Those glands with circular flanges or oblong ones, are usually much larger than those having hexagonal flanges, and therefore need a somewhat different treatment.

A large gland, or a large packing-bush, should be bored and entirely turned without using any arbor or spindle for turning the outside, the entire outer surface being turned while the article is fastened to the lathe-chuck. By this means, the lifting and moving of a heavy slide-rod, piston-rod, or arbor, is avoided, and therefore the fitting, fixing, and unfixing of an arbor to the glands and bushes, is also avoided.

Large glands frequently consist of cast iron, and are furnished with friction bushes of gun-metal. Such a gland is bored so that the hole is larger in diameter than the diameter of its rod, that a bush of proper thickness may be put into the hole and remain between the cast-iron and the piston-rod or other rod. The bush or tube is turned to cause its outside to tightly fit the hole in the gland, and may be bored to fit the rod either before it is put into the gland, or afterwards.

A gland which is provided with a bush, and is truly made, can be easily repaired when the hole has become worn too large, at which time the old bush can be taken out, and a new one put in, without in any way altering the hole in the gland. It is therefore proper to accurately form the outside of the gland concentric with the hole, at the first making.

The form to which the hole of a gland should be bored for a bush, is depicted in Fig. 1010, in which the shape of the hole is indicated by dotted lines. It will be observed that the mouth of the hole in the outer end of the stem is furnished with a recess which is of greater diameter than the remainder of the hole. Such a form will allow one end of the bush to be rather larger in diameter than the other end, and when the bush is in the hole, the larger part will be a sen of head which fits the mouth of the gland-hole and prevents further shifting of the bush. During the use of the gland, its stem will be forced upon the packing, and therefore the pressure will merely tend to tighten the bush in its place.

The shape of a gland-bush is depicted by Fig. 1011. It may be here stated that a bush of this form may be used in two ways. It may be turned so that its head or flange is but little larger in diameter than the remainder, and be suitable for the hole shown in Fig. 1010; or the bush may be turned so that the diameter of its large end is equal to the diameter of the gland-stem. If thus shaped, the hole in the gland is parallel, and the entire flange or head of the bush will therefore remain outside the gland and in contact with the bottom.

In order to turn a bush to fit the gland, it is put upon an arbor without boring the hole, the arbor being made to tightly fit the rough hole, and when together appearing as in Fig. 1012. But when it happens that the hole is not cast concentric with the outside, and there is not much superfluous metal to remove, it can be first bored in a cup-chuck, while the outer surface rotates truly, and next turned while on an arbor, to complete the shaping.

A bush having its hole not true with the outside can also be turned by means of a middle-bolt or centre-bolt. This is a screw-bolt and nut attached to the lathe-spindle with a key at one end, and having a nut and washers at the other end to bear upon the bush and hold it to the chuck while being turned. In Fig. 1015 a centre-bolt is seen in use; but in this Figure the bolt is employed to force a bush into its hole. If a bush is thus held tight to a parallel ring on the chuck, the outside can be easily adjusted true, after which a few poppets can be placed, if the bush is large, to grip the large end while the stem is being reduced. The middle-bolt requires ample space around it, to allow the object to be easily shifted to the exact place desired; consequently it may be necessary to first enlarge the hole to a convenient size with a drilling-machine previous to fixing it to a lathe.

In order to prepare a large gland for its bush, it may be firmly held to a disc-chuck, as represented in Fig. 1013. It will be seen that the flange is in contact with a pair of parallel blocks, and that the object is held to the chuck with a couple of plates and bolts. These are the first fastenings, and hold the gland a short time till other plates are fixed, and poppets are put to the edge of the flange. At this fixing it is necessary to turn the outer surface of the stem, in addition to boring the hole for the bush. This will cause the hole to be concentric with the outside, and will also provide a true surface by which the article can be again truly adjusted on the chuck a second time.

The second fixing of the gland is necessary after its bush has been fitted and driven in, when it is again put to the chuck for boring the hole in the bush, unless the bush was before accurately bored and has been turned while on an arbor, in which case the gland is fixed to the chuck to have the dish shaped. In order that the gland may be quickly adjusted the second time, it is necessary to bore and turn the entire stem, at the first fixing, to its finished diameter and length ; the dish which is to grip the packing should also be roughly shaped, and the surface or shoulder of the flange adjoining the stem is also to be turned; this is done by means of a centre-bolt and small poppets whose screw-points bite the edge of the flange, as seen in Fig. 1014. This arrangement allows the flange to be entirely free from plates, and therefore can be entirely turned.

When the gland-stem has been finished, and the hole properly shaped for the bush, the gland may be removed from the chuck and the bush put into its place. The gland is next fixed to the chuck the second time in the same position as before, and the dish in the end of the stem is now smoothly finished to the desired shape, the superfluous end of the bush being cut off until it exactly coincides with the cast iron, supposing that the bush is without any flange projecting outside the bottom of the stem; but if it is furnished with such a flange, the entire dish is contained therein, and it must therefore be thick enough to admit a dish of proper depth.

In many cases this second fixing of glands can be avoided. To do this, it is necessary to have the bush turned previous to finishing the boring of the gland; and while the gland yet remains fixed on the chuck the bush must be forced into its place. To effect this easily, it is carefully turned to the proper size by accurate measurements, and is put into the hole by using a middle-bolt. A bolt in use for this purpose is indicated in Fig. 1015, and is of sufficient length to reach from the lathe-spindle to the outer end of the bush when it is entered about half way into the hole, which is the condition of the bush in the Figure. On the outer end of it is situated a plate having a hole in the middle, through which the end of the bolt extends to receive a nut. The nut bears upon the plate, or perhaps upon one or two washers, and the plate bears upon the bush ; therefore, by screwing the nut with a spanner the bush can be slowly squeezed into the gland with but very little hammering, if it is not too large. Hammering should be avoided as far as possible, because it shifts the object on the chuck ; and the small quantity of hammering that may be required should be applied to the plate which is in contact with the bush, and given every time the nut is advanced a short distance by the spanner.

The last fixing of the gland to the chuck is performed after the stem is finished, and the bush also finished ; and this fixing is necessary for turning the outer or top surface of the flange, and the oil-cup or dish, also whatever ornamental ridge may exist on the flange. This turning is done while the object is held with its stem tight against the chuck, as seen in Fig. 1016, if comparative large and long poppets are accessible, and the object is not large or consists of soft metal. But in some cases it is preferable to put the gland with its stem into a parallel ring, as seen in Fig. 1017, the ring being of sufficient length to cause the flange of the gland to bear upon one flat face of the ring without allowing the bottom of the gland-stem to touch the chuck. Instead of a ring, parallel blocks of proper height should be used for large glands; and this mode of fixing firmly holds the object, because the broad surface of the flange is in direct contact with the parallel blocks. The middle-bolt shown in the Figure keeps the gland and blocks tight to the chuck, while three or four poppets are fixed to bite the stem, as in Fig. 1016. The object is therefore in position to have the rim entirely turned, and also a part of the front surface adjoining the dish ; after this is finished, holdfast plates are fixed upon the flange, and the centre-bolt with its attachments are removed, which allows the dish and ornamental ridge to be turned true with the rim, because the gland has not been shifted, although the centre-bolt has been taken out.

A very convenient mode of turning the flanges of small glands, and other articles of similar shapes, consists in first boring and turning their stems, and next driving them into a wood chuck with the flanges outwards, the hole in the chuck being truly turned to tightly fit the stems, after it is finally adjusted and bolted to the disc-chuck. A wood-chuck fastened to a disc-chuck in this manner is denoted by Fig. 1018, and a gland is shown in the hole ready for turning, no poppets or plates and bolts being required.