I want to attach some wheels to a small table. It has a metal frame. The foot of the frame is just a square metal legs of 20mmx20mm with a little plastic cap on each of the 4 legs. Taking the cap off is hollow.

How would I attach something like this to each foot.

My initial thought would be to cut a small piece of MDF to size, maybe with 1mm larger and hammer it in? Then I would need to make some socket for the screw somehow? What is this even called?

Looking forward to ideas here, also would appreciate anyone help narrowing my terminology here so question is clearer. Thank you in advance.

enter image description here

  • 2
    Casters might work, but just keep in the back of your mind that the spindly legs might need reinforcement when getting wheeled around. (Brackets, cross-braces...) Commented Mar 10, 2023 at 3:05
  • 1
    always do an image search ... duckduckgo.com/…
    – jsotola
    Commented Mar 10, 2023 at 3:55
  • @jsotola good idea, so many good leads there like assetcloud.roccommerce.net/w700-h700-cpad/_outwater/1/6/1/… thanks Commented Mar 10, 2023 at 4:01
  • Agree with @AloysiusDefenestrate some stuff these days is made to minimum standards. Some chair legs might hold for a person sitting down, but add wheels and one wheel gets struck when moving and that leg will bend. Check the thickness of the legs.
    – crip659
    Commented Mar 10, 2023 at 12:59

4 Answers 4


You just buy the right casters.

What you need are "expanding stem mount" aka "expansion mount" casters, which are designed to insert into tubes, then be tightened to expand a rubber sleeve to grip the inside of the tube.

Expansion mount caster image from DHcasters.com - no affiliation or endorsement implied.

I mean, you could weld nuts in, but do you really want to bother with that?

Wood will very likely disappoint.

  • 1
    That's pretty cool. Just watched a Youtube video on these youtube.com/watch?v=BdD78Oj_GFk looks ideal for my use-case. Thank you. Commented Mar 10, 2023 at 2:36
  • Quite a lot of commercial products do weld nuts into square tube legs; I've even seen them present but conceal by rubber feet (or of course used to attach adjustable feet)
    – Chris H
    Commented Mar 10, 2023 at 10:49
  • @ChrisH Of course, it makes total sense for the manufacturer to weld in nuts. But as a DIY-project on a table that you want to have in your living room? If you're not a pro welder, it'll propably look bad even if you manage to get the nuts perfectly aligned.
    – arne
    Commented Mar 10, 2023 at 12:26
  • 1
    @arne welding isn't an option for me at all, but the weld should be hidden inside. Of course if the tubes are painted (or powder coated) that might not like nearby welding
    – Chris H
    Commented Mar 10, 2023 at 12:28
  • @ChrisH Of course you'd want the nuts inside the legs, but depending on the thickness of the metal of the legs, you'll get discoloration/scorched finish on the outside, that's why I said that welding isn't really an after-market option.
    – arne
    Commented Mar 10, 2023 at 12:52

"Footing" I suppose is the term? 30x30 mm and 20x20 I can find easily for sale.

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And your initail idea is not bad either, but MDF will break down soon. Hard wood or plastic would work well though.

Edit: those are called leg plug or end cap.

  • That sort of thing is great for axial loads, but not for any sort of tilt or shear- which is what you'll get with castors- since eventually you'll either dislodge the nut or relatively-small threaded insert from inside the plastic or flatten the fins holding the plug in place. Commented Mar 12, 2023 at 11:04

I did something like this by securing some long "joiner nuts" or "coupling nuts" up inside the leg.

enter image description here

Of course the internal thread had to match my casters stem.

Mine was a wooden leg but into the end-grain, so I drilled a hole to fit the outer corners and left the depth just right to support the weight. Then I epoxied the coupler-nut in the wood and reinforced the outside wiht industrial heatshrink. Its a garage/hobby table so looks don't matter.

In your case, welding a coupling nut in place might be a good solution, or if you have access to a workshop lathe then turn four inserts in steel, so they're a close fit inside the hollow leg. Leave a good lip to take the weight. Bore and thread up the middle to take your caster's stem.

To level the table, make sure each caster stem has a locknut under the insert that you can adjust with a spanner.

    stem of your caster
    \     |/|     /  <-- existing table leg
     \ +--|/|--+ /
    (_____|/|_____)    <-- visible bit, make it rounded over, shiny, and pretty.
      ====|/|====   <-- locknut, aka jam-nut/jamb nut
           Rest of your caster's wheel etc.

Ideally the insert should be a light hammer fit into the leg. If its loose, then some epoxy inside might be enough, or possibly welding will be needed. Depends what the metals are.


They are called caster wheels and come in many different mounting choices.

I would use a piece of real wood like a 1x1, but it will depend on the mounting choice you decide on.

  • Thank you. I do see other wheel designs for sale with a mounting plates (4 screw holes) but all variants look to exceed the 20mmx20mm of this table's legs (I don't have a flat base to screw in to). If I go with a piece real wood. Hammer in tight would be a sane approach? Any idea what tool and part I need to create the screw socket in the wood? Commented Mar 10, 2023 at 2:32
  • 2
    @MâttFrëëman Would not use the screw type, maybe the push-in pin/post type if you don't go with the expansion type.
    – crip659
    Commented Mar 10, 2023 at 2:41

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