49.753 = 3" Jeweler's Adjustable Saw Frame with Tension Nut

They have strong steel frames with full size wood handles. A large thumb screw makes opening and closing blade holders easy. The top has a tension spring to hold frame in a fixed position. The handles are hardwood. The saw frames with tension screw features a thumbscrew at the front of the frame. Twisting it adjusts the tension on the sawblade.