Starrett Machinist's Blue Dye - 4 oz.

Layout dye for when you're fitting tool parts precisely, making your own hardware, or working on castings or formed metal, this opaque, fast-drying dye will give you the reference surface you need. Find out exactly where parts make contact (and where they don't), or provide a high-contrast background for clean, lightly scribed layout marks. Washes off with alcohol or lacquer thinner.