Domed patch box

[Col. Batguano]

Guys,

I'm doing a domed PB on this current build. The question is; in the space between the PB cavity and the web of the butt, do you leave wood that conforms to the concave shape of the PB, or just take it down to be flush with the rest of the butt plate? I think I have enough wood proud to the butt plate to make it work.

Yes I know that the more wood I leave will make the hole through the remaining web for the pin latch more oval (actually sort of funnel shaped, vertical on the lock side, and angled rearward on the butt plate side if done perfectly) to accommodate the longer swing.

Also, when soldering on the end piece do you try and file it to conform to the inside part of the dome, or just solder it to the end? That's how I did my muzzle cap. Just soldered it on top of the complex shape of the muzzle cap and filed it down to conform. I figured it would have been too hard to get every little nook and cranny just right. But with a much more simple shale like a patch box dome, I figure it might be easier to get a good fit.

P.S.; it's a bought PB assembly, rather than one I hammered out and formed myself. Some times life is a little easier that way. It cost me about $8.00 more than starting with sheet brass, but I probably saved that much in contributions to the "swear jar" too.

So when it comes to the release mechanism, the originals seem to have the pin in the middle of the PB lid, and the release sticking out the rear. with a button on the right of the butt plate to move upwards to loosen the latch. How do you get the internal mechanism to attach to the inside? It seems the ideal place is on the top, or comb side to keep dirt and grit from falling down and jamming up the spring cavity. The bottom would be easiest, but that's also the wort place. The original was done in the middle. Unfortunately, I've not seen the pictures of the inside of the original.

The last one I did this way I did the pin on the top portion, which of course worked. I tinkered with the notion of putting a dog leg in the spring bar, but I couldn't fit that through to hole in the BP and be tight to the web, so the solution was to put it through the top edge, and just live with the off center silver spot showing through the brass.

 

[rich pierce]

The wood web should be flush with the buttplate. After all you inlet the buttplate then shape the stock then inlet the patch box.

The spring release often lies along the upper or "comb" side of the patchbox cavity. It is embedded into the front of the cavity and extends through the butt plate as you describe. Bends in the spring and a bulge in the cavity wall work together to make it exert some pressure toward the toe of the buttplate.

 

[Vaino]

On the couple I've done, the end cap is soldered as you did your Mcap....although I don't do my Mcaps that way. The final end cap shape has a 1/16" high extension on both sides of the dome so the end cap is as wide as the lid.

Whether you make the domed lid or buy it, the outline of the dome should be a sharp corner and I accomplished this w/ a long, hardened piece of steel which is hit w/ a hammer. The lid is backed up w/ a steel plate. The curved outline of the dome {nose} is also struck w/ the same piece of steel and then smoothed w/ riffle files.

Rich gave you good advice asre the lid release.....Fred

 

[Col. Batguano]

I did it exactly as you described on the last gun, but that one had a flush patch box. Man, that release mechanism took a lot of fine tuning to get it to work, and just about as much more after staining and finishing to get it to work again!

Just wondering if, since I had the wood to do it, if the wood should leave the "hump" under the dome. That would leave a cavity (sort of a 2-level effect) between the web and the box door, in addition to the one in the stock I'm going to dig out.

Ooh, that sharp edge to the dome really looks neat. Very distinct and clean. I haven't looked that closely on the originals for that. Now I will. I hadn't even thought of that part yet, but it's a great idea. Thanks Fred!

Do you have any pictures of the PB opened to show the inside and/or latch mechanism?

Ok, here's the throw away line;

What hump?

 

[Vaino]

Mine didn't have a wooden hump....just a straight surface the width of the lid and the depth into the Bplate was whatever the mat'l thickness was.

Use brass that's 1/8" thick for the end cap....it can be filed down to fit the curve of the Bplate.....Fred

 

[Col. Batguano]

Good idea on the thicker brass for the end. I think the piece that came in the package is more like .050"-.062".

Does your cavity in the stock at all mirror the shape of the dome?

 

[Vaino]

The Pbox cavity in the wood is the same as all the cavities whether or not the lid is domed....Fred