After looking at David Best's pictures, I actually looked up the specs on the Felder machines.? The Felder 51/510 sized machines actually have a 140mm port (5.5"), so I would think you can clamp down a 6" hose onto this.? The smaller 410 and under machines all use 120mm ports (4.72").
Andy - the restriction/loss of 5 foot of hose is equivalent to about 20 feet of smooth duct (i.e. spiral or Nordfab).? I want to try to remove as much of this hose restriction as possible.? This is really important on edge sanders, but I have read posts from people who are using 6" hose on their 41 size jointer/planers with a lot of success.
