Recommended for cutting thin cross-sections such as tubing, small bars and light angle iron. Because blades are relatively thin they should be used only on light machines. Power Saw Hacksaw Blade Tooth Recommendations: TPI: 18. Suitable for Section Width: up to 13mm (up to 1/2”). TPI: 14. Suitable for Section Width: 6 to 19mm (1/4” to 3/4”). TPI: 10. Suitable for Section Width: 8 to 25mm (5/16” to 1). TPI: 6. Suitable for Section Width: 13 to 38mm (1/2” to 1 1/2”). TPI: 4. Suitable for Section Width: 19mm and above (3/4” and above).