Pre-shaped threading lathe bits ready to use. The 55 Degree cutters are designed to cut the true threads of the 98 Mauser. The 60 Degree cutters duplicate most after market Mauser barrel thread patterns. Notes: Square bit cuts a true 12 threads per inch square thread for 03 Springfields and Enfields Level action cutter cuts the 12 threads per inch found on Marlin lever guns and Remington Rolling Blocks