HRH Prince Philip 1921-2021 – a true supporter of fieldsports and conservation
Have you ever picked up a really nice airgun only to see the screws have been chewed? What a mess! You think to yourself, ‘how did this happen, especially on an otherwise nice piece?’.
A number of things can happen to allow this. Most of us don’t have real gun turnscrews – gunsmith screwdrivers. These have flat blades to fit into the flat slots on gun screws – easy peasy. General-purpose screwdrivers have angled blades - I have no idea how that came about but they all do and they fit general purpose screws that all have angled slots. Not guns crews. Most of us need these specialist tools but instead make do with using ordinary screwdrivers, taking extra caution by applying penetrating oils first, waiting for the oils to work in, then working carefully starting it, turning off slowly.
Mistakes still happen - slips, industrial thread lock on screws, distractions that can catch anyone out. Then the over-eager 'get stuck in' types just make things worse. Screws can seize, but surely there’s a better way to undo a stuck screw than to jam a screwdriver into it from every angle?
Most of us can all live with less than perfect, especially on a working gun, but really damaged screw heads can be so bad that despite best intentions they may be too ugly to keep and will certainly affect the value of a piece if swapping it. Worse still, if such a screw is still jammed solid it could make replacing it a right chore, needing more involved labour to remove it. Extreme heat from a torch, fast cooling, lots of little tools may start it turning eventually. For some screws, specialist help may be needed to drill it out completely. A vertical drill stand, a suitably small drillbit and lots of time taken slowly may add up to a drastic fix, but sometimes there’s nothing else for it. With care, a central hole can be drilled down providing a key for a tool, any tool that can bite in and start the screw turning. Having to do something very similar on a vintage car door still attached to its frame meant lying across the seats with a hand drill, probably the least fun job ever attempted as it was pouring down with rain at the time. Eventually, the drilled out screw came undone thanks to an old broken tip screwdriver.
This job on a small gun screw - if done too roughly - may damage the original threads needing either specialist epoxy putties to be used for repair or worse a new bigger hole may be needed, re-threaded with a tap and die set. The end result - one weirdly oversized screw that won't match any others, but still a decent working fix. Where there’s a will there’s a way to save an airgun!
Typically damaged screws look like the head has been widened out, and no screwdriver blade will key into the slot. Many here may remember trying in desperation to get such a screw turning by pressing hard down vertically, really really hard as if to move the screw by mind power alone. Psychologically some added grunting always seems to help. The usual result however is the screwdriver simply slips off the screw, damaging the screw even more and also the surrounds now as your hardened steel screwdriver has gouged into the much softer mild steel of the action or chamber or… We've all had that sinking feeling as the project now gets thrown with disgust into a box for another day.
If despite all the bad treatment the screw is now loosened and removed, a replacement can be ordered from one of the parts suppliers. However many older specialist parts can with time become discontinued meaning used parts need to be sourced from a salvageable donor. Whilst some may be tempted to break their gun up for spares at the merest hint of saving time and making a profit by selling the parts online, taking a second look could save a usable airgun. So to mashed screws. These can be filed and shaped back to an acceptable standard which will leave them certainly better looking and passable for when replacements can be found. They may even outlast the airgun if the intention is to clean up rather than to fully restore it.
Lining the jaws of a vice with two strips of wood, a screw or a row of screws can be held firmly but without damaging the screw's threads. A small lightweight hobby hammer is then used to tap the worse of the rough edges away. This working the surface is called peening and a peening or ball-pein hammer is the correct tool but here a hobby hammer has been used with care. Images here for clarity and brevity show the screw held in a model maker's grip but pressure needs to be applied downwards so a proper vice is always better.
Hammering the surface imperfections on the screw over the vice, very gently by tapping it repeatedly and lightly will slowly smooth the surface down. Then for the slot, it'll be wider than when it left the factory. A file can be used to clean the jags and unevenness then the slot can be cleaned out and if necessary made just a little deeper, enough for a screwdriver blade to get a purchase again. A full set of model makers files is invaluable for such repairs.
Using this method, most types of screw or fixings can be cleaned up to some degree. Placed in a flame from a gas torch the screw can be submerged carefully into oil; old car oil is allegedly better than new, giving the screw a proper traditional oil blue treatment. However if not done outside with safety precautions, this process is one guaranteed way to start a fire, so unless you want to spend the next year living rough in a caravan it’s probably prudent to use off-the-shelf cold gun blue solutions instead. The many different brands of these wipe on or dunk-in and dry off chemical solutions can each give a different colour and depth of bluing. This can depend on the chemical ingredients and also the composition of the steel itself. One good thing to come out of this pretty straightforward fix on screws is that these are an ideal testing subject if the decision is made to fully refinish an airgun later on!