Hello all.

Is there a generally accepted "Foolish to go past" limit on the length of your Z axis?
I'd originally planned to build my 8020 machine with 6-7 inches of Z travel, now I'm starting to worry that may be too much to stay rigid. Perhaps its more reasonable to just go 3-5 inches instead. I'd like to be able to cut out a storm trooper helmet in one piece, but I'll mainly be cutting much thinner wood, aluminum, and hopefully brass...so perhaps the shorter travel will be wisest. The Gantry is 36" 6030 w 1/8" CRS bolted on back, the risers will be either 1 or 2 pieces of 3030 stacked, laying down and bracketed with more aluminum. I'll be using a 2.2kw Chinese spindle on THK rails.

Any experiences, tips, hints or conjecture will be fully appreciated.