Tube ID end shrinking?

[Tr0nd]

I was not ot sure what to call this thread.

What I have is a 4mm od tube, with a 2mm id, I need the inner diameter at the last 5-6mm of the end of the tube down to 1mm, and I wonder if there is some tool that would do that, I imagine something with 3 wheels with some pressure and a bit of heat could do it? But where to find something like that?

 

[RJSakowski]

The tool you are looking for is called a swage. What is your tube made of?

 

[Tr0nd]

That was fast

The stuff I have is stainless, it's going to be nozzle on a engine piston sprayer. If the end is to big I lose too much pressure.

 

[RJSakowski]

Stainless will be difficult. Were it copper, it could be annealed prior to the rather substantial required deformation. A better approach might be to make an insert with the matching o.d. and your 1mm i.d. and press it in.

 

[Chewy]

That small of diameter and short distance, I don't think you will find any tool that could be modified. The first option is to drill a series of smaller holes in a piece of steel. Insert a 1mm drill rod stub in the center of each hole. Heat and drive the piece in until you get what you want. The second way which I would try is to drill the hole with the drill rod. Put you tubing in a tiny 3 jaw lathe chuck and slowly squeeze and rotate until you think it is close. Then drive the tubing down on the drill rod to resize out. Lacking that you could just re-drill the hole. If that doesn't work, going with the insert as RJSakowski said or just a whole new piece out of solid stainless. You talking a little chunk of steel less then 1/4 inch, so it shouldn't be to hard to find a piece of scrap.

 

[Chewy]

Just wondering. Could you make up an insert to slide inside the tube and then hammer the end over. On an angle or almost flat. Then drill correct size hole?

 

[extropic]

Here is a concept that might help you find/make a swaging tool.
Of course, you'll probably want smooth rollers rather than knurls.

Three Wheel Knurling Tools

 

[Jimsehr]

One piece I would weld end then drill to size.

More pieces I would look for a thread rolling company.

 

[ChazzC]

If it’s for a sprayer, you’re going to want a smooth transition, so swaging was a good thought. How about start with a 4mm x 1mm tube and drilling out one end to 2mm to match the tube you have?

 

[Tr0nd]

Thanks for all your replies, really helps, so I tested a few things and the pressure route didn't really go well, so I ended up threading the end for a 3mm bolt. I have fastened it with loctite, when it cures I'll try chop the end and drill a hole in it. And hope it stays there.