At first, we tried using a vice to flatten the pipe ends.

We used a 2x4 to keep the the first flattened end parallel with the other end.

Steve works with the vice. This worked "ok" to get the crimp started, but we ended up stripping the theads on the vice.

Tried another vice.

Then we realized that using a sledge hammer was more effective.

More flattening by Chris and Joe.

This is an example of a flattened end on the seam of the pipe. There's debate about how much of a problem this actually is, but we tried to avoid it.

Here's a good example of a flattened end.