These are the top quality scroll saw blades woodworkers ask for by name - OLSON! Use these blades with scroll or jig saws manufactured or sold by Delta, Rockwell, Powermatic, RB Industries, Hegner, Sakura, Shopsmith, Excalibur, Rexon, Sears, as well as hand-held fret and jewelers saw frames. These 5" blades will easily handle precise cutting of irregular shapes and straight cut off applications in all types of sheet materials. Mach Speed Scroll Saw Blades are engineered and designed after the PGT Precision Ground Tooth blades! Mach Speed blades offer the same wide spaced, ultra sharp teeth for fast, accurate cuts in hard and soft woods. The difference? Mach blades are precision milled. Widely spaced gullets that minimize burning and provide rapid chip removal. Reverse teeth cut on the upstroke and eliminate underside tearout. Position blade with reverse teeth in bottom blade holder. 2-5 teeth should appear above the table surface to score the work piece on the upstroke. Adjust feed pressure to prevent burning. This blade is.046" wide x.017" thick. TPI is 8/6 Skip. The universal number for this blade is 7R.