The third pattern is a common form of open end wrench and is shown in Fig. 11. The block for this pattern should be about 9 1/2" long, 2 1/2" wide and 7/8" thick. The face side, joint side and third side should be planed up and tested. Set the gauge at 1 1/8" and mark a centre line on both the wide surfaces, gauging from the joint side the whole length of the block. On this centre line

Figs. 11 and 12. Open End Wrench.

measure off a point 1 1/8" from one end of the block. This point will be the centre c, Fig. 12, for the circle outlining the head. With the try square and knife mark a line through this point across the face side, next duplicating the line on the opposite side, squaring from the joint side. Measure off and make a line on the opposite end

7 9/16/ from the first cross line drawn. This second point d, Fig. 12, will be the centre for the half circle outlining the handle. Set the compasses at 1" radius and scribe a circle with c, Fig. 12, as centre. Mark this circle on both sides of the block. Next set the compasses at 7/16" radius and with d as centre, scribe a half circle on both sides of the other end. The remainder of the outline of the wrench is next to be drawn, following the dimensions given in the figure.

Having drawn the outline on both sides of the block, bore a hole with 7/8" auger bit as in Fig. 12. With a hack saw make cuts at a, Fig. 12, to meet the hole just bored. With a suitable chisel finish this opening down to the line, as there is now less chance of splitting this end of the block, beginning at c, Fig. 12 for the same reason. When this is done, make two saw cuts at b, Fig. 12, and rough down the block with a chisel. In finishing the curved fillet near b, begin with a medium sized gouge and finish with a half round wood file.

After completing the outline, gauge two lines on the edge of the handle, each 3/ from the broard surfaces, to designate the thickness of the handle. With the parring chisel remove the portion outside the lines, cutting true to the lines and straightening across, leaving " next to the outline of the head, to afterward form a fillet where the head and handle join. This fillet may be formed with a very small gouge or a round "rat tail" file. Remembering that the face side is to be the top side of the pattern when removed from the mold, give the necessary draft to the pattern, not forgetting the opening at the head end of the wrench. Sandpaper the handle length-wise, placing the sandpaper on a block for all flat surfaces. Round the corners very slightly with sandpaper and the pattern is ready for finishing.