Sorry to take so long to respond. Thanks for the responses. I gave up on parts and invested in a new Jet 15″ planer with helical carbide cutter chips. I am very happy with it so far. Now I have a broken planer to dispose of – down to the port unless someone wants parts.
The “story” behind the mishap is a lesson in paying attention to our machines. I had been having trouble feeding lumber into the planer. It often required a fair amount of pressure or wiggling to get the board started. Rather than stopping to diagnose the problem, I kept going in order to get the project completed. The last time I pushed and heard an ominous clunck.
On taking the machine apart, I realized that the infeed roller adjustment had allowed the roller to sink unevenly and on the last push, I was able to essentially stop the infeed roller. The chain drive continued to pull on the outfeed roller against the weakest part of the frame casting, cracking it. The excessive twisting torque on the outfeed roller snapped the roller shaft and the chain snapped as it twisted up.
A lesson for all – pay attention to equipment that isn’t behaving normally and diagnose the problem before something more serious happens. Luckly for me, the planer parts that broke were housed behind a heavy steel cover and nothing went flying uncontrollably.