My dad bought some Crankbaits at a yard sale and I was wondering how to tell how deep they dive? This is a crazy mixed bag of cranks, just wondering how I would know what depth they'll dive so I know I can get bottom contact etc

On the most basic level - It's all about the lip; the longer the lip - the deeper it dives but not always.

 

Line size and casting distance will effect the running depth as well.

 

Best way  to know is to take them out for a test drive -

 

A-Jay

After you have found out the depths by hitting bottom over a known depth mark them so you remember how deep they run.

While you can't tell the actual depth, all other things being equal, a bill that's straight, i.e., parallel to the body, will run the deepest. The more the bill angles downward the shallower it will run.

The overall length and angle of the lip is a general guideline to help determine the approximate diving angle and depth, but the placement of the line tie and the width of the lip also come into play.  Like A-Jay said, take 'em out and check them. I break my baits down into three catagories for storage purposes (shallow, medium and deep), but I also mark the lips with the exact running depth if I know it.