Glad to meet you! Yes, Jim Sandoe did have an artificial leg that was apparently due to a childhood accident. I would love to fill in the details of this family and if your interested can send you bits of info I have found on them, census reports, newspaper articles, etc.
I had found Jim and Mary on the 1930 census in Maryland, but couldn't be sure until you said her maiden name was Clap because her parents were living in their household, so that must be them.
Any birth dates, marriage dates, etc., you might be able to share would be great. You can email me at the address I gave to Corrina, or respond back here on genforum.