- Features such as ribs and bosses must not be placed in the way of lifter motion. Depending upon the size of your lifted feature you must allow for three things, the lifter body, lifter stroke, and 0.050" wiggle room to the next feature. These three requirements really depend upon many factors including the overall size of your part, the depth of undercut to be pulled, shape of the feature that you are pulling and the style of lifter used. As a rule of thumb however, if you are just pulling a typical hook or snap, leave 1.250" of room for lifter body, stroke, and clearance.