I am in Canada and have two 5946's a 5906 and a 5904. One of the 5946's has a cracked frame in the same spot, and a friend has a 5906 (that I sold him years ago) with the same problem. The earliest 5946 did not have a heat treated frame, so it will crack. Smith is aware of the problem, and I would think the 5906 was a first gen and probably was not heat treated as well. Later versions are heat treated and do not have this problem. I am getting my 5946 tig welded and back in service soon, as Smith won't replace the frame except for original owners.