caster weight question....

[drumpriest]

I am working on the design for an under assembly table cabinet. I am thinking that it should be mobile, as everything in my shop is to this point, and I think it'd be useful.

I currently have a set of Rockler locking casters that are not purposed, but they have a limit of 110 lbs each, totaling 440 lbs. I am suspicious that it may not be enough. My assembly table is 3' x 4' made from top and bottom skins of 3/4" mdf and a grid internally of 1/2" mdf, with red oak trim. I suspect that it weighs 100lbs or so. Then figure in a project weight, which can vary, and the cabinet weight, as well as stuff in it. I guess I'm just looking for input from anyone with thoughts or who have done this sort of thing to see if I'm overestimating the weight needs here.

[annunaki]

Thinking Out of the Box

If it turns out that the weight might be excessive, why not add 2 or 4 more casters (they don't have to be locking, just the same size and swivel)?

[LCHIEN]

Overloaded casters and ven those approacing the limit may not fail completely but become hard to roll, hard to swivel and steer, most of which reduced you experience to an unsatisfactory thing. OTOHm casters that are well below their load limit roll well and steer easily, enhancing the users experience.

I would suggest being very conservative on loading.

Furthermore, with a stiff table and uneven floor, usually only two casters take most of the weight with just a little bit on the third and fourth casters. Finally with a load placed over once corner of the table, it may be that one wheel takes 75% of the total weight on the table.

If your table alone weighs 100#, and you expect to put loads of 200# on the table, I'd have at least 200# rated casters.

in general it has been explained to me that more casters are not necessarily good because of the load sharing is not necessarily even, and it makes it harder to steer and roll.

[Pappy]

I think you estimate on the weight is a bit light. The 3/4" skins are most of a sheet of MDF which weighs either 94 or 96 pounds.

This weighs in at 385# and I can steer it from either end. The casters are 4" wheels with steel axle bearings made by Darnell-Rose (casters.com) and have been in service over 5 years. I think I paid about $12 each for them.

[drumpriest]

Thanks guys, I'm inclined to agree that I should probably go overkill on this one. And Loring, I cannot imagine trying to have more than 4 casters, you are just asking for problems with teeter-totter motion, I would think.

I am having issues with the old casters under my SCMS, perhaps I'll put the 440 lb set under there and get something nice and heafty for under the assembly table.

thanks again,