As Kenny has suggested re a lathe purchase , give the same amount of thought to a stabilization setup . It is easy to get sucked in to wanting to do larger items once you`ve become familiar with it`s possibilities . If you are certain that 6 inch length will be max , I suggest 10 inch height . Unless , of course you might some time feel the desire to stack 2 layers of 6 inch blanks in the chamber , at which point 16 or 18 inch would be better . The reason for that amount of freeboard above the blanks is twofold . The least important is having enough resin covering the blanks when vacuum is released to prevent air entering the wood pores - that is easily solved by watching the process for a few minutes after vacuum release , and adding more juice if the level appears likely to go below the top of the wood . The main reason for the freeboard is to reduce the possibility of sucking juice bubbles into the pump as the vacum is being applied . The pump is the most expensive part of the system . Vacuum needs to be ramped up slowly , watching the bubble level , to make sure none of the juice enters the pump .