patchbox hinge

[Acer Saccharum]

I have made my hinge. It works great.

But!

When I curve the finial to fit the gun, won't that cause the hinge to bind? Should I not be concerned?  Or do I have to make this differently?



Thanks,

Tom

[Benedict]

I have made my hinge. It works great.

But!

When I curve the finial to fit the gun, won't that cause the hinge to bind? Should I not be concerned?  Or do I have to make this differently?

Thanks,

Tom

The active part of the hinge must be straight to operate.  If it is curved, it will either bend straight when you operate it or it won't operate.  Having said that, you need to file some relief in the lower part of the knuckles and expect it to open up a little when you bend it.  It is an interesting compromise.

It looks good so far.  Good Luck!

Bruce

[rich pierce]

It's always best to make the hinge area as flat on the stock as possible.  The hole or channel in the hinge needs to be a little bigger in diameter than the pin.  Then bend, file where it binds as said on the underside, and peen a little on the topside to fill the gaps that open up.

[Jim Kibler]

It seems to work best if you roughly bend the box and finial to shape prior to cutting the hinge.  Otherwise gaps will likely develope when you bend it.  Like others have said, try to keep the hinge as straight as possible.  With five nuckles across the hinge, it's best to keep the outer two on the finial and try to keep most of the bending towards the outside of the finial and the lid.  Keep the working area of the inner three nuckles fairly straight.  With your arrangement of seven nuckles, this complicates thigs a bit since if forces the outermost nuckles on the lid towards the edges.  One other thing to note is that you sometimes see the lid and final have a fair curve but straighten out in the vicinity of the hinge to allow it to work well.   Look at some original examples and you'll probably see this.  Hope this may help.

[Acer Saccharum]

Thanks, gentlemen. I am hoping that the hinge will look OK when I'm done with it.

You know, now that I think about it, some of these assemblies have cast finials and separate hinges riveted on. This could allow curved final and door, but a straight hinge pin in the critical area. The rivet tab part  could be filed to fit the curve by filing rather than bending the knuckle area and pin to make the curve.

Tom

[Acer Saccharum]

Looking around RCA, I see a number of doors with 2 tabs on them........

They knew something I didn't...until now! 

[Tom Currie]

Tom, Are you going to let us in on what are you building ?  Looks like a rather short finial, maybe an early 2 piece piece box ?   

[Acer Saccharum]

Tom, this is my "Faire Gonne", the gun that has been a 'back burner' gun for about four years, one that has been to numerous gunsmithing demonstrations across the county. It is now taking shape and capturing my imagination.

Patchbox cavity, nice and deep. I can fit a summer weight sleeping bag in there.


Stock profile, thick wrist, early looking.


Christian Springs/Lehigh-ish sideplate. This panel does not match the lock panel.


Jim Filipski has been daring me to make my lock panels smaller. There is not much more I can take off. Chambers Germanic, with the full banana left on.

[Acer Saccharum]

So I am thinking of re-making the hinge, the two piece box will be four pieces: two hinges, finial and cover.

This way I can dome both finial and cover, and then file the tabs of the hinges fit the curvature of the cover and finial.

[rich pierce]

I'd make it like RCA #57- 2 pieces, each one folded over to make the hinge then more of the tab riveted to the brass plate.  Overkill.  That seemed to be a feature of the early brass boxes.  I'd bend both pieces then file the knuckles out to mate each other after the bending. Your stock is not that curved where the hinge will lie, if I'm seeing it right.

[Acer Saccharum]

Rich, I also see that #57 RCA has two narrow tabs on the cover hinge. This by itself will greatly simplify the working of the hinge.

[Dphariss]

I have made my hinge. It works great.

But!

When I curve the finial to fit the gun, won't that cause the hinge to bind? Should I not be concerned?  Or do I have to make this differently?



Thanks,

Tom

Good looking hinge.
It will work OK but when bent the gaps in the hinge will open a little and may require a little refitting to make it work smooth. If you can make a hinge this nice you can handle that no sweat. I like to bend then fit. I use  inside/outside contoured wood blocks.
A small diameter pin of piano wire will form to the curve of the stock. Piano wire is a lot easier to work with here.

Dan

[Dr. Tim-Boone]

Having played around with these last winter as a beginner, I am a firm believer that five tab hinges are the easiest to get to work smoothly and keep from having picket fence looking hinges. I would just leave the two outside tabs on the finial off. Course I guess it depends on what style the original patchbox was.

Do you have a picture of the patchbox you are replicating?  I would like to see how it was done.

[B Shipman]

At the risk of repeating what has been said, here is my sequence.

Make hinge.
Silver solder tabs.
Cut the finial.
Bend the whole thing to roughly fit the stock.
Pound the hinge roughly straight.
Cut the knuckles.
Ream the holes for the proper size pin and place the pin when the knuckes line up.
On a 4 piece box, the end knuckes can be bent if the vise covers the seam. Other than this any bending at this point wil either open the hinge or jam it.
The curve is obtained mostly by filing.

[Acer Saccharum]

Bill, I must have been making my new hinge while you were typing your reply.

I got pictures along the way, but this is the end result. .06 brass, curved finial and door. Seam is tight when shut; when the door opens, so does the seam.


I formed the barrels over .062 wire, but the pin now is about .04. I don't know if I could get the .062 wire back in; if I could, would the door open? I doubt it.


Soldered folded over and doubled hinge area. I like this a lot more than the plain single barrel I made at first.

[Acer Saccharum]

Hinge forming block, thanks to Mark Elliott. I think Mark had a tutorial on hinge forming on the old ALR. Anyway, I made up one of these for getting that nicely formed hinge barrel. It has a a round top tab, about .08. The hole closes down as you work the hinge, so it's good to start a little big.

Making the sharp inside corner. anneal after this step.


Formed corner and forming block


block and hinge clamped up


gradually pry the tab up with a chisel, until you get the tab up high enough where you can use the hammer on it.


tab bent up and over the bead of the block


Partially formed barrel. Anneal when this step is complete. Now scrub both inside faces clean, as they will be soldered after the last step.


Hold wire in groove with a turnscrew while tapping tab over with a hammer.


peen tab over until snug. A music wire pin is necessary, or you will have trouble pulling the pin after you're done forming. Pull the wire, and hard solder the seam.

[rich pierce]

Looks good and stout.  Overbuilt like most early brass boxes.

[Acer Saccharum]

I swain, the patchbox on the Kuntz rifle in the Met is only .025. Tissue paper. The entire finial and related brasswork is all light gage metal. Strange. It seems later the gun, the thinner the metal.

[Tim Crosby]

 Great set of pics.

 Thanks, Tim C.

[J.D.]

This has been a great thread. I'm preparing to do a PB with a captured lid, and was pondering the best way to make the hinge. I ponder no longer. 

Thanks and God bless

[David Veith]

The lip on the forming block how long is the lip? looks to be about 3/32 or is it bigger

[Acer Saccharum]

J.D. What I have shown is ONE way to make a hinge.

Simple barrels formed from finial and box(my first example).
Barrels formed from box and finial, with extended reinforcing barrel tabs, soldered (my second example)
Separate hinges, either cast or formed, attached to finial and lid, riveted and soldered.
Cast lid and finial with integrally cast hinge barrels.

[Acer Saccharum]

David, I measure .067 in height off the flat surface of the block. In width, I get .063. I rounded the top corners of the bead off with a file. I made my block too narrow, but I was able the work it back and forth to get the whole finial.

[flintriflesmith]

Once again I find myself jumping in the middle of a thread with an observation that belongs up front. It is entirely possible to make a curved patchbox hinge that works smoothly and had no gaps. I know the author of a popular book on gun making states otherwise but he is simply wrong.

Bend the curve in the brass (both sides of the hinge) to match the curve of the stock THEN cut and fit the hinge. I have taught how to do this at several NMLRA Seminars and someone in the class always points out that I have done something that a book says is impossible. I think it was the Navy CB's that had a saying, "the impossible just takes a little longer."

Gary

[Dphariss]

Once again I find myself jumping in the middle of a thread with an observation that belongs up front. It is entirely possible to make a curved patchbox hinge that works smoothly and had no gaps. I know the author of a popular book on gun making states otherwise but he is simply wrong.

Bend the curve in the brass (both sides of the hinge) to match the curve of the stock THEN cut and fit the hinge. I have taught how to do this at several NMLRA Seminars and someone in the class always points out that I have done something that a book says is impossible. I think it was the Navy CB's that had a saying, "the impossible just takes a little longer."

Gary

This is how I do it and fortunately I didn't know it was impossible.
I just figured there was no other way to get the right fit.

Dan