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Do machinists do this?

Next time put a 3/8 rod in the drill chuck on your tailstock, insert it into the pipe as deep as the part. It will keep it from flying away should it come loose.

I've also had great luck cutting inside out when holding sketchy shit. Does that/should that matter ? No. In my mind it does, maybe a superstition. lol Who knows
 
other than grabbing from the ID

you guys thing there are teeth on both ends of the jaw for a reason?
I have done this many times
 
WaterH said:
It’s at least 1/4” wall. Pretty strong.



My lathe has a steady rest. It’s not on in the pic.



The end I started with was sawn off with my bandsaw. I guess I could have squared it bett
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Just an up date. I was welding a cap on one end of this and I decided to put it back on the lathe to clean up the weld. I chucked it on the ID with one of the 1/2” steps. The MF’er came flying out. Also, the tube was too small to flip the jaws and get the whole jaw in the ID.

Now I feel like I made the right choice. (Actually, the right choice is to make some jaws, but almost right)
 
WaterH said:
Just an up date. I was welding a cap on one end of this and I decided to put it back on the lathe to clean up the weld. I chucked it on the ID with one of the 1/2” steps. The MF’er came flying out. Also, the tube was too small to flip the jaws and get the whole jaw in the ID.

Now I feel like I made the right choice. (Actually, the right choice is to make some jaws, but almost right)
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Once you have it capped, you can use a live center with a piece of scrap to hold it against the chuck with the tailstock:homer:
 
WaterH said:
Just an up date. I was welding a cap on one end of this and I decided to put it back on the lathe to clean up the weld. I chucked it on the ID with one of the 1/2” steps. The MF’er came flying out. Also, the tube was too small to flip the jaws and get the whole jaw in the ID.
Click to expand...

Every wreck I have had with aluminum was from getting greedy with my cut
 
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Firstram said:
Once you have it capped, you can use a live center with a piece of scrap to hold it against the chuck with the tailstock:homer:
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Yes, I should have done that, but I had pipe threads in the center hole. I didn’t want to mess them up. Of course in hind sight, rerunning a tap in there is way easier then polishing big scratches and gouges out. Lol. (Not to mention, scaring the shit out of me)
 
How about a picture of the welded part you were trying to chuck up so we can help with that part too.
 
WaterH said:
Yes, I should have done that, but I had pipe threads in the center hole. I didn’t want to mess them up. Of course in hind sight, rerunning a tap in there is way easier then polishing big scratches and gouges out. Lol. (Not to mention, scaring the shit out of me)
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When there's pipe threads in the end you use a pipe plug and center drill that after truing it up. Be careful!!
 
WaterH said:
Oh sure, you’re just looking for material for the “shiddy weld” thread.
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I got the pipe to pipe cap but then you’re saying pipe threads so that’s the confusing part. Blur out the shiddy weld if you want…we will assume it is anyway😄
 
Brad said:
I got the pipe to pipe cap but then you’re saying pipe threads so that’s the confusing part. Blur out the shiddy weld if you want…we will assume it is anyway😄
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It’s just a flat disc welded on the end of the tube. I cut the disc out of flat 1/4” sheet. To make it perfect round, I drilled a 3/8” hole and spun it on the lathe. (With a mandrill) After welding, I wanted to check if it would hold water, so I taped the hole for pipe thread to plug for the water. This hole will be used later also. I’ll get a pic.
 
Brad said:
I got the pipe to pipe cap but then you’re saying pipe threads so that’s the confusing part. Blur out the shiddy weld if you want…we will assume it is anyway😄
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675363E2-9C78-4855-A559-17432A9371AC.jpeg
 
Brad said:
Good thing you blurred out the shiddy weld
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Yea, I admit defeat. I can’t weld aluminum to save my life. I believe my tig is to blame. That’s my story anyways. The weld won’t hold water. The thing is, I machined it almost perfect. I pounded the disc in and it almost he’d water without welding. Lol. I only need one end to hold water, so I’m getting a pro to weld the other end. I also made this cap with an o-ring that fits nice. I’ll get the pro to weld that neck in also.

9EFC69F6-DDD1-4182-92F5-536A0A10837D.jpeg
 
WaterH said:

Do machinists do this?​

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As more and more years go by for me, I have come to the realization that any given "pro" is probably going to do all kinds of sketchy stuff to get the job done and get their boss off their back. :laughing:

That said, take a step back and figure out how things might go wrong and do what you can to minimize those things. 😉 If you acknowledge the reality of these issues and do your best to make sure you're not going to kill yourself (or the proverbial busload of nuns and orphans) or destroy your tools, equipment, or shop - go for it.
 
bgaidan said:
Thread a pipe nipple in to that tapped hole and stick your live center in that. Use something like a CNMG insert to gouge/vee-groove your weld so your pro can fix it.
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Not sure if it can be fixed. I think impurities have made pin holes that are not on the joint. So if you reweld the joint, you still don’t get em. I guess if I V’d it out big enough. In any case, the top will have a vent and doesn’t matter if it leaks.
 
CarterKraft said:
The end of the unsupported tube is the sin not the jaws.

It's thin-ish tube, you can't clamp it for shit regardless so jaw engagement is pretty irrelevant.
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It wouldn't take long to make some kind of stiff star or disc insert for the inside of the tube to rest against, while being clamped by the outside jaws.
I believe that's what a real machinst would have done. Anyway OP, try to not kill yourself, you have entertainment value :flipoff2:
 
denis said:
It wouldn't take long to make some kind of stiff star or disc insert for the inside of the tube to rest against, while being clamped by the outside jaws.
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Very common to make slugs that fit the ID tight with thin wall tube, wood is cheap or aluminum.
Also common to make a wood slug for the end in the wind that is set 1/4-1/2" deep (whatever you need to get the tooling to fit) with a little super glue, use the live center and true up the end.
 
Every time I had a spectacular wreck it was doing something like this with a piece of tubing.
I still think there is a 4" piece of 2-3/8 tubing under my lathe that was ejected from trying to turn face out on the end.
 
CarterKraft said:
Every time I had a spectacular wreck it was doing something like this with a piece of tubing.
I still think there is a 4" piece of 2-3/8 tubing under my lathe that was ejected from trying to turn face out on the end.
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Yes, that and turning a disc on too small of a mandrill. My lathe is so heavy duty, that I don’t really have to worry about breaking it. So if I stay clear of shit flying, I’m only wrecking the piece. Nice to have enough material to do another on hand.
 
WaterH said:
Yes, that and turning a disc on too small of a mandrill. My lathe is so heavy duty, that I don’t really have to worry about breaking it. So if I stay clear of shit flying, I’m only wrecking the piece. Nice to have enough material to do another on hand.
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One of my biggest wrecks was turning a V belt groove into a air compressor pulley. It barely fit in between the ways and I was turning it on a mandrel but I didn't think about cutting the right side v belt groove would pull it off the mandrel, at what I learned later was "Way too fast" speed:lmao:
 
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