Different steels

[bootzey]

Hi All. New here and new to welding.

I'm producing a prototype on a small budget and the welding is getting expensive. So I brought a cheap welder and intend to "teach" myself, I have lots of scrap!

The problem I have is I've got some 80mm x 3mm box section that I want to mount 50mm tubes in each end. So I had some "lumps" turned out of solid engineering steel 74mm2 x 30mm. The tube mounts in them. Now I want to mount the lumps in each end of the box and I've just read it's difficult to do this.

What would any of you think of say drilling a 10mm hole through the box into the lumps, inserting a bit of 10mm steel tube, then creating a puddle of weld to join it all together?

I've thought of grinding a strip out, say about 50mm long, inserting a length of 10mm bar, then welding.

Any thoughts, hints or tips most welcome.

Many thanks

Dave

 

[Kent]

Mmm,
What is it doing? could you not just cap off the 80 box an weld the 50mm tubes directly to the caps? The trouble is when you haven't done much the biggest tendency is to over think and over complicate things. the weakest point will be the tube or the box wall if your welds are good enough.

If it needs to be dead square its not something for a new guy though

 

[daleyd]

What welder do you have?

Should be easy enough with a MIG welder (Roll of wire and gas bottle type), it will be doable with an arc welder (Welding rods type) but may take a bit of practice.

How strong does it need to be, if its structural you don't want to be taking chances.

A picture or drawing may help visualise what you are doing.

 

[norlander]

need a rough drawing, if its similar to what I do sometimes, you cant weld round the insert to the tube as it will interfere with the fit of the other component?, thus I drill and then weld thru and round the hole to retain the insert.
drilling through and inserting 10mm bar instead of tube might give you a better chance of welding a stronger set up??

 

[Kent]

is it only me that's lost with the descriptions now? post a sketch and tell us what it must do, I get the distinct feeling your over complicating what is a simple thing (which tends to push prices up)

 

[cianh91]

is it only me that's lost with the descriptions now? post a sketch and tell us what it must do, I get the distinct feeling your over complicating what is a simple thing (which tends to push prices up)

I'm not sure if I'm lost with the description or understand it perfect if what it sounds like your over complicating a very easy job a sketch would clear this up but could you not cut your box 10mm shorter and weld the edge all round ?

 

[bootzey]

Thanks for the replies all of you...much better than a car forum I was on.

Sorry for my description, inventors are notorious for over complicating/engineering things.

Sketches are a bit difficult as I don't want to potentially invalidate future patenting.

Basically it's 50mm tube inside each end of a 1 metre length of 80mm x 3mm box. I've got them positioned in with the lumps of engineering steel, but they need securing with weld. It's more about the join resisting movement by leverage rather than a need for tensile strength as they have a light weight on. However, there is a lot of leverage as the part moves.

I read engineering steels aren't easy to weld to basic black steel, so I'm looking at ways around this.

I think Norlander gets it...effectively making a stud I think?

I also thought about grinding a slot through into the lump say about 10mm deep, placing a short length of 10mm solid in the slot then welding it, effectively creating a long wedge in all sides of the box.

I've got a basic ac arc welder that goes upto 130 amps. It came with a pack of 2mm 6013s but I've also brought 3.2s of the same.

Just trying to reduce the odds of making a hash of it and wasting 6 weeks work!

Thanks again
Dave

 

[Bill Edwards]

If you can tell us the grade of the engineering steel it might be possible to say what it'll weld like, and how.
A lot of things can be done with a 312 dissimilar rod.

Or if i'm reading it right, you're thinking of drilling a 10mm hole through the lot and inserting a piece of 10mm bar to act as a pin?
That pin would have weld on each end which would only need to be enough to stop it sliding out, not to take any actual force.

 

[daleyd]

I think a sketch of just the parts you want to weld/ join would help hugely- we don't need to know what it's for or what any of the rest of it is doing but without that we are just guessing.

I can't see how that would have any potential patent issues.

 

[BoatBuilderDave]

80mm x 80mm x 3mm box sounds pretty heavy => this needs to be strong?
If that's the case, and you are new to welding, consider carefully what happens if this fails.
Mig in particular can lay a very pretty weld which is about as strong as chocolate if you don't do it right.
Test pieces and the sledge hammer test are at least a start.

 

[Kent]

Don't get fluffy about patent, its a turning shaft right- you cant patent anything that's already done that way and trust me it will be. Interlectual property is another matter and that will belong to the guy who tells you how anyway if you push it (not that any on here give a monkeys about helping a chap out).
Engineering steel? As in EN8 why did anyone do that then, could have turned it out of M/S- I seriously doubt this is a good way of doing it overall though
The design sounds like a stinker at present, what's needed is a fag packet sketch and an idea of the trueness required and the forces and what / how it all fits into / up to.
A lot of us will have worked on weapon systems and much prototyping without even knowing it, used to refer to stuff like that with just a drawing as a "joblet". You cant talk about it because you don't know what it goes into making and frankly don't care