doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Hinge pin styles. Advantages/disadvantages?

So I�ve been trying to find the answer to this question, and have been coming up short.
I�ve noticed 3 different types of hinge pins.

1: A button-type, with a raised surface. (As seen on Berettas, Caesar Guerinis.)
2: A flush, smooth type. (As seen on Browning Citoris)
3: A flush, flat-head screw style. (As seen on Browning BSS & Sidelock)

Is there any distinct advantage of one type over the other? I�m asking primarily because I�m interested in the fact that Merkel went from type 3 to a type 1 on their new 43/40 model side-by-sides. I assume it cuts cost in hand-finishing, since you don�t have to index the screw and file it down, but are there any practical disadvantages to this style of hinge pin?

Different guns different joint or hinge pins .
Most Italian guns use the bifurcated style ie. a pin on either side that locates in a recess on either side of the barrel .
Browning and older Merkels had a through pin with a hook below the barrel .The screw head on a side by side that you see on the sides of the action is not a pin at all but a cover plate that would give access to the joint pin .Assuming we are talking about Holland pattern side locks , Purdey's and hammer guns or guns like the Parker not included .
All three have their advantages and disadvantages dependent on the style or type of action . Your point about the new Merkel is that it will have a shallower action than the older guns as is noticeable in the depths of actions between Browning and Beretta

Thanks, I learned something.

I'm trying to compare pictures of the new/old side by side Merkels, and whether it's true or the power of suggestion, the new ones do look a hair narrower, top to bottom.

I'd really like to know more about the topic. Are there any books you could recommend about double gun construction that would delve further into this?

I have a 1924-1927 Fabrique National d'Armes 16 ga sxs that has a screw plate over the hinge pin. You can take the pin completely out or rotate it and re-spot the set screw that is between the knuckle.



This gun also has Krupp Essen steel barrels.

L.C. Smith used a tapered hinge pin and I have only heard of a few ever being replaced.

Very interesting, thanks JDW.

There is a type of the type 3 in your OP & like the one JDW posted above that has the covers with a screw thread on each side of the action. There is also a little lock screw to the rear of the cover that is scalloped into the covers edge. When the lock screws & covers are taken off the pin just drifts out of the action, either way as it is parallel sided.
The cover plate threads are a larger diameter than the pin bore & that leaves room to ream the pin bore & simply press in a new oversized pin turned to the correct size that will put the barrels back on face. Screw covers back in place & the most simple re joint in the world has just been done.
I love the design. So much better than the English taper pin with engraved ends. What a PITA to replace.
O.M

Isn't that like what the BSS box lock had?

I have never had the pleasure of working on the BSS box lock but from looking at them I would say it is. Someone more knowledgeable on them may comment.
I have found this pin design on Spanish box lock doubles.
O.M