doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Hinge pin arrangement, explain?

A plea to the body:

Explain the possible hinge pin methods in common use for SXS shotguns. Removable, not, etc. I am familiar with tapered, driven out with or with out set screw. Threaded with slotted head. Not so much with covers or caps or irreplaceable like a Scott 700. I read somewhere of the Birmingham method, made in place and I assume not removable or replaceable.

Looking for some insight!

Thanks,

Chief

Looks like no responses so far.
All I know is that the Webley 700 boxlocks have a hinge pin that is not removable, but can be built up with some TiG welding and then ground down to size, which is expensive.

Over to you, gunsmiths...

What do you want to know?
I think you covered the basics.

Miller wrote of pressing out pins, and then reaming the hole while the barrels were tightly fit for 100% bearing on the hook.
Others pointed out that was unnecessary.

For the forged in place pins I remember seeing a drawing showing which areas of the pin were working surfaces, and which not. Which illuminated how they could be machined. And why some pins could just be rotated to give new life.

I think working a new cross pin down until it is flush with the action (without scratching the action) is hard to do, and worth paying for.

Beer can shims and loctite sure work well for non collectible guns.

If you are bored, you can plastigauge each side and see the clearance differences.

Then we can argue for months over cleaning and lubrication, vs recoil for the differences. Lol.

There are basically 3 types of hinge or joint pin ,
1 Solid ,as an integral part of the action body .Used by Webley and Westley Richards as well as many other maker in the past.
2 Loose pin which was driven into the body with an interference fit ,frequently with locking pins of some description .AyA still use this method for example .
3 Screw in .Self explanatory a pin that is threaded and screws into the action. These are depending on the gun a " through pin " as one that goes completely through the action , Purdey being a prime example .Or. A "hidden" pin that only goes through the centre part of the action with caps or cover plates to " fill " the holes on the action bars .On many boxlocks that used either a screw or knock in pin the caps could be removable or blind , as in fitted with no intention of them being removed .
Re-jointing any gun has to be considered on it merits , be it a new joint pin or welding up the hook ,depending on how far back the barrel needs to move .
I have tightened and re-jointed hundreds of guns building up hooks as well as making new over sized joint pins .
In some cases with knock in pins that have worked loose the hole in the body can become elongated so needs to be reamed out and a larger diameter pin made .Knocking out and turning has in my experience been largely waste of time .
As to jointing new guns with loose pins , it was the practice to joint with a slave pin ,then to ream through and fit a correct size matching pin .

I bought a Fabrique Nationale d' Armes 16 ga. with 30" Krupp steel barrels. I handled the gun in a Cabela's store near me and I really like the way it came up and because it was a 16 gauge, my favorite I bought it cheap. It was a little loose , off face, so looking into it there was a large screw over the hinge pin on the left side, this was just a cap removed it to find another screw that was the hinge pin. Could not loosen it and looked over it carefully and where the gun breaks there was a tiny screw that secured it and prevented the hinge pin from turning (how I don't know). Unscrewing the hinge pin I found out it was slightly egg-shaped so turned it 180 deg. and lightly drilled a new spot for the set screw. The gun is a pleasure to shoot as it weighs 6 lbs. 1oz., 65mm chambers (2 9/16") side clips, Greener cross bolt. Made 1924-1927?

The list doesn't include Parker who used a 1/4" stove bolt for a hinge pin.

Wow! That's amazing that you could do that work so well! And you ended up with a great gun. Good work!! And good luck!

another rather unusual hinge pin system, incorporates centrical sleeves that fit snugly over the central axle pin to provide the bearing surface. if they reach a degree of wear that requires attention, they can simply be removed, and replaced with another sleeve that returns to the desired clearances.

this system was used by franz jager on his verschluss guns, as marketed under the herold name, and licensed to several belgian and other european makers....when these guns were marketed (and parts were available), one turnscrew and 5 minutes could put a gun back on face. a similar concept was patented by j. d. dougall, for the lockfast design - very early in the development era of the breech loader gun....the significant difference being the fact that the sleeve was eccentric (and had to be keyed into the properly indexed position), and thus provided the step-back movement that led to the term "slide and drop" type actions.

i happen to have both a herold gun and a lockfast, and admire the sensible approach taken by dougall and jager to address this situation.

in similar concept, i think of the guns that utilize replaceable rear faces on their rear lumps - so that adjustments can be made "in the circle", without requiring exotic welding and machining techniques.

best regards,

tom

Gunman;

The poster above brings to my mind to a question (that I have thought about for a very long time) I have about your last sentence and "..it was practice to joint with a slave pin, then ream through and fit the correct size matching pin" I have known about this practice of the English gun trade for some years and I ask you this question. On a shotgun (as I know it is different on a double rifle) what is the min-max clearance between the circle and the draw that the actioner is targeting to attain in jointing a NEW gun? I have been led to believe it is a couple of thousands of an inch.

Kind Regards;
Stephen Howell

Hinge pin free:





Best,
Ted