Quality of Locks.—It is impossible to judge the quality of a gun lock by a mere examination, for if the metal be not the very best and the workmanship be also good, some portions, as a spring, may grow weak and in an unguarded moment give way. If the mainspring be not thoroughly tempered it may break the first time it be used on a frosty morning. It is well to see if the attachment of the stirrup or swivel be well made and fitted, as this controls the movements and play of the mainspring. The fitting of the sear spring on the sear is important. If too much cramped, it may give way; if not enough cramped, then it may grow weak and there will not be that sharp, clear click that the admirer of a good lock likes to hear.
On the hanging of the swivel or stirrup depends the smoothness of play of the mainspring. On the placing of the hole for the sear-pin depends the sweetness of the sear operating on the tumbler. On the pitching of the sear depends the cutting of the notches of the tumbler, and on the formation of the first notch depends the liability of the lock catching at half-cock when the trigger is made to be easily pulled from the full cock notch. On the formation of the half-cock notch depends the safety of carrying the arm at half-cock.
The Back Action Lock.—There are various forms of gun locks, and each form has its admirers. The back action shown in Fig. 43 admits of the arm being put together more strongly and securely than any other plan. Other advantages claimed for it are that the mainspring can be made longer and will therefore be less liable to break, and by such length has a smoother working motion to the hammer. As the lock plate is almost entirely surrounded by the wood of the stock, there is less liability of wet getting into the interior, and this may especially be the case as the hand, in carrying the gun, covers some portion of the lock.
Figure 43.
The Bar Lock.—This lock, Fig. 44, is so called from a bar formed at the breech end of the barrel, and to this bar the lock is fitted. The great advantage of this lock is that it admits of the stock to be so shaped that the grasp of the hand naturally tightens as the gun is raised to the shoulder. The objection raised by some to this lock is that it is more pervious to wet than the back action lock.
This lock possesses the advantage of having an arm of the tumbler so made that by the swivel or stirrup being hung upon that when the lock is at full cock the weight of the spring force is lessened by the arm acting as a lever to bring the moving force in the immediate vicinity of the axis on which the tumbler turns, and when the spring is bringing the hammer down on the nipple, increasing that force by divergence. It is sometimes called the Full Bar Lock.
Figure 44.
Side Action Lock.—In Fig. 45 is shown another form of lock, commonly called a side action. The mechanism and arrangement is similar to the full bar, but it has a shoulder that fits up to the barrel. If the gun be fitted with a plug or cylinder a suitable half round recess is cut in this shoulder to receive the plug.
Figure 45.
The Wesley Bar.—The Wesley bar shown in Fig. 46 differs from the common bar lock by being of different shape at the fore end, and this end does not fit up to the barrel like the bar lock. By the wood almost surrounding the plate, the interior is pretty well protected from wet. It has the same merit of the stock being so shaped as to tighten in the hand when raised to take sight. This lock has one objection, the wood between the lock-plate and barrel has to be cut so thin that the recoil of the gun is very apt to break and splinter it.
The Central Lock.—There is a grade of guns made with locks enclosed in the breech, or a continuation of the breech, in the same manner as common revolvers and other pistol locks are made. A view of this lock is given in Fig. 47. The principle is much the same as the back action lock when the hammer is placed on one side as in the back action lock. One side of the frame has the same office as the lock plate, and the other side supports the tumbler and other parts the same as the bridle. The formation of the tumbler is such that no sear is necessary, the trigger bearing directly against it; the point of the trigger having the same office as the nose of the tumbler, a small spring keeping it to place to catch in the tumbler notches. Generally this form of lock has the hammer placed directly in the central line of the bore of the barrel, and when so placed the lower end of the hammer has the same office as the tumbler and is shaped and has notches cut as in a side lock tumbler. As this form of lock has few parts, and has a long feather-like mainspring, it is easy and pleasant to operate.
Figure 46.
Cleaning Locks, etc.—While the gunsmith will be called upon to clean and repair various parts of fire-arms, the lock is the part with which he will have considerable to do. And, in most kind of guns, it is the most complicated part, and, consequently, the most difficult part to manage. Not a few gun-owners look upon it as a kind of mystery without the range of ordinary comprehension, hence they carry it to the shop, not only at the slightest indication of “something wrong,” but so often as it would seem to need thorough cleaning and oiling. This is all well enough, for the gun as much as anything comes clearly within the application of the rule which admonishes that “a stitch in time saves nine.” All of which being the case, one of the earliest things that the gunsmith will be called upon to study will be
Figure 47.
How to Take Down a Lock.—Having removed the lock from the gun, set the hammer at full-cock. Apply the hand-vise, or mainspring clamp, if he has one, to the mainspring, having first placed a bit of chamois skin or felt between the jaws of the vise and the spring to prevent bruising or scratching the polished surface of the latter. Turn up the vise gently until the hammer feels loose. Now press upon the sear-spring and let down the hammer. The mainspring is now entirely loose, and may be lifted out with the vise. This ends the complication of the lock; it is now only a plain machine, with parts held into position by screws, which may be removed one at a time until every piece has been taken from the plate.
In taking down a lock the beginner should work slowly and cautiously, thinking in every case before acting. His screwdriver should be pressed well-down in the notch of every screw to prevent damage to the head, and if he apprehends the slightest danger of getting “things mixed,” he should lay each screw and its piece in different places upon his bench. Of course, there will be no such necessity after a few locks have been taken down, but such a necessity might exist at the very beginning; at least there is no harm to grow out of taking what is known to be the safe side in every case.
The directions given for taking down, refer to the common lock, while locks of some of the modern guns will be made on plans quite different. But the principle will be the same, and hence there is no reasonable demand for going into further detail. The first object will be to get control of the mainspring so that it can be lifted out with ease. This attained, and all the rest of the work is easy enough.
To Clean and Oil the Lock.—Botches usually wipe the old oil and dirt from the parts with a rag, put on fresh oil, and then put the lock together again. This is a poor way, for a portion of the old gummy oil will be left to combine with the new, thus soon making it about as bad as the old. Every part should be thoroughly cleansed and dried before any new oil is used. First wipe the dirt and old oil off as thoroughly as possible with a piece of cloth or felt, and then rub it over with powdered chalk or Spanish whiting. Next brush off and rub with a stiff brush such as is used by jewelers or watchmakers. This will remove all the old oil, after which the new oil may be applied.
Cases may turn up in which the lock has been long neglected, and the oil and dirt have gummed together so badly as not to admit of wiping off. In such cases the parts should be soaked for a short time in kerosene or in benzine, which is still better. This will dissolve the gum and render it easy of removal.
In oiling, only oil enough should be applied to lubricate the parts—there is much more danger of getting on too much oil than too little. It should be put on with a stubbed camel’s hair brush or pencil, as the painters call it, and with extreme lightness. And there is but one kind of oil fit to be used on a lock, the very best “watchmaker’s oil” obtainable. Such an oil is comparatively costly, but a single bottle, costing 25 cents, will oil hundreds of locks, hence the cost is really not entitled to consideration, on account of its being so decidedly superior to any other oil in use.
How to Put up a Lock.—In taking down the lock the last thing removed was the sear-spring, perhaps—it is most convenient to make that the last thing. Now, in putting up the lock, that is the first part to claim our attention. Screw the sear-spring into position, then the sear; next put in the tumbler, and then put on the bridle. Having this all right, screw on the hammer and let it down. Then take the mainspring, clamped as it was at the taking down, hook it on to the swivel, and bring it up until the little steady-pin is in its hole in the plate. Now unscrew the vise and the lock is ready for work.
It will be necessary to always handle the mainspring with care. It is the first thing to come off in taking down, and the last to go on in putting up the lock; and the vise or clamp must be turned upon it only just enough to bring it loose, and no more. If more, it may be damaged, possibly broken.
Handling the parts of a lock with chamois skin or paper, is a good idea, while brushing off the chalk and rubbing them clean with the brush, and it is also a good idea not to touch them with the naked fingers afterwards. Few gunsmiths would be inclined to take this precaution, but it is worthy of consideration if one desires to be ranked among the very best and most careful of workmen; as handling with the naked fingers is apt to leave the parts in such a condition as will cause them to eventually rust, slightly at least.