Vintage tire regrooving tool.
https://diqn32j8nouaz.cloudfront.net...tires_ma24.jpg
Previously:
https://www.homemadetools.net/forum/...952#post133775
https://www.homemadetools.net/forum/...675#post128712
https://www.homemadetools.net/forum/...628#post155502
https://www.homemadetools.net/forum/...532#post128084
https://www.homemadetools.net/forum/...739#post174836