The actual depth of cut on this hole saw is approximately 1 3/8 inches, the measured internal depth is only 1 1/2 [photo] - but it does not include the spindle threads [photo] So you have an actual depth of cut of about 1 3/8. This isn't useful if you don't have access to both sides or are cutting multiple pieces. Other similar sized bits I have account for the threaded mandrel and cut the full 1 1/2 the depth.