A fastening tool can include a housing and a motor assembly in the housing. The motor assembly can include an output member and a motor for translating the output member. A knob can be rotatably mounted in the housing around a first axis and define a plurality of locating formations arranged thereon. An adjustment rod can be operatively coupled for movement with the knob. A lower contact trip can be coupled to the adjustment rod. An indexing member can be movable along a second axis parallel to the first axis. The indexing member can be selectively biased into engagement with one of the locating formations upon rotation of the knob to resist rotation of the knob relative to the housing. Rotation of the knob can cause the contact trip to translate toward and away from the housing to define a desired penetration depth for the fastener.