The only problem I foresee is that two of the casters’ locking levers are going to be difficult to access after you move the cart. Of course, that’s usually the case with the usual casters-underneath configuration. I usually end up locking just two casters on my drill press cart.
Ron - I hadn't even considered the failing caster scenario, but that's a good point. For me, the main benefit is that it helps to maximize lateral stability (because I can make the back piece taller), which I thought would be prudent with such heavy tools. It also increases storage depth, although now it's chopped-up.
I bought 4 locking casters, but I'll probably only use the ones that are easily accessible. I locked 2 and the cart wasn't going anywhere.
