doublegunshop.com - home Forums General Discussion DIY Gunsmithing @ doublegunshop.com Making a pair of Victorian gun case Turnscrews

This post is starting to look like a visit from an old friend from my past.
The answer has many explanations, so here goes what you call "V" ground is in fact called hollow ground because this profile will fit the slot at the top tightly and in doing so reducing the screw driver (Turnscrew)from caming out as it is turned. Now the why, Victorian gunmakers of higher quality guns made Pins (Screws as they called them) with a very narrow slot in some cases down to twenty five thousands of an inch wide. This stupid width of screw slot usually ruled out the use of a parallel bladed screwdriver that us maar mortals use. Now this narrow slot type of screws are fine when assembling a new gun and of course the maker of the gun had a good supply of screws if the gun was returned for servicing. Now let us take into account time, one hundred years plus rust dirt and the every day parallel bladed screwdriver. Now there are two ways to go adjust a parallel screwdriver to fit the slot but disaster will usually arrive when you try to turn the screw the thin blade will either snap or bend depending on quality or temper. Next is the frustration go to method just get the screw out in any way possible and cover up your butcher job by using a hacksaw and making the slot wider for a parallel bladed screwdriver as in the photograph.





This is my what I think is a rather nice looking gun showing the signs of a Bubba strip down and screw head butchering session all because the maker made screws with such narrow slots. Now just to make things clear I could have made a set of new replacements but I am a big be leaver in "Aa Gun is only original once" and as the screws still do what they are intended for and original best left with the gun. And looking at the next photograph such small damage to screws taken the overall look of the gun is immaterial if you are like me can live with it! Modern gunmakers do use a more sensible slot size but it is still advisable to use a hollow ground screwdriver blade fitting the slot tightly at the top.




Hope this answers your question

Ernie

So, bottom line, the screw slots are narrow because they could make them that way. Fair enough, I can appreciate wanting to show off skills.

As to the turnscrews, if I understand correctly, the idea is to fill the top most portion of the slot with a blade that is thick enough to withstand the torque being applied yet not bottoming out in the slot in order to avoid cam out.

Thanks

Damascus (Ernie) how are the screwdriver heads formed to shape, It is hard to see how they look, but I know that most amateurs that work on guns use a regular screwdriver that has a wedge-shaped head and that is why you see a lot of screws buggered up because of the wedge-shaped head instead of parallel shaped head to fit the whole slot.

Sorry I did not look at the rest of the article where you describe what I was asking. Thanks.

Salut,

Il n'y a pas de règles établies pour les fentes de tête de vis. Certains fabricants utiliseront une fendante conique, alors que d'autres utiliseront une fendante parallèle.

Sur les fusils Idéal, jusque dans les années 30, les fentes de vis sont coniques.
Beaucoup de têtes de vis sur ce fusil ont été détériorées en voulant utiliser un tournevis avec des bords parallèles.

Fendante : outil d'armurier qui sert à fendre les têtes de vis.