Author Topic: Mountain Howitzer Plans?? (Read 1926 times)

Tigman · « **on:** July 22, 2006, 06:12:17 PM »

Any one have comments on the Buck Stix plans? Looks pretty well thought out to me except for a few small details. Any others out there to consider?

Thanks
Mark

Double D · « **Reply #1 on:** July 22, 2006, 06:53:34 PM »

I haven't realy analyzed Buck stix plans. Every time the subject comes up it gets drifted of onto what he did with the gun. That is off limits on this board. It is off topic. Any post discussing thatwill be edited by the moderators without notice, further or comment.

A discussion of how he built the gun is very much welcomed. If you can post a link so other can see what you are talking about...

Personally I would just get a set of plans from Antique Ordnanace Publishers. You will find them listed on the Where to find Cannons post stuck to the top of this forum.

GGaskill · « **Reply #2 on:** July 22, 2006, 07:52:05 PM »

He made a full scale mountain howitzer. From looking at only the materials presented on his website, the only barrel detail I really am not fond of is the plugged tubing. The interior joint between the plug and tube (the muzzle end, not the welded end) is going to be a place where corrosion occurs and it will be essentially inaccessible to address. Eventually it will become a safety hazard as a place for unextinguished embers to accumulate. If some way to effectively seal that joint is found, I would be satisfied.

My other complaint is with his carriage--a mountain howitzer stock does not have separate cheeks; they are part of the stock (at least on the pack carriage.) His carriage is more like a standard No. 1 carriage used by the Napoleon, Parrott rifle and wrought iron rifle.

CU_Cannon · « **Reply #3 on:** July 23, 2006, 03:48:27 AM »

I would go with the Antique Ordnance Publishers plans they are very high quality giving all the details needed to build an accurate replica. Buck stix website is a great resource for how he built his but I don’t think the drawings would be worth the price. The AOP plans are also much less.

GG as far as the carriage is concerned there were two different types of carriages; a mountain type carriage that would break down and a prairie carriage. The prairie carriage was more or less a scaled down version of a filed carriage. It was wider than the pack carriage for greater stability on flat ground. There was also the option of using a limber with this type carriage.

Michael Az · « **Reply #4 on:** July 23, 2006, 04:33:09 AM »

I know this post isn't about a mortar but I was astonished that a machine shop couldn't cut the relief for his trunion, but I guess it was an automotive machine shop. I was wondering what you fellows think about the way he mounted the trunion with four small screws.
Michael

GGaskill · « **Reply #5 on:** July 23, 2006, 09:07:50 AM »

The prairie carriage was more or less a scaled down version of a field carriage.

Thanks for that info; I haven't seen a prairie carriage although I have heard of them.

There are pictures of the trunnions welded on the barrel. Didn't notice the screws. I always weld permanent connections when I can anyway.

Michael Az · « **Reply #6 on:** July 23, 2006, 09:20:41 AM »

He also made a nice looking mortar and that is the one I was talking about with the screws.
Michael

GGaskill · « **Reply #7 on:** July 23, 2006, 09:46:03 AM »

OK, I looked at his mortar page. The screws are OK; the recoil force in a Coehorn tends to keep the parts together rather than force them apart, so the screws don't really play much of a role. But I think I would have brazed the parts together which would be a much stronger joint spread over a wider area.

Tigman · « **Reply #8 on:** July 23, 2006, 10:04:52 AM »

The breech plug has a small press fit if you do it right with not much of a step into the chamber. What if you made the step larger with a tight press fit to keep crap out from between the plug and chamber. And also machine the trunions flat against the barrel with a recess the same amount, so that there is more contact area for welding. He has drawn the trunions with a fish mouth to the outter contour of the barrel.

Thanks guys
Mark

GGaskill · « **Reply #9 on:** July 23, 2006, 12:20:51 PM »

I always cut a pocket in the barrel for the trunnions instead of contouring them to fit the barrel. Usually the barrel is tapered but the contour is not so the trunnions are not exactly parallel; they are perpendicular to the tapered surface instead.You can correct for this when maching but you still have a thin spot in the rimbase at the point where you get the most tension/compression from recoil. Using a pocket makes the rimbase much thicker at that point.

GGaskill · « **Reply #10 on:** July 24, 2006, 12:22:23 PM »

What if you made the step larger with a tight press fit to keep crap out from between the plug and chamber.

I would have to do the calculations to see if the chamber pressure would be enough to overcome the press/shrink fit pressure. The chamber pressure is going to tend to expand the barrel more than the plug. If the stresses were such that the joint never opened up, it would be OK with me.

Tigman · « **Reply #11 on:** July 24, 2006, 01:44:08 PM »

The breech plug is turned down to from a nipple in the center so you have 2" X 1" of weld then the casabell plate is welded onto that! The press would only be for keeping residue from between the parts!

Mark

GGaskill · « **Reply #12 on:** July 24, 2006, 02:01:33 PM »

I am more than satisfied with the fill weld that retains the breech plug.

accuratemike · « **Reply #13 on:** July 24, 2006, 02:55:01 PM »

Quote from: GGaskill on July 24, 2006, 12:22:23 PM

The chamber pressure is going to tend to expand the barrel more than the plug.

If it has a reduced powder chamber, with the barrel acting as an expansion chamber, wouldn't the chamber plug be expanding ? I'd bet it gets pretty darn tight when fired. The thing I'd be concerned with is, the thickness of chamber plug near the weld. I wouldn't count on the weld (or weld-penetrated plug material ) to have the same strength as the plug's steel. I suspect the image is simplified. It may not be accurate in this respect. I could be wrong. MIKE

Double D · « **Reply #14 on:** July 24, 2006, 05:24:54 PM »

It's been a long while since I built one of these and haven't seen my tooling in a long while, but I use to build these with a removeable Breech plug The casacabal and chamber were the breech plug. Acme threads, spanner to uncsrew the plug and a set screw in the botto to hold things. The face of the breech plug screw in ans beeded against a square fave in the barrel.

Cannoneer · « **Reply #15 on:** July 26, 2006, 09:07:19 AM »

Quote from: GGaskill on July 23, 2006, 09:07:50 AM

The prairie carriage was more or less a scaled down version of a field carriage.

Thanks for that info; I haven't seen a prairie carriage although I have heard of them.

There were four types of carriage that the mountain howitzers were mounted on, the 1st, 2nd and 3rd model prairie carriage and the pack carriage. I can't really see any differences between the 1st and 2nd models but the 3rd model seems a little more robust and it doesn't have an attached trail spike, instead it has two brackets on top of the trail, that are meant to hold the prolong. There are some good photos on the resource list. Jefferson Armory has pics of the 1st model ; click on mt. howitzers. Cannonsonline has pics of the 2nd, 3rd and pack carriages ; click on products. Theres an interesting photo on the Jackass Battery that shows the pieces hitched to single draft mules without the limbers. www.geocities.com/BourbonStreet/3946/jackass.htm I have a question ; first let me say that the closest I come to being a machinist is knowing how to use a file and a hacksaw. Many on the forum when discussing making the mt. howitzer talk about a breech plug or a plug that will form the rear radius of the powder chamber. Why is it so difficult to machine it out of solid stock? Is it because of the powder chamber?

Tigman · « **Reply #16 on:** July 26, 2006, 09:29:21 AM »

It is machined out of bar stock then pressed into the barrel. And welded. There's not much of a way to keep water and debis out from between it and the barrel.

Mark

GGaskill · « **Reply #17 on:** July 26, 2006, 09:58:13 AM »

Why is it so difficult to machine it out of solid stock?

Mainly because most home shop machinists don't have a lathe long enough to drill the bore, plus the tooling to do so would be quite expensive. You would start with a piece of 8" round a little over 3' long (and a little over 500 lbs.) and need to drill a 3.34" hole 30.9 inches deep and a 4.62" hole 25 inches deep.

Tigman · « **Reply #18 on:** July 26, 2006, 10:08:32 AM »

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Tigman · « **Reply #19 on:** July 26, 2006, 03:36:02 PM »

Which carriage do you guys think is best in terms of building? Most historical accurate? I really like the Pack carriage myself.

Mark

guardsgunner · « **Reply #20 on:** July 26, 2006, 03:54:13 PM »

Both carriages are correct. (Historicaly accturate). The prairie will barly fit between the slightly dented wheelwells of a Dakota pick-up. The pack carriage should have plenty of room. The prairie carriage has a wider stance, easier on rough ground. The pack carriage has less parts to build. The list goes on. I think the prairie carriage saw more use, at least through the civil war.
Your choice.

Cannoneer · « **Reply #21 on:** July 27, 2006, 01:59:23 AM »

Quote from: GGaskill on July 26, 2006, 09:58:13 AM

Mainly because most home shop machinists don't have a lathe long enough to drill the bore, plus the tooling to do so would be quite expensive.

Thanks for the answer.