Author Topic: Reaming a barrel (Read 3473 times)

Evil Dog · « **on:** July 29, 2004, 01:44:00 PM »

Got my much awaited Grey-Star Cannon Technologies 1/3rd scale 6 Pounder barrel in today. After looking it over, I do have rather mixed feelings. The muzzle will have to be squared up, but that is something that I can do with handfiles and a goodly bit of time. What bothers me though is the steel liner used in the barrel. It appears to have a seam running lengthwize the entire length of the liner and although advertized as a 1" bore it seems to be more of a .950". Hopefully it won't be all that much trouble to ream it out to 1" and get rid of that seam at the same time. I may be overly optomistic, but was over at eBay looking at 1" reamers and found a couple that look like they may do the job. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=3829587581&ssPageName=STRK:MEBI:IT appears as though I should be able to mount it on a piece of 1/2" rod (or all thread) with a T-handle on the end and then ream the barrel by hand using a goodly amount of cutting oil. Is this the right idea, or should I look for a local machine shop that might be able to do it?

Double D · « **Reply #1 on:** July 29, 2004, 03:48:33 PM »

Hey Calamity you wanna tell him....You need a lathe.

I would inquire if that liner is seamless before I did a thing. It it's not seamless it should be sent back before you do a lick if work.

jj1 · « **Reply #2 on:** August 01, 2004, 07:49:54 AM »

hey evil dog, the 1/3 scale barrel that i got from greystar
was done the same way. the steel liner also has a seam.
the cast part seems plenty thick enough. it is a bitch having
to use odd size projectiles. :|

Evil Dog · « **Reply #3 on:** August 01, 2004, 09:50:52 AM »

Hi JJ..... could be worse, I heard from a couple of people where the barrel they got from Grey-Star had the liner off center at the breech end !!! At least mine seems centered on both ends.... determined by putting a long piece of 7/8" dowel down the bore and seeing if it appears to be pointed the same direction as the barrel. As to the ridge, although a lathe would definitely make things a lot easier, using an adjustable hand reamer it should be possible to get rid of that ridge without really screwing things up.

Double D · « **Reply #4 on:** August 01, 2004, 10:58:47 AM »

Gentlemen,

If the steel liner is a welded steel tube it is considered unsafe for use as a firing cannon barrel and should not be fired. The welding seam is subject to high pressure injection of blackpowder fouling into micro pores. this lead to corrosion and eventual rust pitting and rupture. Barrel liners in cannons must be seamless tubing

Casting a gun barrel around the steel liner leads to whole new set problems by themselves. The are a miltitude of problems with this method. I suggest you get a copy of the More Complete Cannoneer and read up on the dangers.

The proper way to line a cast Cannon barrel is bore the cast tube and insert a seamless tube with a properly designed breech plug in the barrel

I am going to post a warning with the listing for Grey star

jj1 · « **Reply #5 on:** August 01, 2004, 11:54:17 AM »

you know now that you mentioned it i think mine is slighty
off center at the breech end. i drilled the vent dead center.
if you shine a light down the vent and look down the barrel
the vent hole comes through off to one side. i would say mine is
about a 1/4 inch off.

Evil Dog · « **Reply #6 on:** August 01, 2004, 12:37:50 PM »

Perhaps that is why they are at the lower end of the price scale? Does fit my rather limited budget though.

Calamity Jane · « **Reply #7 on:** August 01, 2004, 01:28:42 PM »

Like Double D says, if'n it's got a seam, ya oughtta be gettin yer money back! Don't know why anybody'd try peddlin a barrel with welded-seam tube - maybe they'z crusin fer a law suit.

In any event, ya ain't goin from .950 to 1.000 by hand in one pass!

I reamed my liner with an adjustable hand reamer (before the breech plug waz installed) and the maximum I could turn on a 3/4 inch shaft with 24" handles waz about 0.003" per pass. An adjustable reamer wont werk fer ya 'cause they don't ream right to the end of the tool. You would need a whole set of reamers in about 0.005" increments from .950 to 1.000. But yer gonna want some windage to, so you'll need even more. I allowed 0.015" windage on my 1" bore.

BTW: After hand reaming fer a week, I gave up and motorized (moved to the lathe).

Find out what ya got fer a liner 'n' then decide what to do. Wouldn't wanna see ya blow yerself up.

Cat Whisperer · « **Reply #8 on:** August 01, 2004, 02:54:24 PM »

Quote from: Calamity Jane

Find out what ya got fer a liner 'n' then decide what to do. Wouldn't wanna see ya blow yerself up.

Good advice. When you light the fuse you want to KNOW whether it's a cannon or a bomb.

Spat · « **Reply #9 on:** September 12, 2004, 08:39:21 PM »

I was wondering, what if you made a cannon with welded tubing, but then had the bore hard chromed after reaming it. This should give you a nice smooth barrel for cleaning, and should present a barrier for the BP particles.

Another thing I was wondering about cannon construction was this:

Could you take a bunch of sections of thinner wall welded tubing, turn them such that each section had an ID slightly smaller than the OD of the next section, then heat it so that it expands and slide it on. It seems to be that if you managed to make sure that the seams didn't line up, and that the tolerances on the ID's and OD's were close enough you could end up with a pretty strong barrel.

My last question is...

Would the residual stresses introduced in this manner be beneficial or detrimental

You could always appropriately heat treat the entire assembly when your done to remove those stresses if necessary. You could also use different grades of steel for different layers, some stainless for the inside and outside, with cheaper carbon steel for the middle layers. You could even use a bit of seamless tubing for the innermost layer and use cheaper welded tubing for the rest as the 1/4 inch or so of seamless would certainly be a barrier to corrosive BP residue.

Cat Whisperer · « **Reply #10 on:** September 13, 2004, 12:55:17 AM »

Interesting thoughs on design comparisons. My approach as a builder takes into account the cost of MY labor and therefore my designs are much simpler - one piece of steel with a hole bored into it. No right or wrong method, just mine.

Double D · « **Reply #11 on:** September 13, 2004, 02:49:19 AM »

Welded seam tubing gan be every bit as strong as seamless. The issue with welded tubing isn't strength, it's microporosity.

Microscopic particles of black power are blasted into the micropores that are left from welding. Blackpowder fouling attracts moisture. Let black powder fouling sit and it acts like, and probably is very close to sulphuric acid.

Now think of that stuff in one of those micropores slowing corroding. A fresh batch of fouling blown in every shot. The micropore rotting and corroding and getting bigger and bigger. It quickly rots just like a cavity in a tooth. You don't even know you have a problem until the toothache or in the case of your cannon, a burst barrel.

Modern welding techniques are very good but you won't find the type of welded tubing being used in sleeving cannons to be guaranteed to be porosity free.

Stick with seamless tubing liners in cast barrels. (Yikes, thanks Bruce!)

Double D · « **Reply #12 on:** September 13, 2004, 04:21:51 AM »

Let me say that again so there is no mistake.

Stick with seamless tubing liners in cast barrels.

Cat Whisperer · « **Reply #13 on:** September 13, 2004, 06:49:40 AM »

Quote from: Double D

Let me say that again so there is not mistake.

Stick with seamless tubing liners in cast barrels.

Unless you WANT to make the national news.

Ya gotta be tough if you're stupid!

Fred · « **Reply #14 on:** September 13, 2004, 09:27:08 AM »

Well what about his idea of chroming the barrel?

What about using thinner seamless pipe then properly fitting it in a thicker walled seamed pipe

Will a pop can fit a 2 5/8 bore?

Should be shooting. FRED...........

Cat Whisperer · « **Reply #15 on:** September 13, 2004, 01:18:59 PM »

Fred - thanks for reasking the questions.

Chrome - good idea. Expensive to do the interior.

The aviatar on the left is my 4.5" which is Armaloy's version of industrial hard chrome. Makes cleanup a snap. Rinse, wipe and rinse. Done.

Bright chrome begins with a copper wash, nickle plating (buffed to a shine) and chromium over that for protection.

Industrial hard chrome may have a base on which to bond, no polishing and a heavier layer of chromium. VERY durable.

Haven't tried several layers of tubing. It would have to have a real advantage to go to all that trouble. Seamless is the simple answer.

2-5/8 = 2.625" diameter pop can = 2.595" that gives .030" clearance on the diameter. Add crud from firing, you get a little less clearance.
Should work, keep it clean.

Double D · « **Reply #16 on:** September 13, 2004, 05:46:03 PM »

Chrome bore is an interesting concept. iamb not sure the cost of hard chroming and seamless tubing would be that big of savings.

On the other hand if it was viable, I think it would be an industry standard already. it's not.

That applies to double lining as well.

I can just imagine the problems with shrink fitting a seamless tube inside a seamed tube inside a cast barrel. If you did a slip fit and epoxy as most are now done, the inner seamless liner would still have to be minimum 3/8 standard. If you use a thinner tube there is to much chance you will get a bulge in the chamber from firing. The inner liner will expand to fill that thousandths or two gap between the inner seamless tube and outer seamed tube. The effort is isn't worth the time. Do it right from the get go. Again if it was a viable alternative it would already be done and it is not.