Jan 15, 2021 Thumlers MP-1 Rock Tumbler Detailed Review. Thumlers make some serious tumbling equipment. The MP-1 sits somewhere between the toys reviewed on our site made by other companies and the Thumlers a-r1 model (also reviewed).. We would class the MP-1 as a top of the range entry level model to the world of tumbling. Thumlers Heavy Duty Rotary Tumbler is a professional quality unit extensively used by serious hobbyists laboratories schools and industry for an unlimited variety of tumbling and mixing operations. The high-speed 1550rpm motor will polish metal or deburr as fast as a vibrating motor.