Technically, Don, dropping the plane off your bench to loosen it wasn’t “my idea.” It’s just what seems to happen occasionally when working with the things – sort of a tongue in cheek response. That said, I’m glad it worked for you!
Regarding your other question, I think it would be best if you were to replace the faux iron with an actual plane iron. There are a few reasons for this:
1. It’s impossible to know exactly what kind of steel that old file is made of;
2. It’s impossible to know if whoever made it into a plane iron brought it’s hardness down via anealing;
3. It’s impossible to know if anything was ever done to it at all other than cosmetic changes to make it look like a plane blade.
4. A file isn’t a plane iron.
It would be a cinch to purchase some tools steel and make a O1 replacement blade or to contact a vintage tool dealer and try to find a suitable replacement iron.
To make a plane iron, I suggest you get a copy of the book “Making Wood Tools” by John Wilson. His website is http://shakerovalbox.com. You can get this book at a lot of different places but I like to deal with the actual creator whenever I can – they make a little more money that way and it’s a good way to forge relationships with fellow woodworkers rather than corporate America. John’s old school good people. He sends you the book without pre-payment. It’s unheard of in today’s trustless world. It’s like a breath of fresh air. I’ve enjoyed my opportunity to chat with him and learn from him and I’m sure you will, too. His book will tell you everything you need to know about making a plane blade.
If you want to buy one, you can probably find a suitable replacement iron in an antique shop, but if you want the shortcut to a fast fix, contact Ed Lebetkin at The Woodwright’s School. Ed has the tool store upstairs from Roy Underhill’s school. I don’t get the opportunity to go there till this fall, but I’ve heard wonderful things about his store.
Hope this helps!