Reinforcing/improving lightweight stands for mills?

[tuyere]

Howdy all,
The tables we use for our mills aren't up to snuff. They're lightweight stainless steel with poor bracing- these Uline worktables, for the record- https://www.uline.com/BL_803/Stainless-Steel-Worktables - so they wobble slightly if unbraced, and the tabletops are thin enough that they flex under the mills, allowing the machines to wobble when the spindle's movement resonates just right, even if the tables are immobilized.
The correct fix, as I am well aware, is to get beefier machine stands. Proper machine stands, not tables for general use. I have made a case for this several times. For various tedious reasons that fix is not in the cards, so I gotta improve these as much as I can.

So far, my strategy has been to use L-brackets and machine bolts+anchors to tie some of the tables into the concrete block walls, use clamps to tie the freestanding tables to the wall-attached tables, and then placed significantly-beefier welded worktables (

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) as 'bookends' at the end of a row of freestanding tables, doing the same immobilizing work as a wall-tied bench.
This has almost eliminated the worst of the whole-table swaying, but it's done little to address the less dramatic swaying you get from the flexing of the tabletop sheet. I can't reinforce the tabletops without an impractical degree of welded reinforcements and gussets, so my thinking is to just throw a thicker, stiffer 'tabletop' down over the existing one, either squares of cold-rolled steel plate, or using several cold-rolled flat bars under each set of mill feet.
Anybody ever attempted anything like this? Any recommendations (aside from "buy better mill stands")? I think 3/16" cold-rolled plate would be sufficient for a full-tabletop Enhancement, but that's not cheap for 5 tabletops and 7 mills. I'm also thinking of 1/4"-thick cold-rolled flat bar, two long bars at least 4" wide and running across multiple tabletops, with every mill's rear and front feet sitting on a given bar. That would be cheaper and would help tie all the tables together and machines together into a single mass that one mill's oscillations won't impact, but it won't distribute the weight as evenly across the tables themselves.

 

[tuyere]

Here's my extremely professional mock-up for what I'm thinking with the flat-bar reinforcement approach:

A sample layout, the table at far right is tied to the wall but the three horizontal ones next to it are free-floating. Yellow blocks are the mills, two per table.



Here's how I'd use the flat-bars- use the longest possible runs to bridge multiple machines and tables, with all pairs of bars bridging at least an entire tabletop (so the reinforcements themselves won't wobble on top of the tabletop, which might happen with two short bars under a single mill).
To damp vibrations and help make up for slight differences in tabletop heights, I'd face the undersides of the flat bars with adhesive-backed rubber or cork sheet.

Any glaring problems with this approach?

 

[CoolHandLuke]

1. level the tables
2. brace the legs
3. if you secure the tops together, also secure the legs
4. little rubber feet
5. if you can sit on the table and have an epileptic fit and the table doesn't move, you're ok. stand on it and dance. if you don't feel comfortable on it, your mill won't either.

 

[tuyere]

1. level the tables
2. brace the legs
3. if you secure the tops together, also secure the legs
4. little rubber feet
5. if you can sit on the table and have an epileptic fit and the table doesn't move, you're ok. stand on it and dance. if you don't feel comfortable on it, your mill won't either.

I've got the actual table movement more or less handled, they're basically all lashed together and bolted to the wall at multiple points. The problem is the tabletops aren't rigid and can flex independently of the rest of the table. The body of the table is immobilized, the legs are immobilized, but the tabletop can still move enough within that to cause a fair bit of mill movement. It's just 16ga stainless sheet supported by a couple of internal channels, also made from sheet metal fabrications; you can see it puckering downwards under each rubber mill foot, and there's enough flex and springiness for the mills to sway back and forth when the spindle makes lots of fast back-and-forth movements.

 

[zero_zero]

I got a local carpenter to make solid hardwood bench for my mill out of macuil, 5cm thick benchtop, plenty of bracings, 12cm square legs... it could support an elephant, and it took four guys to move it. Money well spent IMO

 

[tuyere]

I got a local carpenter to make solid hardwood bench for my mill out of macuil, 5cm thick benchtop, plenty of bracings, 12cm square legs... it could support an elephant, and it took four guys to move it. Money well spent IMO

I suggested we do something like this, or just use some of the very sturdy wooden packing tables we have available, but a basic requirement from the higher-ups is that the stands/tables are stainless steel, and that they all match. Again, not what I would prioritize, but that's the hand I've been dealt, it's not something they're gonna flex on.
In any case, I used to work with welders and I got a ballpark quote for making us machine bases, or even rigidizing our existing tables with some ribs n gussets, and the price makes it a nonstarter.

 

[JKraver]

I've got the actual table movement more or less handled, they're basically all lashed together and bolted to the wall at multiple points. The problem is the tabletops aren't rigid and can flex independently of the rest of the table. The body of the table is immobilized, the legs are immobilized, but the tabletop can still move enough within that to cause a fair bit of mill movement. It's just 16ga stainless sheet supported by a couple of internal channels, also made from sheet metal fabrications; you can see it puckering downwards under each rubber mill foot, and there's enough flex and springiness for the mills to sway back and forth when the spindle makes lots of fast back-and-forth movements.

Buy a sheet granite or a thick piece of ply if you are cheaper. Anchor ply in several places with flush bolts.