spin forming

Sounds like you're making push rods. Considering the alloy, I think this is a forging job rather than spinning. How long is the tube and is it straight with the other end open? Is the closure to be air tight? If so, what is the test pressure requirement? How many pieces does the job involve?

Spin form can be used to seal like a forge or weld. Same process as spin welding. Friction to heat then pressure to form/close. Is this what you are referring to?

If simply closing the tube you could use different methods such as ram forming, progressive forming, etc. Depends on the final shape you are looking for.

There are standard end forming machines and tooling available.

Need a little more information. Length of tube, tolerance required, finished form, etc.

I need to close the end of a 8 in tube.

It needs to be airtight. It will be boron coated and used as a thermocouple seath in molten aluminum to control the temperature of a small open crucible R and D bath.

Sounds like you only need one. And for R&D. I would simply crimp the end. (squish it flat) like in A/C units.

I'll buy that!

We already made some that I hammered flat. I could not crimp them shut in the vise because they are too thick. But we would like them to be more "professional" looking.

So I would like to round the end shut like a test tube.

We have a drill press..Can I use a V block and spin it into the V block and form it?

I want to make about 20 of these and 20 with a slightly thinner wall: Carbon Steel 1/4"OD .18" ID .035" wall

Might work if you heat the end you wish to form to it's plastic state. You might have to weld the end if you wind up with a small hole. If you try it, I'd like to know the results. I love ingenuity.

Keep the speed up on the drill to maintain your heat on the part. The v-block will act as a heat sink.

Don't bother with lube.

Preheat (as mentioned).

You can use a die penetrant to test for leaks before air testing. Makes any leak easier to see. Your plating may seal any pinholes as well.

Watch that you don't weld the tube to your forming block.

Good luck!!!!

Would GTAW/laser/EB welding some sort of closure work?

a machined or stamped plug could be butt welded.

Any type of forming to close end will thicken that section.