So I have a newer toro mower with a ruff blade (131-4547)and I think to ruff to re sharpen. I happen to have an older spare toro blade (108-9764) that I was going to replace with until I saw the number difference. They are both the same length, design is the same, weight appears to be similar. Can any one tell me if these are interchangeable or where I can look to make that determination. Curious if toro just changes numbers every so many years?
Thanks