I have a few clamps of this type in my home workshop that are used in various jigs. I recently bought two of these for homemade coping sleds. While fulfilling their intended function, they are definitely inferior to others in my inventory. Disadvantages: 1) The locking mechanism is activated before the swivel arm reaches the horizontal position (for horizontal fixation of the base), so the threaded rod is not perpendicular to the clamped workpiece; and 2) the threaded rod is too short to reach the workpiece flush with the base even in the maximum extended position. This disadvantage requires the use of a spacer in many applications.