I keep forgetting to post here...I'll have too put a big sign on my bench or something....anyway.
Recently finished a Ruger SR1911. The grip screws were my favorite part...
I first cut my borders without the smoothing the sides. The shot peened finish is unbearably hard and crumbly. I finally smoothed the sides to 600 grit on a granite block and it cut just beautifully - smooth and sparkly. I wouldn't hesitate to cut another as long as I remove the shot peened finish first.