I made this because all of the ironing board mounting hooks I found on Thingiverse were either too small (the hook for the bar), or did not firmly hold the ironing board bar.

The bar socket for this is 23mm, but my ironing board bar is 22.5mm, and it clips in nice and snugly. Also the holes for the screws are 5mm.

I printed it with 100% fill to add strength, on it's side with support everywhere. 20% fill would have been about 16 grams, where 100% was 32 grams (for a set of 2). I figured the extra $0.30 (or so) was worth the additional strength.