Sansoo....Where did you get your wheels on the bottom?  I put wheels on my Dewalt planer cart I made up and I put wheels on it like your filter system, but the little tabs to lock the wheels on mine are much smaller and I have to fiddle with them to get them to unlock.  Yours look so much easier to deal with because the lock / unlock tabs are much larger.  I like that they lock both the rotation of the wheels but also the swivel but mine are a pain to unlock.

    ----  Yolanda

Yolanda