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Hardly just a screw, it is a gun part and can reveal a lot about the people that have worked the gun in the past. What will it tell about you?
It's Just A Screw
To a casual observer a damaged screw head is no big deal but to the Gunsmith it can cause depression, nightmares and substance abuse! Nobody knows it better than the Gunsmith that damaged screws are hard to repair or replace without leaving the gun looking repaired or modified. What we are trying to achieve is what the serious collectors call a "correct" gun. This means the gun shows no evidence of a repair or being dismantled for any reason. Look closely at the screws on the guns in your possession and you will see slots wedged wide and all sorts of damage from screwdrivers that didn't fit the slot properly. A potential used gun buyer takes this as evidence that the gun has been repaired at some point in time. Since gun people know that one part in a gun can't wear out without wear occurring to the other parts it is a reliable sign that the gun is worn and not worth the top price.
Gun screws are rarely found at the hardware store. Normally they are unique to each model and many times fitted to the individual gun. Quality firearms will have the screws timed so that the slots will be aligned with the center line of the gun. This might not sound like a big deal until you see a "best quality" gun with all the slots running the same direction and then look at a lesser gun with screws turned every sort of way. Always remember that it will be the small things that make the best gun special. They all have barrels, stocks, triggers and sights but they all don't have those special little custom touches like tiny little narrow screw slots and engraving that extends across the head of the screw. Imagine trying to replace a screw that you damaged that has a .030 inch slot and the head is angled to fit the frame of the gun. Now consider some delicate scroll engraving that will match when the screw is final position. Of course it will be color case hardened or nitre fire blue. No I'm not talking about screws in a cheap fixer upper but even trying to fit screws to these will take more time than the gun is worth. Bottom line is the Gunsmith has to take care of screws and make sure that when the screws are replaced in the gun there will be no damage or evidence that they were removed.
The way to remove these screws without damage is to make sure the screwdriver fits the slot. This won't happen with a screwdriver from the bucket at the checkout counter but only with a special screwdriver that has the tip ground to perfectly match the slot. These can be purchased or you can grind your own. The blade should fit the slot with no free play. It should be not extend all the way to the edge but as close as possible without contacting the sides of the recess for the screw head. The tip should be square without burs and the sides polished smooth with a slight radius. This will prevent the sides of the screwdriver from becoming a cutting tool in case it slides to the edge of the slot. It should be tough enough to flex like a spring when torque is applied and not bend but not so hard that it crumbles or snaps when under pressure.
If you want to buy Gunsmith screwdrivers you will usually get what you pay for so be advised that cheap isn't good and good isn't cheap. Most of the cheap interchangeable tip screwdrivers use tips that are too hard and brittle. Brownell's Magna tip drivers are excellent interchangeable drivers that hold up well and there might be others but personally I could never fall in love with this type of screwdriver. It always bothered me that the tip had a little wiggle. This doesn't seem to be a problem for most Gunsmiths and it's probably just me but a solid one piece screwdriver gets my vote.
Unless you buy a set that has 100 drivers you will need to grind a screwdriver to fit from time to time. Even if a screwdriver fits it will eventually need to be reground so it is necessary that a Gunsmith knows how to grind his screwdrivers.
For best results the bench grinder will need to run smooth and have wheels in good condition. The screwdriver is held with the tip up and grasped above the handle unless the blade is short. The holding hand can rest on the grinding table and each side of the blade is presented to the wheel with a loose grip on the wheel so the operator can feel the flat of the screwdriver as it rides against the wheel. The tip of the driver can be wagged like a dogs tail left and right but it should not move up or down. The tip will be hollow ground with a radius to match the contour of the wheel. Pay close attention to the sparks. Most are thrown clear but a few will be embedded in the surface of the wheel and these will be your indicators when your grind reaches the tip. When you see these sparks bouncing off the top of the blade it means the hollow grind has reached the tip. Go slow and don't allow the tip to take "color" or you will have lost your heat treatment. Of course it goes without saying to use all safety precautions and great care. Grinders are dangerous if you are careless or untrained!
If you have already damaged the screw it is too late to fit the screw driver except for the next time. First examine the screw and see if it can be repaired. Many times the slot can be recut with a screw head file and the screw polished and refinished. If it must be replaced ordering a replacement is the first choice. If none are available fabricating one from a blank screw kit might be an option. These are available from Brownells and maybe elsewhere. They come without threads and in slotted and hex head styles. Using a die you can make your own threads but I like running a few quick passes with the lathe and then chasing out the remainder with the die. This seems to keep the threads centered on the shaft better than using just the die. Screw head slotting files are expensive but nothing else I have tried seemed to work. When used with a screw slotting jig it is hard to end up with anything but a perfect slot.
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!
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