Not knowing what a 31-15 looks like, I googled it and learned it is a high shank machine. Sewingpartsonline.com has a high shank walking foot for $79.95 plus S&H. The number is XA7253001. Amazon.com has the same foot for about $10 less. You might find one at a better price somewhere else. They are often referred to as a plaid matcher.
It looks like there are more walking feet for super high shank machines than for high shank ones. The only high and super high shank machines I am familiar with are old Kenmores.
Last edited by elnan; 02-04-2016 at 07:43 AM.