RUMBLE or Shaking Machine. - This is a contrivance sometimes used for polishing small articles principally by their attrition against each other. The rumble is a cylindrical vessel with a side door for the introduction of the work, and is generally made to revolve as a churn by a winch handle or pulley, or is shaken endways by a crank in imitation of the mode of cleaning nails in a sack, and it is thence called a shaking machine. The following are some of the uses of the rumble in mechanical works: -
For brightening iron tacks previously to their being tinned, water is in this case introduced.
For polishing steel pens with sawdust after they are hardened and tempered.
For polishing bone buttons with Trent sand.
For polishing lead shot with black-lead powder.
For cleaning the rust from cannon balls by their attrition against each other.
For drying small articles in saw dust after they have been annealed and pickled with acid, as in the blanks for coin.
For dissolving gums in spirits of wine as in making lackers and varnishes - and to which processes might be added numerous others.