SWITCHBLADE? 3 Blade Replacement 1-3/8″ Kit. Get the replacement blade that makes your Milwaukee? 1-3/8″ SWITCHBLADE? Selfeed Bit instantly new. Milwaukee SWITCHBLADE? Replacement Blades are made of hardened steel for long life. They’re easy to change out, so you?re always ready for faster drilling and less downtime on the job. The 1-3/8″ SWITCHBLADE? Replacement Blade Kit includes 3 replacement blades, 2 set screws, a hex key and storage case.