Footrest . Adjustable . High Chair . IKEA ANTILOP

Robust and relatively simple, this footrest is impressively strong; by using the wooden dowel as a crossbar, the load is transferred to the clamps which connect to the legs. 

The wood dowel measures in at Ø.8495, so I think it's a 7/8" (.875") oak dowel; you can get it for like $5 at Home Depot.

#10-32 nuts fit snuggly into hex pockets, so you do not need to hold them with a wrench to tighten the clamp around the leg of the highchair:

Likewise, the crossbar clamp has been updated to use another #10-32 nut for screw to pull against (pushing blunt screw against wood), instead of using wood screws to penetrate into the wood. 

This change will make adjustments quicker and easier; and won't poke lots of holes in the wood; while still effectively preventing the crossbar from rotating and sliding:

#10-32 x ¾" long screws should be sufficient if you use hardwood; if you use pine or other softwood, the screw may compress the wood more and you may need to swap it out for a longer screw.

Please note, supports were not necessary when I printed these (the radiused bridging shown below didn't turn out very pretty but totally functional), however, you may wish to add supports if you don't feel confident your printer can handle it.

Feedback is welcome!

ENJOY!