Author Topic: shrink fit metal tubing  (Read 1313 times)

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Offline bert-nc

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shrink fit metal tubing
« on: September 13, 2009, 02:12:39 PM »
with very limited metal working equipment I have decided to shrink fit a plug (1 3/4 round 1018 bar) into a  dom metal tube. Do I need to heat the tube and cool the plug, or will heating the tube be sufficient? Trying to make a golf ball mortar.

all comments and suggestions appreciated

bert-nc

Offline Cat Whisperer

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Re: shrink fit metal tubing
« Reply #1 on: September 13, 2009, 02:16:12 PM »
Bert -

WELCOME to the board!

What caliber is it now?
Tim K                 www.GBOCANNONS.COM
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Offline cannonmn

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Re: shrink fit metal tubing
« Reply #2 on: September 13, 2009, 02:51:03 PM »
You lost me on why it needs a plug?

Offline Double D

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Re: shrink fit metal tubing
« Reply #3 on: September 13, 2009, 02:51:48 PM »
High Bert-NC  and welcome.

You might give us a few more details about what you are making  an some dimensions of the material you are working with.

Offline KABAR2

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Re: shrink fit metal tubing
« Reply #4 on: September 13, 2009, 02:59:56 PM »
You lost me on why it needs a plug?

I think he is using Drawn over a mandrel tubing and wants to breech it by shrinking a plug in place,

he should look at our stickies for wall thickness before considering this, also he did not mention whether

or not it would have a chamber in the breeching, or any sort of welding....... need lots more info.......
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Offline bert-nc

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Re: shrink fit metal tubing
« Reply #5 on: September 13, 2009, 03:23:43 PM »
working on more details---

will post a better description monday afternoon

bert-nc

thanks for the welcome

have been reading for a while as a guest

Offline GGaskill

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Re: shrink fit metal tubing
« Reply #6 on: September 13, 2009, 05:02:32 PM »
Steel expands about 6 millionths of an inch per inch thickness per degree Fahrenheit.  So whether you need to heat one and shrink the other depends on the dimensions of the two parts and how hot and cold you can get things.
GG
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Offline bert-nc

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Re: shrink fit metal tubing
« Reply #7 on: September 14, 2009, 01:21:47 PM »
Steel expands about 6 millionths of an inch per inch thickness per degree Fahrenheit.  So whether you need to heat one and shrink the other depends on the dimensions of the two parts and how hot and cold you can get things.

thanks,
that was what I needed to know

bert-nc

Offline bert-nc

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Re: shrink fit metal tubing
« Reply #8 on: September 14, 2009, 01:28:06 PM »
 

some details about the  mortar that I am building.
3 inch outside diameter barrel, 1.75 inch bore, 7 inches long, .625 inch wall
powder chamber is 1 inch diameter x 1.75 inch deep
total wall around powder chamber is 1 inch thick
all but ready to place the powder chamber into the barrel by shrink fittiing.
I believe I will heat the barrel to do this.
Tried to include a rough drawing but for some reason it did not show up.
welcome all questions or concerns

bert-nc

Offline GGaskill

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Re: shrink fit metal tubing
« Reply #9 on: September 14, 2009, 02:47:23 PM »
You don't say whether the inside of the tubing will be machined to fit the plug.  It should be unless the hole is accurately circular within a couple of thousandths.  The thick tube will not distort enough to fill in voids due to non-circularity of the tube.
GG
“If you're not a liberal at 20, you have no heart; if you're not a conservative at 40, you have no brain.”
--Winston Churchill