Tech Tip: Indexable Milling Lead Angle and Cutting Forces

We're talking lead angles today. When it comes to indexable milling, one of the main decisions is choosing a lead angle. It's key to remember that cutting forces are always perpendicular to the lead angle. In other words, whenever you change the lead angle, you're changing the direction of the cutting forces. For example, when using a 90-degree tool like a standard shoulder mill, the cutting forces are coming in directly perpendicular to the spindle. In long overhang applications, this could be more prone to chatter than a lead angle cutter. Kennametal has several options in lead angle cutters such as 45 degrees, 30 degrees, and high feed which typically has a 15-degree lead.