Fig 7
On the front board, ten inches from top of bench, and about five inches from left edge, draw a circle one and three fourths inches in diameter; this circle when cut out should come as close to the leg as possible without cutting it.
To cut this hole take a five eighths bit and bore a series of holes round the inside of the one and three fourths inch circle. (See [fig. 7].)
The piece in the middle will fall out and leave a rather rough hole; but the edges can easily be trimmed.
Then take the board A (the three and one half foot piece), cut it thirty-one inches long. Square one end and then round it as at D. (See [fig. 8].) On the back side draw a pencil line through the middle; place the board against the left leg, with the sharp edge flush with top of bench, so that the pencil line will bisect the circular hole. Draw a similar circle on the board, and cut out as before.
Fig 6
Be careful in the doing of this, as the two holes must be exactly opposite for the screw to pass through. You ought to have two bits of wood left after cutting the legs and cross-pieces. Take one of these bits and put behind the front board on its two inch side and about three inches to the right of the left leg and parallel with the leg. It should just clear the hole. Fasten securely, so that it will cross the joint A. It will serve as a brace, and also give a level bearing for the wooden nut which comes with the screw and is wound on the end of screw after it passes through the two holes.
Your vise as it is will work all right for small pieces, but if you have a large article to hold, the loose board b will not keep its parallel position, for the thickness of the object you have in above will throw out the top end, and the lower end will of course swing in. To remedy this and make your vise adjustable to work of any size, you must do one more thing: