Most of what I build is like the story of Stone Soup, totally happenstance and predicated on what shows up in time to be thrown in the pot.
I was doing my usual trolling and was trying to find a reasonable deal on 5"x2" casters but this kept weighing in at between $50 and $100, which to be fair would have cost several hundred if purchased retail at Grainger. Then some Tente brand 8" hospital bed casters with total lock and plenty of capacity showed up on Ebay for a penny plus flat rate postage. I put up a buck and being the only bidder got them for a penny.
These things are like jewelery compared to what I was seeing at Northern Tools and even Wood Craft. But they are tall, which for rolling a saw cabinet/router table that is 60"x42" out and about the garage and driveway is a good thing. When they lock there is zero play or jiggle. The mechanism is very clever, all internal and operated by twisting a hex rod that goes through the stem so one rod can lock 2 wheels easily, and for the more mechanically inclined, lock all four wheels with one lever.
But I don't know how to consider the issue of stability and the distance from the ground to the bottom of the cabinet.
At times in my mental experiments I am convinced it makes no difference and depends wholly on the stability of the caster and other times I am unsure if placement of the caster is a variable.It would be simple to mount them right into the 3"x3" uprights of the bench which would take the bottom about 9.5" off the ground.It would also be simple to extend the stretchers beyond the uprights about 6.5" and create a spiffy cut out mount to allow full wheel swivel and drop the bottom of the cabinet much closer to the ground. It would look like some sort of palanquin with the wheels as servants to the King cab. This sort of out rigging of the wheels on the short sides of the bench would not be in the way because the long front is the business side of this craft. But it adds a foot to a bench that is already pushing the envelope of what should be considered movable. It will need to be moved and parked along a wall when it is not used.
To the engineering experts with and without degrees, does the lowered center of gravity make the cabinet which will, regardless of what is going on below the top, always be about 36" from the ground, any less stable than a cabinet with a 36" height that started life closer to the ground? I guess we will zero out the difference between the stability of tall v. low casters for argument sake because the same tall casters are used in both scenarios.
Clearly a 2"x2"all steel caster is going to be more stable than an 8"x1.5" hospital bed caster of equal quality. But these are remarkable casters with zero jiggle and my other choices are ok quality 3" casters I have but what ain't such a smooth ride. Loosing ten inches of storage underneath is not an issue if there is no difference in stability. But if putting the wheels on out riggers to drop the bottom closer to the ground, increasing storage and weight in the bottom of the vessel made this monster more stable then it would certainly "look" more stable even if the height of the bottom relative to the ground was a distinction that made no difference.
I look forward to some design advise so long as the need to make this highly and easily portable is privileged. I played with a low down tow bar design like Rob built for his equipment and that is clearly the most stable of options. But I have to travel every time I use this behemoth and do some double parking to get around things and push it against the wall.I did not find the tow bar design as maneuverable as the bases I have with four swivel casters.
Such are the trade offs in a life.
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Originally Posted by Mike Nolan
