Damaged screw heads: few things make an otherwise good gun look shabby more than buggered screw heads. Here's how to address them.
While we have done our best to repair a firearm, a set of botched screws is the mark of a gun butcher rather than a careful gunsmith. Even if the piece came into the shop in bad shape and we have restored it to the best of our ability, if the screws arrived on our bench beat up we get the blame if the firearm leaves the shop with buggered screws. Let's look at the damaged screws head and arrive at a means to make it right. A buggered screw head is often an indication that the rest of the gun is abused as well. Even though we have made certain that the piece is repaired correctly, we cannot really claim a restoration without fixing the screw heads.
Gun screws are unique to firearms. The hardware store is no help. Brownells is an excellent source and the original manufacturer sometimes has the screws on the parts list. The rub is you cannot run to the hardware store and find the right part and the old time gunsmith with a boxes of spare screws is increasingly rare. These little items are a big problem to find sometimes and it behooves us to learn to repair the head of the screw itself. You also have to learn how the screws are timed, that is, how the screws are properly aligned in the slots. This is pretty important and when you see a high quality firearm with the slots running correctly it projects the correct symmetry for a firearm. We have all done it--I certainly have--and you feel like a duffer when you damage or round off a screw head. Some screws are specially angled and a few have a special finish or engraving. It is darned difficult to clean up a mess with one of these.
The first thing we must do is to make certain that the screwdriver tip fits the slot. Some of us still grind our own. W. R. Grace & Co. makes a wonderful gunsmith screwdriver kit featuring blued screwdrivers with well scalloped handles. I treasure my set. The Chapman Professional Gunsmith Screwdriver Set is a classic that we all must have on the bench. It is cheap insurance to very carefully and lightly touch the screwdriver to the screw to be certain it fits. If the proper fit isn't in the house then grinding a screwdriver to the proper size is the safest way. Alter a time, you will have on hand a number of custom screwdrivers. They may not always be pretty but they are handy.
There is only one formula tor the blade geometry in a correctly fitting screwdriver. The blade tip must be perfectly square to fit in the screw slot. The sides must be polished and smooth. When grinding, be certain you have maintained a slight radius. The will act as a buffer that prevents the sides of the screwdriver from scratching and cutting if the tip is allowed to slide in the screw head slot. Avoid Chinese flea market screwdriver blades because the steel has to be good in order to hold some flex in it when we are working with a particularly recalcitrant screw. Flex is good, snapping under pressure is not.
After a time you will have a credible set of screwdrivers. Note that just because a screwdriver fits the first time it may still need to be reground, cleaned up and reshaped from time to time. Actually grinding the screwdriver head is an exercise in the gunsmith's art. Take the screwdriver tip up and hold it just above the handle. Some modification is needed for a shorter screwdriver, but I don't have much use for the truly short versions. The hand may be stabilized against I he table in most situations. Some left and right play is all right but the tip must not move up and down or there is a good chance the end product will not be viable for use. Understand the difference between a chisel grind, a convex grind and a high grind because you are looking to finish up with a hollow grind. Do not allow the tip of the screwdriver to turn plum purple or red or the temper will be lost and the screwdriver tip will deform when you are attempting to remove a screw that is dug in tight. Grinding is an art form that produces true custom results.
After finding a driver with the perfect fit, carefully try to break the screw loose. A bit of penetrating oil goes a long way in loosening the screw if the screw is stuck.
If the screw head is already damaged, well, a good screwdriver is irrelevant except when you place the repaired screw back in the slot. If the screw head has not lost its shape completely the screw head may be recut with a properly sized file. The easiest thing is sometimes to replace the screw by ordering a new one, but it all depends upon your time and the expense involved in ordering screws. Frankly, sometimes I have been surprised at the worth makers put on their parts.
There are good sources for screws but the repair of a screw head is always an option. Specific files that are designed to slotting screw heads can be expensive but then they are awfully handy when needed. It might seem like a lot of work at the time but screw heads that are less than perfect will attract a lot of attention and detract from the gun. You might think that if you do a good job nobody will know except you and the customer but in the gun community good work is appreciated and rarely goes unnoticed!
Another problem with screw heads is simply getting the screw out of the gun. There are a number of cures, including soaking the screws in penetrating oil and even applying heat. You can even put a gun part in the freezer and attempt to heat the screw while the receiver is cold to get a screw out. If that doesn't work, we'll go to other options.
The simplest is leaving the screw alone, provided the gun functions. If a badly-stuck screw simply must come out, a good cure is to warm the receiver and then cool the screw with liquid nitrogen or dry ice. You are expanding the hole with heat and shrinking the screw with cold. Another option to convince a part to break loose is lots of oil and steady pressure. After liberally applying Kroil, tap the screw gently with a wooden mallet, hold your mouth just right and often it will break loose.
An excellent repair for badly messed up screws is to use the drill press. Turn it off and do not use power. Secure the part on the drill press and be certain the offending screw is vertical. Grind a good screwdriver tip and use the drill press to keep the screwdriver tip hard in place on the screw and apply pressure until the screw breaks loose. You will need to apply penetrating oil first and be certain the screwdriver tip is a good fit. If you don't get it out at least it is on the drill press and you can proceed to drill the thing out.
Another remedy for a stuck screw demands a careful hand. This will usually ruin the screw but that might be your only recourse. Take a file and raise a tiny wedge on the screw head. Then take a sharp screwdriver and use a mallet to drive the screwdriver into the raised portion of the screw head. Tap the screw in the correct direction to loosen the screw and drive it out. The screw will be buggered but this works to remove it.
A good Forty years ago as a teenager I walked into a shop to have a revolver repaired. The man behind the counter took one look at the revolver and said, "This gun has been gone into." I replied, "Yes and you are the one that fixed it!" Don't be embarrassed in that manner. There are more glamorous things to be done with a firearm and many that are more profitable but nothing that will come in handy as often as handling screws and screw heads.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||BACK TO BASICS|
|Date:||Aug 1, 2013|
|Previous Article:||Custom firing pin for a Stevens single shot rifle: finding a firing pin for an old Stevens single shot rifle was unsuccessful. Making one turned out...|
|Next Article:||Scoping 1896 Mauser actions: drilling and tapping for Weaver bases on 1896 Mausers.|