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Returning To Basics Is Valuable… Slip Fits… Simple, Cool, Useful

Often if you are working with tubing or pipe you need to link them together with other tubes or pipes. Besides welding or clamping, knowledge of tube end forming can make this go a lot better.

The most common type of connection between a couple of pipes achieved through end forming would be a relatively simple slip fit, where the end of one pipe is modified to fit inside or outside another. This may be done in conjunction with welding or clamping, but you can easily imagine how robust a connection can be formed in this way.

Reduction Slip fits: If you are fabricating a structural member that is going to be visible or out in the open, you would want one tube to slide inside the other in a way that the outer tube is the same diameter as the rest of the tube, making your slip fit as invisible as possible. This is easy to accomplish, but you need to use a swager box, found on our benders and our 1673 model expander/swager. You clamp the tube, and use the cylinder to drive a reducer die over the end of the tube to make the outside diameter slightly less than the inside diameter of the outer tube.

Expansion slip fits: If you are working with the flow of liquids or gases, you may want the inner surface to be as smooth as possible, so you would be better served expanding the outer tube to fit over the inner tube. It is also likely that you would want the inner tube to be pouring the liquid or gas into the expanded outer tube to eliminate any leakage.

Expansions can generally be achieved in one of two ways… Most commonly, with segmented expander tooling (possible with all Huth expander, swager or bender models), the tool is inserted into the end of the tube or pipe. An arbor is drawn back to spread the segment fingers, which in turn expands the tube.

The second way, which purists love because you achieve a perfectly round expanded tube, is to expand with a swage die in a swage box… again, clamping the tube in place before driving the swage die into the tube or pipe to achieve the desired expansion.

If you have worked with us in the past, you probably could have written a far better explanation of this. But every so often, returning to basics can be valuable. Please call us at 800-558-7808 to share your end forming ideas.

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