Lock For IKEA Billy Doors

This little thing keeps my 2yr out of my Billy bookshelf with doors. I have constructed it for my doors, so please be sure you have 6mm clearance between the doors.

You Need:

1 x M3 washer of any kind, bigger is better
1 x M3 screw or small wood screw. If you want to use M3 screw drill the hole to 2,5mm.
1 x Spring 8x15(aprox). Inner diameter of 6mm is important.
1 x Small Wood Screw for fastening to shelf
I cut a bigger spring to size, just make sure it is strong enough to pull the k