I'm having trouble drilling into dominoes - the edges keep cracking off. What am I doing wrong?
I'm going to assume these aren't the old black wooden dominoes but rather the plastic ones. You are probably getting too close to the edge. I would recommend using a glass/tile drill bit and using a drill press if you have one available. This will give you more control and a more precise placement of the drill bit. To find the closest you can get to the edge without cracking the edges, take one of the already cracked dominoes and drill some holes on the sides. When you find the proper spot take measurements. After you do a few with the 'safe' measurement you'll be able to eyeball where to drill.
Hope this helps,