Page:Popular Science Monthly Volume 89.djvu/790

 77G

��Popular Science Monthly

��Plane Blade Clamp and Emery Wheel Guide

WHEN sharpening a plane blade or a chisel i in. or wider, it is difficult to obtain a true edge even when both hands arc free; and since the advent of the small hand-power wheels it is still more difficult where only one hand is available for guiding the tool. The guide shown here is in- tended to counteract the difficulty.

The clamp which holds the plane blade, Fig. i, is made of iron, with the exception of a small oak sliding block. A strip of iron 8 in. long by i3^ in. wide and }/s in- thick can be procured at a hardware store or blacksmith shop. Heat it' red hot and bend it over an anvil or vise to bring it to the necessary form, as shown in Fig. I. When it is sufficiently cool touch up the rough surface with a file or emery wheel. Procure some J<^- in. round iron rods, cut them the required lengths, according to the design, and thread with a ma- chine-screw die, 14: in. by 20 or

24 threads. Make the holes for the ad- justing screws with a 3/ l6-in. twist drill and tap them with }i-in. by 20 or 24 tap. The handles on the screws are made of short pieces of nails set snugly in a ^ s-i"- hole.

The sliding block of oak on the horizontal ad- justing screw is about I in. by 1 3-^ in., and per- haps 3''2 in. thick, allowing sufficient <le[)th for the long screw to be seated in it. Make a small groove on tin- end of llic screw nearest the block and |)ul in u brad to keep the screw from drawing

���Fig. 1. The clamp which holds

the plane blade is made of iron

with an oak sliding block

��away fnjm the block. Before attaching the block, rabbet the lower corner which will overlap the plane or chisel blade, or inlay a small strip of fairly stiff brass in the top of the oak block, setting it with glue, .so as to form a wearing surface for the vertical screw, as when sharpening a narrow blade the oak block may come under the screw. In order to have the emery wheel and guide always in line and set up square it is well to have the wheel clamped to a board which can be used as a pcr- then the device can be

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��Fig. 2. The wheel is clamped to a board which may be used as a permanent base for stability

��fND VIEW OfRUHWAy

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��Fig. 3. The runway may be made of wood and should be twice the length of the sliding cl.nmp

��manent base; fastened to the workbench as a unit or hung out of the way when not in use. The runway itself is made of wood, as the wear is very slight. It should be at least twice the length of the sliding clamp. Have it about ij^ in. wide by 5i^ in. thick. With a rabbeting plane take ofT the top to the depth of J^ in., lea\ing a small raised edge about J s '"• by 3/^ in., which is to guide the clamp, as shown in the detail in Fig. 3. Another way would be to screw on a thin metal strip, raising one edge 'g in. above the top of the runway. Fasten a small angle iron at each end of the them to the sliding support on the right, and to a "jcQpcrmancnt sup- port on the other end. Small bolls with thumb mits will render the runway adjust- able, so that a b 1 a d e c a 11 be ground at any <lcsirr(l angle. The runway should be si t up at a |)erfecl right angle to the center of tiie wheel.

��runway. Secure

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