Covington 5" Bead Mill - Model 1039 - Make beads from 5/16in. to 3/4in. in diameter. Best suited for producing beads from hard material as Agate, Jasper and Jade. Preforming of Beads - It is necessary to cut the gemstone material into cubes, slightly larger that the desired size. Accuracy in cutting the cubes so they are uniform in size will hasten grinding. Complete the preforming process by grinding off all corners and sharp edges until the cube is a rough sphere. Milling - The preforms are placed in the cast aluminum 5in. diameter bead chamber with a 50/50 mixture of silicon carbide grit and water. The 4-1/2in. diameter x 1/2in. aluminum head has a 3/8in. recessed ring in the ceiling. Milling action is achieved by rotating the chamber with the location of the beads controlled by the milling head. Procedures - It is necessary for the operator to develop his own procedure by making test runs and keeping records of gemstones hardness, silicon carbide grit size and milling time. Remeber, softer materials require ligth mill head pressure and finer abrasive grit. Caution - The mill is not recommended for gemstone material softer that 5 on the Mohs hardness scale. Load - You can grind twenty 1/2in. beads at one milling. Cleaning - Chamber and head can be quickly removed for easy cleaning. Polishing - Beads must be polished in a gem tumbler Unit is a table model. The mill is mounted in heavy gauge metal housing. The head is belt drives by a 1/3 HP, 110 volt/60 Hz notor and turns at a preset RPM to produce uniform beads from preformed material. Bead mill comes assembles with instructions and guarantee. Overall size 18in. L x 11in. W x 12in. H. Shipping wt. 45 lbs. Shipping from California - call or email for shipping quote (Shipping calculated at checkout will not be accurate) Instruction Manual California state sales tax on all Drop Shipments within the state of California.