I'd like to know opinions about filter maintenance. (Oneida would have an answer, but might be biased towards sales?): On a 3hp Oneida cyclone, the pressure (between the cyclone and filter column) is 0.5 cm H20 when running with the filter is at its cleanest. By the time the chips collection drum is full, the pressure is 1.5 to 2 cm H20. (Manufacturer says not to allow 5 or more).

Their method of cleaning the filter has no apparent effect on the pressure measurement: blowing air at the outside of the filter (when not running). In fairness, I haven't let the system get close to that 5 cm limit, but I assume that would happen eventually. Since I don't even see a little improvement with external compressed air, I've taken to removing the cylinder and its trap, setting it (vertically) on the floor with a flexible shop vac tube suspended inside. Then I blow compressed air tangentially at the INSIDE of the cylinder. Dust is grabbed by the vacuum, (so it doesn't rise into the shop) or it falls to the floor. I ask because some people claim that the filters can be harmed without visible damage.

Is what I'm doing a bad idea, perhaps increasing the levels of the smallest dust? If it is, maybe letting the pressures rise would be wiser (up to 5), but if I get there, is the safe next step to let Oneida sell me another filter?