This is a jig for drilling extra holes in wooden shelving systems that uses pegs to locate the shelves. I used it for some old Ikea Billy shelves that use 5 mm pegs. Ikea kitchen shelving may also work with the tool as is, but the tool can also easily be customized for other systems.
Printing is straight forward. I used PLA which has minimum shrinkage issues.
You can use a piece of tape around the drill bit to indicate correct depth. A tip for Billy is to use a 4.9 mm drill instead of 5.0 mm - this gives a nice fit for the pegs.