Author Topic: A SAMCC barrel (Read 2110 times)

mrrattle · « **on:** December 07, 2009, 06:21:57 PM »

heres my samcc barrel, just finished polishing
all done on a 7x12 chinese lathe
carriage comes later this week, i like oak, but think i might use cherry wood instead
still gotta ream my bore too, is at .505 right now
then i gotta drill my trunion pockets-have mini mill for that operation, indexing no problem

but i could use some guidance for trunnion pockets,
how deep did you bore your trunion pockets?
did you just press fit them?

Double D · « **Reply #1 on:** December 07, 2009, 06:47:22 PM »

Welcome to the board MrRattle. I split your post out of the other thread. That thread is about the new South African Miniature Cannon Club cannon being made and sold by Board sponsor Brooks USA..

Since yours is a personal build we'll pull it out!

Good choice for a first build. I don't think you will be disappointed The original SAMCC gun has a muzzle swell that is the same diameter as the cascabal for aiming purposes. The Brooks SAAMCC gun has a more tradition cannon shaped muzzle swell.

Can you share some pictures of the modification you made?

Cherry, oak doesn't matter, can't be seen under the paint any way.

mrrattle · « **Reply #2 on:** December 07, 2009, 06:52:03 PM »

I will post more pictures as soon as i take some better ones

or should i say, once i get it off the lathe and cut off the tail i used for turning

really do need some guidance with the trunnion pockets though?

any info on depth or how close to bore wall one can mill in?
thanks in advance.

Double D · « **Reply #3 on:** December 07, 2009, 07:07:55 PM »

The ones on the Brooks gun appear to be pressed. The ones I did on the guns I built are threaded and welded.

Here's a diagram from the drawing for my Parrot gun. This should give you an idea how to go about it..

mrrattle · « **Reply #4 on:** December 07, 2009, 07:33:31 PM »

is there any general rule one should follow when determining trunion pocket depth?

say for any given bore size there should be x thousands of material between bore and pocket bottom.

or would it be safe to say that if one was to mill a flat bottomed pocket (in brass), then press in a flat ended
trunnion until it bottomed, then sweat in some silver solder or even brass that it would be safe to
mill to with a couple thousands of the bore wall.

I like your system of threading the the trunnion in, but this once again brings us closer to the bore wall.

in my case i have .545 inch of material between the bore wall and the outside edge of barrel,
i am thinking i might just mill in .250, press in a trunion and call it a day,

GGaskill · « **Reply #5 on:** December 07, 2009, 09:07:28 PM »

I like to leave about half of the wall thickness at the point of the trunnions. The barrel diameter at the front of the trunnions is 1.666" so if you are using the specified .516" bore, the wall thickness is .572" so the pocket depth could be .286".

Since brass doesn't deal with high heat as well as mild steel, I would get some high strength solder (but not regular silver solder as that requires a lot of heat) and solder the trunnions to the barrel. If you leave only a few thousandths clearance for the solder, it will actually form an alloy with the copper that is much stronger than plain solder.

seacoastartillery · « **Reply #6 on:** December 07, 2009, 09:46:13 PM »

Quote from: mrrattle on December 07, 2009, 07:33:31 PM

is there any general rule one should follow when determining trunion pocket depth? There is no such thing.

say for any given bore size there should be x thousands of material between bore and pocket bottom. Ditto.

or would it be safe to say that if one was to mill a flat bottomed pocket (in brass), then press in a flat ended
trunnion until it bottomed, then sweat in some silver solder or even brass that it would be safe to
mill to with a couple thousands of the bore wall. No, it would NOT be safe.

I like your system of threading the the trunnion in, but this once again brings us closer to the bore wall. Your wall thickness needs to be more to do this.

In my case i have .545 inch of material between the bore wall and the outside edge of barrel,
i am thinking i might just mill in .250, press in a trunnion and call it a day.

   BINGO! You just figured it out yourself and we would use the same depth of hole and remaining wall thickness for one Very Important Reasonwhich is that the pressure curve of a blackpowder cannon peaks very quickly and drops off noticeably soon after it's peak, so the wall at the trunnion is only subjected to a relatively small fraction of the peak pressure.

   It is wise to start with very light loads and work up to your most accurate load which, in cannons with relatively short tubes, is almost Never a maximum load. Good advice for the new owner too, as I remember that this is a gift. For the guys that don't have a mill or center-cutting end mills, remember an old gunsmith trick: Drill the hole so the depth is short by an amount equal to the length of your drill point, then continue drilling a flat bottom hole with a drill bit of the same diameter which has had it's point removed by grinding. Drill lightly to the proper depth by removing all of the drill point shape at the bottom of your hole, then Stop. Take care in locating your trunnion holes and drilling them square to the bore axis and co-axial to each other.

   Mrrattle, It looks like a good plan, so far. Good luck!

Mike and Tracy

We like your choice of a small lathe too. Here is our Metalworker Variable Speed Lathe we use to make hundreds of pins, rivets, small shafts, screws, small bolts AND Elevating Screws such as you see here.

GGaskill · « **Reply #7 on:** December 08, 2009, 02:05:59 PM »

Another alternative that might work would be to drill through the trunnion and counterbore for an Allen head bolt and tap the barrel without cutting any pockets. You would have to properly contour the underside of the trunnions to match the outside of the barrel which would be a challenge since the barrel is tapered. You still would be best served to solder or braze the trunnions in addition to the bolts.

I still think the pockets and high strength solder is better.

dan610324 · « **Reply #8 on:** December 08, 2009, 10:28:52 PM »

I got another idea that I have N O T tested ,
but its just for cannons with below center mounted trunnions.

drill or mill a hole all the way through the barrel , 1/10 mm larger then the trunnion "axle"
silver solder the axle in place before the bore is drilled

then when the bore is drilled half the diameter of the trunnion axle would still be remaining

this is just a teoretical idea so far , what do you guys think about it ??

Victor3 · « **Reply #9 on:** December 08, 2009, 11:01:00 PM »

I don't see any problem with that. The silver solder is going to seal any gap between the two pieces. As an alternative, you could shrink-fit the bar into the barrel and forget the solder.

If you had a trunnion bar larger in diameter than the bore, you could even put it on center.

Double D · « **Reply #10 on:** December 09, 2009, 03:04:33 AM »

The Trunnion on the original South African Miniature Cannon Club Cannon wa below centerline. It was made by drill a hol through the barrel below bore line and inserting a steel pin. Brass false trunnion were slide on the pins. I suspect the false trunnions were pressed on the steel pins.

mrrattle · « **Reply #11 on:** December 19, 2009, 04:08:10 PM »

the gun is finished. sorry no powder can in the picture-dont have one just now.
she came out a bit muzzle heavy but not too bad. have not yet fired the gun,
will do that sometime over christmas.

i made the muzzle flare a bit smaller than the plan and the flare is more gentle radius
i made the carriage a 1/2 inch shorter than plans called for. i also made brass wheels instead of wood.
notice how i made brass retainers cut out of brass sheet then screwed to end of axle (did this purely because i prefer the look)

and a before/after pic, looks like I have enough left for one more gun.
this cannon build started purely because i was at a scrap yard and found a chunk of brass laying about.

RocklockI · « **Reply #12 on:** December 19, 2009, 04:27:41 PM »

Thats very very nice

VERY nice

Gary

Double D · « **Reply #13 on:** December 19, 2009, 04:36:36 PM »

The original South African Miniature Cannon Club cannon is also muzzle heavy. The Muzzle swell of the gun was removed and replaced with a larger swell that matched the diameter of the rear cascabel. This made it easier to aim the gun.

In order to deal with the nose heavy problem some wrapped rubber bands around the gun.

This worked for a while until the bands broke. Changing bands also changed the aim pot. I fixed the problem long term witha some bungee cord.

If you have the capabilities you might want to save your pictures for posting on board a 72 DPI. They won't use as much band width and load faster on the board. The guys visiting here on dial up will like it a lot better also!

mrrattle · « **Reply #14 on:** December 19, 2009, 05:24:17 PM »

Images resized. Thanks for pointing that out.

I should remind myself to read the forum rules before proceeding.
One very easily gets complacent and makes assumptions that are usually wrong.

and i find myself making more and more assumptions as i age.

Double D · « **Reply #15 on:** December 19, 2009, 06:30:59 PM »

For most computers on the internet any thing more than 72 dpi serves no usefull purpose. Using a higher resolution just slows things down and a lot of people with will treat them like links and just ignore them and move on before they load. We don't have a rule about it, just suggest you do it to make your visit more enjoyable to others.

As to the powder can. That's not a requirement either. Some years back one of the old timers here suggest that when you post a picture here that you include something in your pictures to show scale. He suggested a powder can.

Kind of hard to tell how big the SAMCC cannon is in my picture above. But this picutre gives a better idea.

You turned out a pretty nice cannon and we will definitely be watching for your next project. Have you looked at the sticky at the top the board called safe loads and cannon plans for your next project for that other piece of brass?

Ex 49'er · « **Reply #16 on:** December 19, 2009, 08:04:17 PM »

DD, Is that trench art shell the club trophy from SAMCC? Field Artillery ...something? Good looking shell.

Josco · « **Reply #17 on:** December 20, 2009, 07:25:28 AM »

Nice job on the barrel and carriage. One question. How did you drill the bore? Obviously not in that lathe.

mrrattle · « **Reply #18 on:** December 20, 2009, 08:39:13 AM »

thats where you would be wrong, I did the boring on the little 7x12 lathe.
i should have taken some pictures, but it goes like this.

gut your tail stock, then make a piece that just slides into the bore, mine was .872 inch
now you drill a 1/2 inch hole into the bushing
this now becomes a guide for later operations

you will need a 1/2 inch end mill (or whatever bore your going to) and a piece of drill rod the same size
you will weld the end mill to the end of the drill rod (lay end to end in piece of angle iron and clamp in place), you need this to be straight and you also need to grind the weld down smooth or slightly undersize.

now you need to put your barrel on the lathe with a 4 jaw chuck and a steady support
first you drill and bore as deep as you can using traditional methods.
now the trick to make it work is the bushing(s) i made for the tailstock to use as guides

i finished the bore in two steps

first drilled using a 1 foot long 3/8 drill bit, i made a bushing for this in the tailstock as well, i had the drill bit mounted in a electric drill that i used to advance the by hand. once i was to depth i bored 2.96 inches deep with a boring bar (thats as far as i could reach)

the bored hole is just .0015 larger than the end mill. the bored hole now works as a near perfect guide for the end mill. swap the bushings in your tailstock and once again use hand drill to advance the mill end. The lathe was also running. no cooling oil was used-it would just make the chips pile up and bind. took about 4 hours to bore out, then another half hour ream.

came out so close you cant even see any offset in dowel to barrel.

I am considering making a bore sight-i have a bunch of lasers and precision aiming devices for my telescopes, shouldn't be too hard to make a bore scope for the cannon.

Double D · « **Reply #19 on:** December 20, 2009, 08:58:32 AM »

Please do post picturee of the bushing set up for the tail stock. I think I under stand it. You remove the tail stock quill and the bushing replaces the quill, is that correct?

mrrattle · « **Reply #20 on:** December 20, 2009, 09:25:52 AM »

yes, remove quill, insert bushing you make then drill to hearts content.
just take it easy or you will go off centre
run both the drill and the lathe, between the 2 i had about 600 rpm total.

Josco · « **Reply #21 on:** December 20, 2009, 09:49:04 AM »

Thank you for the explanation and pictures, very clever!
How long is the barrel and what's the distance between centers on your lathe?

Thanks
Joe

mrrattle · « **Reply #22 on:** December 20, 2009, 09:58:52 AM »

barrel is built from the samcc plans on this site

barrel is 10.89 inches long, bore depth is 9.250 inches

lathe is 7 x 12

i dont think i could make anything longer than this barrel unless i get a bigger lathe.

Josco · « **Reply #23 on:** December 20, 2009, 10:30:57 AM »

Mine is a 9" S.B. with a 42" bed and approx. 24" between centers It's just about maxed out doing a 10" barrel using the tailstock with Jacobs Drill chuck and 12" drills and reamers. Here's a few pics. of my barrel, I'll finish the carriage this winter.

mrrattle · « **Reply #24 on:** December 20, 2009, 10:52:38 AM »

I am now officially jealous.

really i wouldnt know what to do with all that extra working space.

nice barrel too!

405winchester · « **Reply #25 on:** January 03, 2010, 04:16:03 AM »

Well its time for me to get a piece of brass and get turning!!!
Just picked this up yesterday, Traded a pistol that i bought for $120 used and used for 5 years, and the lathe was turned on and never used