNC machining often leaves burrs and sharp edges on designs cut from aluminium, especially once the CNC machine cutter bits start to dull. Using a parts polisher / tumbler is an effective way to clean up these unwanted edges, knock off burrs and round metal part corners to give that professional de-burred workshop look.
The main reason for posting photos of this DIY project is to show that it isn’t always necessary to have expensive tools and equipment in the work shed to get excellent metal surface finishing results on DIY CNC machined aluminium parts. Professional looking jobs can indeed be achieved in the home workshop on the cheap. (And without hours of laborious use of a deburring tool!)
Tumbling and polishing makes a big difference to the final look of metal surfaces on DIY electrostatic powder coated aluminium parts. The tumbled metal surfaces are generally left clean and even, and are generally ready for powder coating and an oven baked finish after a quick soap water wash and scrub.
When CNC machined parts are to be left uncoated, the parts tumbler can also be used to create either a matt, pitted or scratched surface finish, depending on the type of polishing media used and the tumbling time. The parts tumbler is also great for removing rust from old and weathered steel parts prior to powder coating.
A shine polish can also be achieved by allowing parts to have more time in the tumbler with a fine, soft polishing medium.
This makes our DIY tumbler useful for polishing jewellery, stones and other minerals. Rounding off edges on small stones and milling mineral powders is also another possibility.
Admittedly, our home DIY tumbler is not the most refined looking piece of equipment in the workshop. We are not surprised either! Since the design was made up as we stumbled upon various pieces of leftover junk which was suitable to use in our Frankenstein like creation.
Perhaps the most important consideration in this rough DIY project was the motor selection. We needed a motor which was powerful enough to drive the load of the rotating parts polishing barrel without it getting hot over time, but a motor which was not so powerful that it would consume excessive electricity during the many hours of operation needed to polish parts.
The motor used for the parts tumbler was a compact 100VAC motor removed from a junk massage chair. Conveniently, this had its own motor speed controller attached, meaning we can easily control the throw of the polishing media inside the barrel. The motor runs relatively cool even when the barrel is loaded with a few pounds of parts and polishing media. It is rated at 50W, which is very reasonable.
Initially we used a motor from a 12V DC model aircraft motor starter. It worked well for short periods and light loads, but it got too hot using heavier polishing medium and eventually burnt out (almost causing a fire in our workshop, but that is another story).
Beyond the motor and electrics, our DIY parts tumbler is an accumulation of junk particle and ply board offcuts, metal tubing, a stroller wheel and an injet printer head drive belt.
We set bearings from an old skateboard in the rear tumbler barrel support bar, but later realized that having the tubing spinning in loose, well greased holes in the wood would have worked well enough (ie: as per the front drive tubing).
The rotating support bars are placed at a slightly different level to each other. This allows more barrel weight to be placed onto the front motor driven roller, resulting in more friction and more efficient barrel rotation.
The tumbling barrel itself is made from a section of tough, large diameter polypipe which has been blanked off at the ends using circular pieces of wood cut by CNC machine. An old kitchen cabinet door knob was used so one end could be used as a removable lid.
To ensure parts and tumbling media rolled, rather than slid, over the surface of the tumbling barrel when in operation, we added ‘lifters’ to the inner side of the barrel. These were made of short lengths of U shaped aluminium stripping. They were riveted to the inside of the pipe.
We have found over time that the polypipe material is perhaps a little too soft for the job at hand. It is slowly being ground away and causes unwanted dust in the barrel during tumbling. We have intentions of adding a thin rubber sheet to the inner surface of the pipe to stop this wall erosion in future.
So there you have it. An extremely useful home DIY parts tumbler built from junk, costing us essentially nothing but time tinkering in the workshop.
This certainly isn’t our most glorious looking DIY project and yes, it is extremely roughly made! However, like our DIY powder coating oven made from a filing cabinet, we had the need for this piece of tumbling equipment in the workshop to perfect our electrostatic powder coat finishes. A machine which didn’t exist in our workshop beforehand, now does!
We now have a DIY parts tumbler which can be used not only for CNC machining projects, but also for any number of different DIY tumbling and polishing tasks we may think of in future.
A DIY tumbler and polisher which works and works well!