next time you need to get a sprocket or somthing off that rusted on try this it works for me toilet bowl cleaner i had used it on a jack shaft the lock collar and sprocket was rustes so bad and used toilet bowl cleaner you could you see the rust melt off
i made one using a old gokart frame and cut the go kart axles off and welded them the bottom of the shopping cart it wasn't chrome plated it was like porcelain or some kind of baked on paint. pain in the *** to get that stuff off.