Need Help!- It's laughing at me

[Robin Hewitt]

HELP I've had 4 goes at this and I'm getting nowhere

It's a metal cup pushed to the bottom of a cannon barrel and I'm going to get it out.

My expanding metal plug with Araldite just broke. Think I will have to cut it out somehow. But HOW? Lengthwise, radially, thread it? I have a CNC benchmill I can make tools.

It's tapered internally, around 3" diameter, 3.6" OD. It's been down there rusting for 93 years.

A tricky engineering problem because I can't get much closer then 44" from the muzzle end.

I am not used to failure

[jpgdesigns]

I like your idear of an expanding metal plug... I would just modify it alittle... I would use a piece of tubing that would fit over the all-thread to push the plug over the expander's taper, this would allow access to the "clamping" nut up but the muzzle. I would make two expanders one with a cutting tool, to cut a grove radially in the cup and one with a shoulder to fit in the grove cut by the other. I agree it would be a challenge... but that's what makes this fun!
I might even warm the barrel alittle and drop in a dry-ice plug to shrink the cup after the grove was cut...might help loosen the cup.

Good luck with it... let use know how it turns out

[Robin Hewitt]

Originally Posted by jpgdesigns I would make two expanders one with a cutting tool, to cut a grove radially in the cup and one with a shoulder to fit in the grove cut by the other.

Sounds like a plan, I could spring it into the wall and build in a depth stop

What do you think I should use for a cutter? It's ferrous because it rusts, but it hasn't pitted. Hard to say beyond that because it's 44" out of reach. It was applied shortly after the outbreak of WW1 when it became dangerous to sail the South China Seas.

A single point made from a file? A piece off a cutting disc? Could be a toad to realign if I need to change the cutter

[wwendorf]

How 'bout stickin' a bit o gunpowder down der' an lightin' that sucka off wid a fuze?

(of course i'm just kidding, but I couldn't resist the visual!!!)

Wade

[Robin Hewitt]

Originally Posted by wwendorf How 'bout stickin' a bit o gunpowder down der' an lightin' that sucka off wid a fuze? (of course i'm just kidding, but I couldn't resist the visual!!!)

No need to imagine what it would look like, have a piccy

You can see the wooden plug I put above coming out like a tracer bullet.

[wwendorf]

LMAO!!!!

My humor turned into reality! That's comical! (not to mention dangerous!!!)

Wade

[Robin Hewitt]

I never do anything dangerous or illegal with gunpowder. That's a 5" thick green oak block above it, the muzzle was chained, I was behind a brick wall.

BUT What about this here cutter? I am nearly ready to start CNC'ing the jig, if there are no better suggestions it's a piece of file blade.

A 90 degree cutting angle?

[jpgdesigns]

I was thinking a piece of high speed steel like a lathe tool you grind your self, and on the oppsite side of the cutter I would drill a few shallow holes to allow bearing balls held on the shallow holes by grease to provide less friction when turning the cutter and if you align the balls to the cutter tip they will help stabilize the cut once you get going...

oh the file will do just don't let it get too hot.

[lerman]

Turn a piece of 4x4 to fit the barrel. Drill a hole the length of the wooden plug. Then, using this as a guide, use a hole saw significantly less than the diameter of the barrel to cut a hole in the curved bottom of the metal plug.

You should now be able to put an expanding mandrel behind the plug. Inject some WD40 behind the plug and pull it out.

As an alternative (or in addition), make a planer type cutter and cut a lengthwise groove in the metal plug.

That's an interesting project. Please keep us informed.

Ken

[jerryjoeed]

Lerman has the right idea. Time and penetrating oil are your friends.
Is the plug bottomed against the breech?
How thick do you think the plug is?
The big wood bushing and shop made drill and tap extensions are a good start.
If you have the space behind the plug it will be easier.
If you have a pilot bearing or blind hole puller you could Knock 'er out
Or, drill and tap the center of the plug. Thread in the slide hammer and bang away.
Ya could also drill and pipe tap, thread in a fitting, and pump her full 'o lube to hydraulically remove the plug.
These are all old tried and true quick and dirty ham fisted monkey hammer tricks, nothing new. How well they work depends upon the specific stickyness of the situation and the monkey at the hammer.
There are more exotic ways of doing this but they are likely to turn into lots of work. Also, they can be used if the above fails miserably.

[DavidD]

I wonder if you could make a big clamping ring and clamp a steel block (that has a hydraulic port tapped into it) over the fuse location that would be 'hydraulic tight' and pump it from there.

If you cut a hole through the cup (to screw a hydraulic fitting in) wouldn't you cut into the fuse side of the chamber and not be able to build hydraulic pressure unless you sealed off the fuse hole?

Also, do you know anyone in the airplane maintenance business that could bring over a borescope and put it down the bore and look at the cup in detail?

Or maybe someone in the plumbing business with a sewer camera. I don't know how small a bore they can fit in though.

[lerman]

Try a webcam on a stick.

Ken