ABC of the Steel Square and Its Uses

by Fred. T. Hodgson

Blade gives Cut of Jacks, also Sheathing.

These matters have been discussed at length, in trade journals and also in my larger volumes on The Practical Uses of the Steel Square, but the foregoing treatment of the subject is on somewhat different lines and will prove interesting.

John Wilberforce, Toronto, Ont., wants to know if a wreath piece for a single-pitch rail with level landing can be set out with the Steel Square.

Answer: Yes, the problem can be solved as follows:

Fig. 94.

Set out on a board the plan of the wreath A ([Fig. 94]). Draw the outside circle and the inside and center line of same, showing also the joints. Set out the pitch off the shank; square up the center outside and inside lines from the plan on to the pitch. The thickness of the wreath piece is found by drawing a section of rail under the pitch line B. Set out again the half-width of the well; square off the pitch lines to the half width; this gives major and minor axes of the ellipse, as shown in the development ([Fig. 94]). Lay the square on the axis. Get a light piece of lath, drive in a nail at the half major, and one at the half minor; describe the inner ellipse line on the piece of timber from which the wreath is to be formed; pull out the nails, and repeat the process for the center and outside lines. Draw the shank and also the point as shown on the board.

Fig. 95.

Now cut at the joints, allowing an ⅛-inch for the fitting of the joint after the wreath is cut and roughed out. Use another piece of timber about 2 inches thick, to form the bed block, and cut it to the pitch accurate and square in thickness. Screw or pin it to the under side of the wreath piece (see [Fig. 95]), taking care to get it parallel with the shank, and the nails in clear of the saw. Then proceed to cut the wreath with the band saw, beginning at the circular part, and work it to the shank inside and outside. This operation should be performed most carefully with a narrow band saw, having a strong set and strained tight, feeding very slowly. The wreath should require hardly any spoke shaving. Knock off the block and draw a chalk mark across the table, just in front of the teeth. The use of this line is to assist the operator to get the outside of the wreath always touching this spot in front of the saw. He must carefully lower his hand until it is down level at the shank end. The top is cut first, and the saw should skim along the outside top arris, giving a sweep that cannot be excelled in graduation of curve. Then set a gauge to the thickness of the rail, mark a line on the inside of the wreath, and cut as before. With a little practice a wreath can be turned off the band saw ready for molding. When the shank is too long, it is always better to nail the bed block on top of the wreath, and cut it upside down, thus getting the curve portion near the table. Then the shank can be run in with the band saw when the block is knocked off. The foregoing is for a single-pitch wreath as used for stairs with level landings and narrow wells. Where the rails are pitched both ways, the bed block has to be cut at the double inclination. (See preceding answers.)