How would you fixture this?

[Jim Timber]

14 gauge 1.25" round tube "T" with a stub leg fish-mouthed onto the long leg. The two horizontal sections need to be parallel within a couple degrees, but it's not mission critical.

Would you make a "V" base to lay the three sections into which allowed access to the joints from both sides, or would you just put it all on a flat plate with some location tabs to hold things enough to tack it and then remove from the fixture to finish?

I have 100 of these to do and would like to MIG them after TIG tacking (if needed). When I did production MIG welding, we always made better time the more of the part that could be welded in the fixture. Fixtures were often hinged to get to the back. Those were more involved assemblies though. Once these are tacked, they can be finished in a vise with ease.

How would you do it?

 

[Shield Arc]

With that many to build. I would make a fixture out of angle iron, with the toes up, tacked to a flat plate.

 

[Jim Timber]

The top of the T is also fish-mouthed too. I should've clarified that.

Would you make it so the whole joint could be welded in the fixture or just to tack it and then finish it outside the jig?

My only consideration outside aesthetics and strength (not a highly stressed part) is that the top of the T needs to be smooth. I can do that with a high inductance easy enough with MIG, but I've been tigging these in the past (10 units total to date). Now that I'm making volume, I want to go with the cheaper process. As long as no one gets blisters, I don't think they could care any less how they're welded.

 

[dragoneggs]

I'm no fixture expert but I like V grooves. Tends to take any slop out of the fixture compared to tabs or pins on flat surface. Design so you can easily tack without having to move the part during. My :2cents:

 

[Jim Timber]

The mouths hold the tube in orientation, so having tabs is sufficient on this one. I still agree with you on the v bedding for rounds.

I am thinking maybe a V groove bed with toggle clamps attached to a backbone would allow access to both sides of the joints.

 

[dragoneggs]

The mouths hold the tube in orientation, so having tabs is sufficient on this one. I still agree with you on the v bedding for rounds.

I am thinking maybe a V groove bed with toggle clamps attached to a backbone would allow access to both sides of the joints.

I like toggle clamps too. Make sure you don't have plastic tips on them... ask me how I know. :duh: Although just using for tacking, should be no issue.

 

[Jim Timber]

I don't buy the ones with plastic tips. :laughing: I started welding one of these last night so I could build the fixture off it and accidentally set it on a scrap of UHMW that was in the debris on the floor after welding it. It came off, with a little effort. :laughing:

I'd like to fully weld these in the fixture if I can, but I'm not **** bent on that. I'm getting a clearer vision of the jig I should make. I think it'll work pretty slick.

 

[Shield Arc]

Would you make it so the whole joint could be welded in the fixture or just to tack it and then finish it outside the jig?

I would use the fixture just for tacking. Remove the T from the fixture, put a square on it. Then I would know where to make my first weld.

 

[dragoneggs]

I would use the fixture just for tacking. Remove the T from the fixture, put a square on it. Then I would know where to make my first weld.

What does he know?

 

[Shield Arc]

What does he know?

Before doing this, or taking any of my advice you should consult with the resident welding expert!

 

[dieselcrawler]

Lol... yup... says the guy who has forgotten more welding knowledge than I will ever be exposed to!

 

[Mysfyt]

Do these have to be water or air tight?

 

[Jim Timber]

Do these have to be water or air tight?

Nope, but they end up that way with TIG. They also don't need to be all that square, but they end up that way unless I over cook them and it pulls the long part into a curve around the stub. That's still not enough of a defect to make a reject either.

 

[Shield Arc]

They also don't need to be all that square, but they end up that way unless I over cook them and it pulls the long part into a curve around the stub.

Jim do you know how to heat shrink?

 

[Jim Timber]

Yep, the only reason I keep my O/A rig is the rosebud (and cutting torch for when my plasma won't do it).

But these aren't an issue. It's a tool that the very end of is all that matters and the customers couldn't care less if the shaft is tweaked a little. Compared to the hack quality competing products, I'm still making top shelf in the market.

The diameter of my pipe is slightly larger than the diameter of my 1.25" end mill I use to fish-mouth with. So there's a slight mis-match at the crotch of the joints. TIGing those seems to pull the tube, so maybe if I'm MIGing them it'll be less heat soak and shrinkage along with less pull?