Madship Brewing

Build your own Motorised Malt Mill

Basic idea

When I started this project, I was after a motorised mill with ball-bearing rollers.  When I thought more about finding a suitable shaft for a ball bearing, and then getting a roller machined, and then adding a pulley, it came to me: all of these things come standard on a normal electric motor.  The ball-bearings and the shaft are there, and even the armature serves as a pretty good roller.

The design just got better after that.  I visited my local Domestic Appliance store, and found out that washing machine motors have a standard wiring that allows them to run at about 300 rpm: just about perfect for a malt mill.  By using the armatures of burnt-out washing machine motors, all of the mounting holes were similarly spaced, which made the design simple and effective.  My local dealer sold me the used working motor plus the two burnt-out motors for R280 (about $40).  Here is the completed mill:


I chose 50mm angle iron for mounting the three motors.  Mine was 5mm thick; choose a thinner gauge if you can find it.  The mounting is shown below:

Note that the aluminium mounting of the ball bearings needs to be cut away so that the rollers can be mounted close to each other.  One of the rollers is mounted on a slot in the angle iron (top left) so that the gap between the rollers can be adjusted.  There is a similar slot on the motor mounting for belt tension.

After this, weld on the legs, and the support for a bag of malt.  I bought a container of bubble bath because it had the right diameter throat to feed the grain to the rollers.  The basic angle iron frame must be supported in two dimensions; the leg braces do the job in one direction, and the malt bag braces do it in the other direction.  The latter braces also act as a useful support for the belt guard. 

I mounted the pulley of the free roller on the opposite side, so that it is easy to give it a spin to get the mill going.

It works like a charm; if you build one, let me know about it!

  • 2m 50mm x 3mm angle iron, cut into four 500mm lengths.
  • 2m 30mm x 3mm angle iron for leg and malt bag braces.
  • 3m 30mm x 70mm wood, cut into four equal pieces for the legs
  • 1.2m x 1.2m 9mm ply for holding a malt bag (my bag support is too short!)
  • A suitable plastic container to funnel the grain to the rollers.
  • 3 washing machine motors (one in working condition)
  • 1 V-belt
  • Paint

All these materials should cost you less than R700 ($100).

More information

For a more detailed description download this pdf file (199kb).