Last time I changed knives on the Dewalt 735 I found a pile of dust building up under the blower port. I took the blower housing outer half off and looked for damage or cracks but couldnt see any problem. Cleaned up the dust and reassembled it all. About a week later I was planing and noticed a little trickle of dust from underneath the blower port. Took the top off again and more dust had built up inside. I finally disassembled the whole chip blower and still could not see any problem. It was there but difficult to see. Look at the photo below at the end of the pencil you can see a little white spot. That is from a flashlight shining out from inside the housing. A hole that small can pass a lot of dust if there is a force behind it. Ordered a new housing (whick looks better-made with a tongue and groove closure between the blower housing halves). Problem solved.