Which weld type?

[Davek0974]

Hi all
I need to make some wheels for a traction engine like this...

http://www.tractiontalkforum.com/picture.php?albumid=490&pictureid=7701

I have a decent MIG welder but these were done with stick, I have not done arc welding before.

Would I be able to get a radius by mig welding or would it have to be arc welding?

Dave

 

[rtbcomp]

Link doesn't work

 

[Davek0974]

Sorry, it seems you need to be logged in

Anyway, roll a strip of steel into a hoop, 10mm thick by 100mm wide and 600mm dia.

Then roll another hoop of steel on edge,place this ring inside the first one and weld in place,this forms the outside part of a traction engine wheel. Spokes and hub are then added.

The welds need a radius fillet.

Does that help at all?

 

[penfold]

It won't work unless you sign up I think.

 

[Davek0974]

Try this one..
http://www.flickr.com/photos/87791108@N00/6476298147/lightbox/

 

[rtbcomp]

That's better, but not as good as attaching an image.

http://www.mig-welding.co.uk/forum/showthread.php?t=12020

 

[ChrisJohnsSculpture]

To a certain extent it depends on the machine, you don't necessarily get a huge amount of control over the weld profile with MIG unless you've got one of the fancy electronic ones.

However on a fillet weld on 10mm plate my main concern would be getting adequate penetration. Certainly a full penetration fillet weld would on plate that thick would require a fairly heavy serious amount of current.

I'm also not 100% convinced that the wheel in the picture is made by welding a flange onto a ring. I would think it more likely that it was rolled from angle and then hot riveted to a wider ring. but its hard to tell for sure from the picture.

 

[hotrodder]

Thought i had déjà vu... http://www.mig-welding.co.uk/forum/showthread.php?t=32161&highlight=traction+engine

I'm also not 100% convinced that the wheel in the picture is made by welding a flange onto a ring. I would think it more likely that it was rolled from angle and then hot riveted to a wider ring. but its hard to tell for sure from the picture.

^^ that's what it looks like to me although none of the pics in either thread have enough detail

With regards to welding it... to get the fillet radius you need a concave weld face. Excessive concavity is potentially a bad thing as the surface is put in tension when the weld cools- think, more prone to cracking etc

 

[Welderpaul]

Deja vu indeed...

If you have the right machine and skills it could be migged and made to look nice. Stick would take forever. Mig done right would be certainly strong enough. As to achieving a radiused weld..unlikely. A radiused weld would signify to me not enough current and in any event you would be unlikely to acheive a consistent weld profile that would look reasonable. It will always look like two rolled flats welded together and lack the finesse that the real thing has. Distortion will be an issue as well.

Like platting fog.

 

[GrahamGKD]

I'm also not 100% convinced that the wheel in the picture is made by welding a flange onto a ring. I would think it more likely that it was rolled from angle and then hot riveted to a wider ring. but its hard to tell for sure from the picture.

I didn't think welding as we know it was invented when those things were made - just the process of heating in a forge and welding by hammering the white hot parts together?

As Paul says - if you did weld it I would have through warping would be a nightmare! Sorry I can't offer any more constructive suggestions

 

[Davek0974]

Hmm, well one thing I do know is that many many model engineers make these by welding so it most certainly works ok. The secret I learnt today is that most will run a finger covered with body filler round it to create the effect.

I know it does not need full depth welds as the stresses are low relatively. I have a 160A mig which will also do 130A arc welding. I also have 0.8mm wire and tri-mix gas or co2. The method seems to be to weld 3" on one side, flip over and weld 3" diametrically opposite and carry on like that. Any crap gets ground back as usual, then it's tarted up with the spackle.

I am fairly confident of my mig work but have never really tried arc welding. I am thinking that by keeping the weld joints at 45 deg to the bench I will always be welding downwards so that should assist maybe?

I have some scrap of similar dimensions so will have a go first.

Oh and the originals were most definately not welded

 

[ChrisJohnsSculpture]

While I wouldn't want to commit myself too much on the engineering aspects in terms of safe working loads etc, I'm inclined to agree, on first instinct, with the assessment that it's probably not a very highly stressed joint and what you suggest seems fairly reasonable.

Doing some tests on similar gauge scrap is a good idea, I would suggest welding up some butt and T joints, sticking them in a vice and hitting them with a hammer until they yield. If the metal bends before the weld or metal in its immediate vicinity fails then you have reasonable cause for confidence.

In terms of MIG vs stick I would say stick with what you know, regardless of the ideal optimum process you are likely to produce better welds with a process you are familiar with than one you aren't.

As others have said a full length (circumference) weld is likely to start to cause problems with distortion and a 160A machine almost certainly won't get full penetration on 10mm plate ....it's really a question of how the final component is stressed.

In terms of welding sequence it might be considering putting stitch welds at 120 deg to each other rather than directly opposite (180 deg) as this tends to equalise the stresses in rings better over the whole process (this is why cast wheels tend to have an odd number of spokes...as an aside you will also notice that many cast iron wheel have curved, s-shaped spokes which helps to absorb the radial stresses set up).

How many 'stitches' you put in is another issue, obviously the more welding you do the greater the risk of distortion which needs to be weighted against the additional strength and margin of safety they will provide.

 

[the artfull-codger]

the originals were rolled from tee section & the welded together at the joints,front rims a single tee & the back rim two tees either riveted together with straps or a continuous inner ring, the front had a steel tyre riveted on [so the tees didn't wear,] in a number of sections to allow for stretching etc, the rear wheels with the two tees were fitted with strakes,angled so as not to be bumpy,they were angled in over looking from the top so as to force the wheels towards the centre as opposed to forcing them off the axle,finally built up with the spokes & the hubs cast in to the spoke ends in the foundry & the hubs were bushed for wear. the palm ends of the spokes were apparently welded to the spoke stems. A colleague of mine built his 6" garret wheels the same way, as for a miniature, roll the rims up,weld the ends,back in the roller & then weld in the tees usually a few inches at a time & opposite etc you'll have a ball ache rolling the tee part flat with twisting,just get them profile burned out of plate.if you can't get a radius you can dress it up with an angle grinder & fill in with a filler.
slan go fol ps my preference is stick but that's just my personal prefere
nce

 

[Davek0974]

the originals were rolled from tee section & the welded together at the joints,front rims a single tee & the back rim two tees either riveted together with straps or a continuous inner ring, the front had a steel tyre riveted on [so the tees didn't wear,] in a number of sections to allow for stretching etc, the rear wheels with the two tees were fitted with strakes,angled so as not to be bumpy,they were angled in over looking from the top so as to force the wheels towards the centre as opposed to forcing them off the axle,finally built up with the spokes & the hubs cast in to the spoke ends in the foundry & the hubs were bushed for wear. the palm ends of the spokes were apparently welded to the spoke stems. A colleague of mine built his 6" garret wheels the same way, as for a miniature, roll the rims up,weld the ends,back in the roller & then weld in the tees usually a few inches at a time & opposite etc you'll have a ball ache rolling the tee part flat with twisting,just get them profile burned out of plate.if you can't get a radius you can dress it up with an angle grinder & fill in with a filler.
slan go fol ps my preference is stick but that's just my personal prefere
nce

100% spot-on the original rears on this engine were held together with a hoop inside the tee's, all wheels on this one will be rubber vulcanised so no strakes etc. Spokes are all laser cut, hubs are cast iron with bronze bushings.

I will stick with the mig I think.

The tee rings were rolled edge-on and are lovely and flat. I have done a full prep on the rim joins and applied a root weld and capping to inside and outside then cleaned back flush with the grinder. The tee ring is currently joint-welded and tacked in to the rim, hopefully I'll get a chance to get some welding done this weekend.