Craftsman Tiller Shoulder Screw 938-0688 0.75 x 3.00 x 3.00 Genuine OEM Replacement Fits Craftsman MTD. This is a Genuine OEM Craftsman part. This screw (part number 938-0688) is for tillers. Follow appropriate safety practices when installing screw 938-0688. Also fits these brands: Craftsman, MTD... - Craftsman Tiller Shoulder Screw 938-0688 0.75 x 3.00 x 3.00 Genuine OEM Replacement Fits Craftsman MTD.