Ever have a bore that's a little tight, one that could use some polish, or need something for shaping a port?
This is your tool.
Take a piece of 1/4" drill rod, or quality 1/4" bolt, and cut a slot in it with a zip-cut disc.
If you need to open a bore .0005" or more, or polish it, use your die grinder, and some 400+ grit emery, and go at it, but be careful, material comes off way faster than you'd think. Great for polishing a throttle body with 220, or you can rough out a port with a carbide cuter, then finish with this tool. With 50-60 grit, you can shape and smooth a port in a matter of minutes.
