Cracked Bridgeport Right angle milling attachment

I just purchased a used right angle attachment from a local tool dealer for my Bridgeport. He had quite a few Bridgeport brand that had cracked housings where the quill clamp slit ends. I guess this is a weak point. The H & R unit I ended up buying had a thicker cast iron housing than the Bridgeport brand unit so maybe it's a little stronger. What is it people are doing, or forgetting to do that winds up breaking them? I intend to only use it with R8 collets and end mills, not with the horizontal milling arbor.