Nice find, great to see one more saved.
Is it marked R&W or F&W? As Rob said,
Frost & Wood Company "was one of the largest manufacturers of farm implements in Canada. They were the largest munitions manufacturer in Eastern Ontario, producing hundreds of thousands of hand grenades and artillery shells."
R&W may refer to
R. and W. Hawthorn, Leslie and Company of St. Peter's, Newcastle-upon-Tyne (usually referred to as Hawthorn Leslie), a shipbuilding and locomotive manufacturer?