Thread: Antique market finds: 8/8 WB, Engels, Tuckmar

You have my commiseration; been there and done that, and felt the pain!
In the future, it is very helpful when using a Dremel to open the blade fully at a 90 degree angle with the scales, and place it on a soft fabric or rubber mat for polishing. The trick to prevent catching the blade edge is to hold the tang and keep a constant downward rotation of the edge into the material below. I never use the edge of the felt pads on the blade itself, only the flat side. It has worked for me, at least, and I have cracked no more blades.