Abstract: Apparatus for tapping or threading holes in material reduces stresses and the danger of breakage of the tap by rotatably driving the tap at locations on the tap that change as the tap enters the workpiece. The driving element engages the tap at a point close to the surface of the workpiece. As the tap advances into the workpiece, the driving element remains close to the workpiece surface, engaging the tap at sites progressively advancing toward the end of the tap. Special taps are provided, one of which is double ended. This may be turned end for end to double the useful cutting life. This embodiment is driven by its flutes. Another tap is driven by a non-circular shaft extending from the threaded portion of the tap. The taps may be removed from the workpiece by passing through the threaded hole, thereby eliminating the need to unscrew the tap through the already tapped hole.

Abstract: A quick release device for use with a helmet having a face mask comprising at least two generally U-shaped clips having an outer leg, an opposite inner leg and a transverse slot disposed between the outer and inner legs for retaining the face mask bars therein. A coupling mechanism having a female member structured to be secured to the helmet and a generally T-shaped male member structured for mating engagement with the female member releasably secures the clips to the helmet. The female member includes a lower, partially externally threaded portion structured for insertion through a mounting hole in the helmet and mating engagement with an internally threaded locking member, an opposite upper portion structured to extend outward from the outside surface of the helmet and into a mounting hole in the clip, and an outwardly extending flange disposed between the lower and upper portions.

Abstract: A safety message announcing device is interconnected to a machine so as to make the machine inoperative until the safety message has been announced. A control signal is provided along with the safety message. A control mechanism interconnected to the start switch of the machine will only operate when the control signal is received. The control signal may take the form of multiple fixed frequency tones announced along with the message, with the control mechanism tuned to the tones to only enable the machine when the tones are heard by the control mechanism, thus assuring that the message has been announced as well. The control signal may take the form of a code that must be input by the operator before the machine will operate. This may be done with a visual as well as a sound annunciator.

Abstract: A radial arm assembly for mounting a power saw, the assembly comprising: a horizontally disposed base frame; two vertically oriented mounting posts disposed at opposite sides of an edge of the base frame; a cross-bar horizontally mounted on the posts at opposite ends of the cross-bar; an arm for supporting the saw, the arm being attached to the cross-bar substantially centered between the ends, the arm adapted to rotate over the base frame about a vertical axis, the arm comprising a guideway along substantially all of the arm; and, the saw being mounted on the arm and adapted to translate along the guideway, a blade of the saw being moveable with the saw along said guideway, unobstructed by either of the posts, and to and from a position substantially beneath the vertical axis, whereby cuts substantially corresponding to the full length of the arm may be effected.

Abstract: The present router guide has a guide plate for attachment to the base of a router with a central opening for passing the router bit. On the bottom, the guide plate has a series of openings spaced apart along a spiral of progressively increasing radius which has the central opening as its center. A pivot pin is selectively insertable into any one of these openings. This pivot pin has a pointed end for insertion in a workpiece at the center of a circular groove which is to be cut in the workpiece by the router bit as the guide plate is rotated about the pivot pin.

Abstract: The present router guide has a guide plate with a central opening for passing the router bit, and an eccentric periphery and a groove in the top extending parallel to that periphery. A slide is coupled to the guide plate at the groove and it presents a straight edge disposed beyond the guide plate for sliding engagement with a reference surface to guide the router bit along a path parallel to that surface. The slide can be clamped to the guide plate at any selected position along its eccentric periphery, thereby determining the spacing of the router bit from the straight edge on the slide. The coupling between the slide and the guide plate at the latter's groove keeps the straight edge on the slide perpendicular to a radius from the router bit out to the slide. The guide plate has a series of bottom recesses arranged in a spiral around its central opening and each providing a possible location for a pivot pin when the router is used to cut a circular groove in a workpiece.