This invention relates generally to the field of food processing machines and more specifically to multi-purpose food grinding machines. Various devices both manual and electric have been designed and used to crush and grind items for use in the preparation of edible foods. For example, it is necessary to grind and crush the nubs of the cocoa plant in the process of making chocolate. One type of grinding machine uses grinding rollers that rotate on the flat surface of the inside of a rotating vessel causing the food items that are trapped between the grinding rollers and the flat surface to be crushed and ground.
However, there are deficiencies in the prior technology. First, the grinding rollers, which include a central aperture, are connected by a shaft, the aperture tends to become worn and loose over time. Second, the grinding rollers are not easily removable and replaceable so other types of grinding rollers cannot be quickly and easily installed. Third, there is no way to adjust the downward pressure of the central shaft that holds the grinding rollers in place, so the user cannot control how forcefully the grinding rollers engage with the base plate of the vessel. Fourth, the wiping blade that scraps access material off of the inside wall of the vessel, is not spring biased, so it can not automatically adjust itself for ideal scraping action. Fifth, the vessel is held only by the motor shaft and is not held evenly around its base perimeter. Sixth, there is no means for adjusting the temperature of the inside of the vessel. Seventh, there is no way to easily adapt the grinder to be used for other applications such as a mortar and pestle application.