Shop Press? How does it do that?!

[nateman_doo]

How do shop presses work? Lets say for instance, I wanted to press fit a sweat cap over a pipe? how would it clamp and put pressure 360° around it?
(yes I know it would be soldered/brazed/sweated-Just looking for theory)

[cornbinder23]

Well, if we are talking about copper here ,caps would be slip fit. So, why would you need a shop press? The caps or couplers or fittings should just slide on.
I only really use mine for separating bearing assemblies, swedging, flairing, seating bearings, broaching etc...

Is there more to the question?

JTCUSTOMS

[nateman_doo]

I have a section of 2" solid rod of copper, that I want to press into a 2" ID copper pipe. I don't wish to braze it because that thing takes lots of heat (and I only have a single propane torch). It has to clamp the pipe and be watertight.

I am not looking for alternate means, just looking into the process of how a shop press can work to seal the "plug" into the pipe.

[eartaker]

nateman_doo,

A press simply uses a great amount of pressure to push 2 pieces together. The seal will be determined by how much pressure is needed to force the 2 parts together and how round they both are. If you rod is 2" in dia and your pipe is 2" OD this will not work. but if the pipe is 2"ID you should have a firm fit.

[pp7]

I have a section of 2" solid rod of copper, that I want to press into a 2" ID copper pipe. I don't wish to braze it because that thing takes lots of heat (and I only have a single propane torch). It has to clamp the pipe and be watertight.

I am not looking for alternate means, just looking into the process of how a shop press can work to seal the "plug" into the pipe.

I apologize for offering "alternative means."
If you want them to seal tightly, I would suggest another way. You can put the rod on a lathe and trim to exactly 2.000 inch. Put the pipe on a lathe and bore the inner diameter to 1.995 inch. This will create 5 thousandths overlap. Place the rod in a freezer for 10 minutes. Place the pipe in an oven to 300 degrees for a few minutes. The difference in temperature will create about 6 to 7 thousandths difference. Fit the pieces QUICKLY together, before the temperatures equalize.

[H.A.S.]

I have a section of 2" solid rod of copper, that I want to press into a 2" ID copper pipe. I don't wish to braze it because that thing takes lots of heat (and I only have a single propane torch). It has to clamp the pipe and be watertight.

I am not looking for alternate means, just looking into the process of how a shop press can work to seal the "plug" into the pipe.

Sounds like you may be looking for an interference fit:

Here's some basic info:

http://www.engineersedge.com/bearing..._press_fit.htm

There are other sites for dimensions, using different materials, etc.>

[nateman_doo]

I apologize for offering "alternative means."
If you want them to seal tightly, I would suggest another way. You can put the rod on a lathe and trim to exactly 2.000 inch. Put the pipe on a lathe and bore the inner diameter to 1.995 inch. This will create 5 thousandths overlap. Place the rod in a freezer for 10 minutes. Place the pipe in an oven to 300 degrees for a few minutes. The difference in temperature will create about 6 to 7 thousandths difference. Fit the pieces QUICKLY together, before the temperatures equalize.

No need to apologize. That sounds interesting, but I don't think I could get the tolerances that close on my Harbor Freight 7x10 lathe. I was thinking of making a steel jig like so:

And making the hole just a thousandth smaller then 2" so that when it clamps all the way around it should compress the pipe on the solid core. At least thats my theory.

[Pro-Fab]

It looks like you are wanting to CRIMP the pipe, which means you presently have a slip fit.
To create a press fit, you would force the rod into the pipe if the inside dia. of the pipe is undersize. To press it in dry would cause galling, and would not seal.
To CRIMP the pipe with your steel jig you won't get a watertight seal either, unless you are able to insert an o-ring, silicone, or other collapsable membrane first, and just use your crimp as a lock so that pressure cannot blow them apart.
Make sure that your jig fits close around your pipe, and create a lobe on each half that can bite into the softer copper. It will work even better if you grind or machine small cavities on the rod at the same position. Just press down with your crimper, rotate it 90 deg. and repeat.
You didn't mention the length of the fit. If you have room, you can repeat the process farther down the pipe, but like I said, the crushing force will not give a water tight seal if there is any pressure what so ever.
Good Luck!

[nateman_doo]

Can you elaborate a bit more? There will be nothing but atmospheric pressure. maybe the volume of a cup of water at the most behind the seal.

I saw this picture and I was curious how the process worked:

[Fastest1]

You should be able to get the tolerances to achieve a watertight seal easily with your lathe. Put 1 in the oven and the other in the freezer, they will go together and once back to ambient temperature, you wont get them apart nor will they leak.

No need to apologize. That sounds interesting, but I don't think I could get the tolerances that close on my Harbor Freight 7x10 lathe. I was thinking of making a steel jig like so:

And making the hole just a thousandth smaller then 2" so that when it clamps all the way around it should compress the pipe on the solid core. At least thats my theory.

[nateman_doo]

nothing will crack when exposing cold metal to very hot metal?

[pp7]

nothing will crack when exposing cold metal to very hot metal?

I placed (frozen) bearing races my my custom wheel hub (heated to boiling temp) recently. Nothing cracked. You only get one try, though. Once the temperatures equalize, the parts are mated permanently.