In many cases, the shaping blocks and other bottom tools for large work are kept in their places by the square stems of the blocks being in a square hole in the anvil; so that one shaper may be taken out, and another put in, without any key-driving. When keys are used, they are so fitted that their lengths shall be in a convenient position for driving the keys into and out of the keyways. If square stems are attached, they should be as large as convenient, to prevent them being broken off, and the junctions of the stems with the blocks should be curved; consequently, the entrances to the square holes are curved to fit the stems.

For the convenience of lifting shaping blocks and other tools while being taken to, or away from, their places, several holes are made around the sides of the blocks to contain the ends of levers that are held by the men while carrying the blocks; or the holes may be required for the ends of the hooks, when the shapers are lifted by means of a crane.

After the shaping implements are lifted to their places, they are usually fastened with keys, represented in Fig. 250, if the blocks are without square stems; and the keys are driven in either at the sides of the dovetail gaps or at the bottoms. When the key is fixed at the sider the block is made to bear tight against the opposite side of the gap ; and when the key is driven in at the bottom of the gap, the block is made to bear against both sides of the dovetail; and during the hammering, the key sustains the force of the blows. A shaper fixed with a key at the bottom is denoted by Fig. 251. A key in this situation requires to be almost parallel, and is therefore troublesome to drive in and out; but a key at one side, through not sustaining any of the force of the hammer, may be considerably taper, which renders it preferable to a key at the bottom. Bottom keys are only suitable for blocks that do not require frequent fixing and unfixing.

All keys for shapers require to be of steel, and very smooth; also possessing curved extremities or boundaries, to resist injury through hammering into and out of their places. The two keys in Fig. 250 are fitted with a taper of about one or two degrees, if not intended to be often unfixed; but to allow an easy driving, the taper may be five or six degrees, and the key prevented from slipping back by means of a split key in the small end of the shaper key. The split key has a handle, to permit its being easily pulled out and put in when necessary.