Kitchen Chair Footrest
A dining chair is built around an adult’s legs. Sit a four-year-old in one and their feet hang in mid-air for the whole meal, which is why they end up kneeling on the seat or hooking a toe under the rail. This is the fix: a bracket that slides up a chair leg, clamps wherever you want it with one bolt, and gives them a 200 mm platform to put their feet on.
It is one bracket per leg. Print two, put one on each front leg and set them to the same height — each platform is 200 mm across, which on a dining chair is most of the way to the middle. Slacken one bolt and drop them as the child grows, and the chair goes back to being a chair when they don’t need them any more.
The socket is a 25.4 mm square and nothing else fits it. That is a 1 inch square leg, straight-sided at the height you want the footrest. Measure your chair before you print 300 g of plastic. A round leg, a tapered leg, a 22 mm leg and a 30 mm leg are all a no — see below for what to do about it.
The shape
Every number here is measured off kitchen_chair_footrest_v6.step in this
folder.
| Feature | Dimension |
|---|---|
| Overall | 201 × 182 × 53 mm |
| Platform | 200 × 180 mm, 8 mm thick |
| Platform corners | Three on a 50 mm radius; the fourth cut off at 45° beside the leg |
| Leg socket | 25.4 mm square, straight through all 53 mm |
| Socket bearing band | The top 20 mm, next to the platform |
| Socket below the band | Opens out to about 34 × 32 mm |
| Wall between socket and cut corner | 6.8 mm — the thinnest section on the part |
| Clamp boss | 33 mm diameter, under the platform |
| Clamp hole | 5.9 mm, axis 16.5 mm above the bottom face |
| Nut pocket | 9.8 mm across flats × 5 mm, open at the bottom face |
| Model volume | ~550 cm³ |
Two rows in that table are the whole design, and they are worth spelling out.
The socket only touches the leg in two places. It is a true 25.4 mm square for the top 20 mm, then steps out to roughly 34 mm for the rest of its depth. The other contact is the clamp bolt, 16.5 mm up from the bottom. A load on the platform is therefore reacted by the leg pushing on the top band one way and the bolt pushing the other way 30 mm lower down — a proper couple, rather than a long sloppy sleeve that rocks.
The bolt points inward, under the platform. Its axis runs from the boss through the centre of the socket and on toward the far corner of the part, so the head sits beneath the footrest where nobody kicks it and you tighten it by reaching under. It also means the clamp load lands on the socket wall backed by that 6.8 mm corner, which is why the print settings below are what they are.
Parts
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- M6 × 40 mm hex socket cap screw — one per bracket. It needs roughly 33 mm under the head to cross the boss and reach the leg; 40 mm gives you travel, and 45 mm is fine too
- M6 hex nut, 10 mm across flats — a plain 5 mm nut, not a nyloc. The pocket is 5 mm deep and press-fit at 9.8 mm across, so the nut is captive and you never have to hold it with a spanner
- SUNLU PLA+, 4 × 1 kg — the default. About 300 g a bracket at the settings below, so two of them is most of a spool and the multipack is the one to buy
- eSUN PETG, 1 kg — the alternative if the chair lives in a conservatory or anywhere that gets real afternoon sun. PLA is the stiffer of the two, which is what you feel in a cantilevered platform, but it starts going soft somewhere around 55–60 °C
- Digital caliper, 0–8 in — you are fitting a fixed square hole to somebody else’s furniture, so measure the leg first, at the height the bracket is going to sit
- DEWALT twist drill set — the clamp hole is drawn at 5.9 mm and an M6 bolt is 6.0 mm, so it wants a 6 mm bit run through by hand
- Deburring tool and a needle file set — for the mouth of the socket and the walls of the nut pocket
- Bambu Lab A1 — the platform is 201 × 182 mm, so this needs a 220 mm bed as an absolute minimum. An Ender 3 takes it with about 9 mm to spare each side; a 180 mm machine does not take it at all
Optional, and both worth it:
- Anti-slip tape, 4 in × 30 ft — a strip across each platform. Printed PLA under a sock is slick. It is 80 grit aluminium oxide, so it is meant for shoes and socks rather than bare feet
- Clear self-adhesive rubber bumpers, 200 pcs — stick one on the leg where the bolt tip lands. A steel bolt tightened straight onto a finished chair leg leaves a dent, and it will still be there when the child has outgrown the footrest
Print settings
| Setting | Value |
|---|---|
| Layer height | 0.2 mm |
| Walls / perimeters | 5 |
| Infill | 30% |
| Supports | None |
| Material | PLA+ indoors, PETG anywhere hot |
| Orientation | Platform face down on the bed, collar pointing up |
Flip it in the slicer so the flat top of the platform is on the bed. As exported, the collar and the gusset hang below the platform; turned over, the whole part becomes a spire that gets narrower as it climbs, and there is not one overhang in it. The gusset tapers inward, the square socket is a vertical hole, the nut pocket opens upward at the very top, and the only thing that needs a bridge is the 5.9 mm clamp hole, which spans itself.
It also puts the layers the right way round. The platform’s layers stack through its 8 mm thickness and every extrusion runs the length of the plate, so a foot on the end of the cantilever pulls along the lines instead of trying to peel them apart. And the smooth first-layer face ends up on top, which is the surface feet actually touch.
Five walls, not four. Two of them are doing structural work you can point at: the 6.8 mm wall between the socket and the cut corner takes the entire clamp load, and on a 0.4 mm nozzle five perimeters is 4 mm of solid shell in a 6.8 mm section. The 30% infill is there for the platform, not for the collar.
Fitting it
-
Measure the leg at the height you want the platform, on both faces, with the caliper. If it reads 25.4 mm square and straight, carry on. Chair legs are very often tapered — a leg that measures 25.4 mm at seat height can be 22 mm at the floor — and it is the widest point below your mounting height that decides whether the bracket will pass at all.
-
Dress the socket. Run the deburring tool round both ends of the square hole. The first layer is where the squish lives, and the socket is drawn at nominal with no clearance in it, so a bracket that will not start is nearly always a lip on the bed face rather than a hole that is genuinely too small.
-
Ream the clamp hole with a 6 mm bit, turned by hand. It is modelled at 5.9 mm on purpose so the bolt runs true rather than rattling, but a printed hole always finishes under size and an M6 will not push through as printed. Don’t put the bit in a drill on a trigger; it grabs and winds the plastic out.
-
Press the nut into its pocket in the bottom face. It is 9.8 mm across for a 10 mm nut, so it goes in under thumb pressure and stays put. If it fights you, two strokes of a flat needle file on each wall of the pocket — those two walls are the only thing stopping it spinning when you tighten the bolt.
-
Slide the bracket up the leg from the foot and hold it where you want it. Which way the platform points is not yours to choose: the socket’s square runs at 45° to the platform’s edges, so the flats on the leg decide the angle. Dry-fit both brackets before you commit to a height, and see where the platforms actually land.
-
Run the bolt in and nip it up. Hand-tight on a short hex key is the whole spec — you are pushing a steel bolt against a 6.8 mm plastic wall, and torque past the point where the bracket stops moving buys you nothing but a split corner.
-
Set the second one to match. Measure up from the floor, not down from the seat. Chairs are rarely as symmetrical as they look.
If your leg isn’t 1 inch
Don’t scale the part. Scaling it to suit a 28 mm leg takes the platform to 221 mm, which is off the bed on a lot of printers, and takes the nut pocket to 10.8 mm — at which point the nut spins in it and there is no clamp at all.
Open kitchen_chair_footrest_v6.f3d and change the square in the socket sketch
instead. The STEP is there too if you would rather work in something other than
Fusion.
A round leg is not a resize job. A square hole on a round leg touches it in four lines and pivots on them, so that wants a different sketch rather than a different number.
Two things that will bite you
The 45° corner is the weak point, and the clamp aims straight at it. There is 6.8 mm of plastic between the socket wall and the outside of the platform’s cut corner, and the bolt’s job is to push the leg into exactly that wall. It is plenty for hand-tight on a well-printed bracket with five perimeters. It is not plenty for a socket wrench, and it is not plenty for three walls and 15% infill.
It is a footrest, not a step. The platform is 8 mm of plastic on a cantilever, and the gusset under it stops well short of the outer corners — past that it is an unsupported plate. A child’s feet, all day. An adult standing on the far corner to reach a cupboard, no.
Files & downloads
Printable parts
CAD source
The design itself, if you want to change it rather than print it. A STEP file is exact geometry and opens in almost anything; a Fusion 360 archive keeps the modelling history, so you can go back and edit the sketch that made the part.
- kitchen_chair_footrest_v6.f3d Fusion 360 archive — the editable design, with its history
- kitchen_chair_footrest_v6.step STEP — opens in Fusion 360, FreeCAD, Onshape, SolidWorks