Rock Tumbler

This is a very cheap rock tumbler.

You will need 4 skate board bearings, a motor, a power supply and some 1mm thick rubber sheet, all available off eBay.
Bearings I got here:
https://www.ebay.co.uk/itm/10pcs-Ball-Bearing-608ZZ-Bearing-Deep-Groove-Ball-Bearing-8mm-22mm-7mm-Useful/332464460888?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
£2.98 for 10, 29.8p each x 4 = £1.19
The rubber sheet I got here:
https://www.ebay.co.uk/itm/SOLID-RUBBER-SHEET-BLACK-1400MM-x-1MM-Leatherette-Commercial-Grade-Polymer/272537621896?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
I didn't use much, cost not worth mentioning.
The Motor I got here:
https://www.ebay.co.uk/itm/Miniature-motor-365-round-Motor-DC-12-24V-3000-RPM-6000-RPM-DC-Motor-DIY/401295531499?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
£2.27
The PSU was the most expensive, I bought this from Maplin, set to 12V:
https://www.maplin.co.uk/p/6w-multi-voltage-acdc-power-supply-xx09k
£9.99
So, less than £15 all together for a finished rock roller.

I took off the PSU connector and soldered the wires directly to the motor, turn on and off using mains switch on wall socket.
It runs at about 1 revolution per second.

Rubber sheet is used inside end caps of drum to seal (make it water tight), used inside and outside drum (to quieten), used on rollers and outside of lids (grip).
The drive band is created by mixing up oogoo, putting into mould and letting set.
Each band appears to last about a month, been trying to create drive bands from rubber sheet, but not been successful yet.
I've also created a plywood box which is carpeted inside and out with carpet tiles to further quieten it, but I'm not totally convinced this works.

I've had 2 of these running for 24 hours per day, 1 week for each stage.
For details and pictures details of rock rolling still in progress, see here:
http://trevmhomers.blogspot.co.uk/2017/12/rock-tumbler.html
I still have not completed a full set of stones polishing through 4 stages to nice and shiny.