i built that same mobile base using 4 swivel casters i had lying around. the use of 2 fixed casters will make the disengagement and engagement operations go much more smoothly allowing the tool to be positioned more precisely. if you have to use 4 swivel casters, try to get them all pointing their wheels in towards the center of the base. it makes activation a lot easier.
when they separate spontaneously, do they separate with the plywood leaves flipping up or down? i had this problem and remedied it by making the long plywood leaf longer than i thought necessary (this added leverage also makes engaging the base easier and provides more control in the lowering operation).
rather than using that storm door latch, i just created a pivoting brace that pushes the long leaf down and "locks" it in place (the garden gate latch i tried in the pic didn't work out).
just remember that the mobile base is designed to raise the base only a little to provide for mobility. my casters were 2", i think. smaller would have been better for the engagement of the leafs.
ps. jsut saw the above modified drawing. the longer the lower leaf is, the higher it will push the upper (longer) leaf up in the disengaged position. i found beveling the active edge of the lower leaf @ 45* to be very helpful in operating the base. and making the distance between the axles as long as possible will also help the operation of the base (that's one thing my base didn't do, but i was trying to jam the mobile base into an existing, rather crude wood frame tool stand).
Last edited by toolguy1000; 11-11-2011 at 02:21 PM.
there's a solution to every problem.......you just have to be willing to find it.