How far apart should shelf pin holes be?

32mm — about 1 1/4" — is the system the whole cabinet industry is built on. Why that number, and how many holes a panel takes.

32mm system: holes every 1 1/4", which is what every piece of European cabinet hardware is drilled for.

A 30" panel with 3" left clear at each end takes 20 holes over 24" of usable height.

How that is worked out

  1. 32mm is not a woodworking figure, it is a machine one. Line-boring heads are built with spindles 32mm apart, so every hole in a factory cabinet — shelf pins, hinge plates, drawer slides — falls on that grid.
  2. In inches that is 1 1/4", which is why the spacing looks like an awkward number on a tape and is a perfectly round one in millimetres.
  3. Holes every 1 1/4" over 24" of usable panel gives 20 of them.

Holes per panel, both common spacings

Holes per panel, both common spacings
Panel heightHoles at 1 1/4" (32mm)Holes at 1"Usable height
24"151918"
30"202524"
36"243130"
48"344342"
60"435554"
72"536766"
84"627978"

Worth knowing

  • Use a jig, not a tape. Cumulative error is the enemy here: measuring each hole from the last one puts the two rows out of step by the top of the panel, and a shelf that rocks is the result.
  • Drill both panels of a cabinet from the same reference end, with the jig registered the same way. Which end you index from matters more than where the holes start.
  • Stopping 3" short at each end is convention, not a rule. There is no point in pin holes where a shelf would collide with the top or the bottom of the box.
  • 5mm is the usual hole for European hardware and 1/4" for North American pins. They are close but not the same, and a 1/4" pin in a 5mm hole is loose.