[maker of things]

In a situation like that I don't feel one bit bad about telling the customer that I don't think it will work, but I will try it for them, no guarantees. If the replacement part is $300, they should probably have one of those on order. Even if your weld only lasts 1 day, that is 1 more day of running a machine until the replacement part gets there. Hopefully they are getting more than $30 a day to use the piece of equipment. So your fix, even if temporary, should be an extrememly good value to them. If the customer can't afford the $300 part and is going to hang the sccess or failure of their business on your $30 job, I would be inclined to not accept future work from the individual. IMO Hope it does work out though. Would be very satisfying to solve a puzzle like that.

[exnailpounder]

I explained to him that what I am trying to do is NOT recommended but he insisted so the ball is in his court. At least I didn't have to refund his money and it didn't take me long to pre-heat and re-weld it with new filler material so he is happy. I have an almost perfect track record for repairs staying repaired and not haunting me but I think I will see this one again. Next time he is going to have to pay up to get it welded again.

[Poland308]

If it does come back I wouldn't feel the least bit bad about charging him. Some customers will spend hundreds of dollars to fix or patch something they could buy new for the same price. I think they like the idea of having it "fixed". Will be interesting if it comes back. You don't often get to try different repair options on the same part to experiment.

[exnailpounder]

If it does come back I wouldn't feel the least bit bad about charging him. Some customers will spend hundreds of dollars to fix or patch something they could buy new for the same price. I think they like the idea of having it "fixed". Will be interesting if it comes back. You don't often get to try different repair options on the same part to experiment.

I asked him why he bought a 2 piece setup in the first place and explained that he thought it would kind of wedge itself together from use and would just stay that way. Maybe on mild but not heat treated Chromoly. I have some Inconel waiting in the wings for round three.

[noddybrian]

It's not that unusual on air tools to have a taper fit & if only subject to axial loads works well - for example CP9 air drill has it's own fitting but there is an adapter to K taper drill bits - these work fine & need quite a blow with the taper drift to get out - in a similar way morse taper on drills work but if you have a mill using a morse taper spindle tooling subjet to side loads won't stay put without use of a draw bolt - why a clay spade would be made this way is strange unless the taper on the shaft is meant to fit multiple heads on the same tool.

[echosixmike]

Silver solder/braze it? S/F....Ken M

[exnailpounder]

20161116_165333.jpg (34.48 KiB) Viewed 872 times

Love a challenge eh?

Keep us posted if it comes back, or not.
Cheers

IT'S BACK! The ER80 lasted a bit longer but pulled out at the toes. This time I drilled it and put in a grade 8 bolt. This stuff is harder than a womans head to drill but a titanium bit went through it. Then I ran 3 hot passes of Inconel around it just for fun. I told the guy this is it. If it breaks now, take it somewhere else. At least he can put new bolts in it. Stay tuned.

[mpete53]

Are the pieces tapered?
From the photo both the shaft and the hole shinny and the shaft appears tapered. Is it possible the parts were designed to be a shrink fit where the outer piece was heated red hot and the shaft cold was driven into it. Then when the outer piece cooled it would shrink and hold onto the shaft. Ring gears on flywheels and rail road tires are installed that way.

[Coldman]

Sorry Exy, its gonna break again.
There is just not enough weld on it. You need to get it back into your shop and put another three stringers on it at least. Fill the fillet right up. Then the weld will be stronger than the parent metal and if it breaks, it won't be the weld.

[exnailpounder]

Sorry Exy, its gonna break again.
There is just not enough weld on it. You need to get it back into your shop and put another three stringers on it at least. Fill the fillet right up. Then the weld will be stronger than the parent metal and if it breaks, it won't be the weld.

Ahhhh.Coldie I hear ya. I put the heat to it this time, over 200 amps and did 3 passes, The problem is that it's an alloy that isn't recommended to be welded. My first attempt was 309l and it was a big old fat weld that snapped in the middle and this time it pulled out the toes with pre-heat and ER80. Hopefully the bolts hold up. He is able to change them out so if the weld breaks he can still use it.

[exnailpounder]

After further research, I think whats happening is creep. Anybody have any opinion.

[Otto Nobedder]

After further research, I think whats happening is creep. Anybody have any opinion.

If mpete53 is correct and it's a taper fit, then, yes. To weld that joint with a taper as a fit, one would hold back, as in a socket weld, so the shrinkage does not preload the hell out of the weld.

Steve S

[Coldman]

Creep happens at the intergranular level below yield stress in the parent metal. So far from the pics seen the welds have failed not the parent metal and therefore unlikely to be creep as the break must logically have happened above yield stress. I understand the parent metal is not meant to be welded but it appears to be hanging in there. If the welds are breaking they are not strong enough due to filler selection or size of throat. My bet is still on throat size. Put another 3 to 5 beads on it with your er80 and see what happens.


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[exnailpounder]

Creep happens at the intergranular level below yield stress in the parent metal. So far from the pics seen the welds have failed not the parent metal and therefore unlikely to be creep as the break must logically have happened above yield stress. I understand the parent metal is not meant to be welded but it appears to be hanging in there. If the welds are breaking they are not strong enough due to filler selection or size of throat. My bet is still on throat size. Put another 3 to 5 beads on it with your er80 and see what happens.


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OMG coldie...I put a shit pot of Inconel in there this afternoon. Don't have a pic yet but I thought about what you said so I stoked the fire and did what my macine could do. I hate having somethingcome back...thanks for you 2cts

[exnailpounder]

After further research, I think whats happening is creep. Anybody have any opinion.

If mpete53 is correct and it's a taper fit, then, yes. To weld that joint with a taper as a fit, one would hold back, as in a socket weld, so the shrinkage does not preload the hell out of the weld.

Steve S

This might turn into a lesson for all of us. I sat and looked a that piece after it came back for the 2nd time and wondered what I did wrong. I assumed that the impact it took wasn't a factor until I looked up creep. It's an impact tool and I thought I just needed it to stay in one piece, I neglected to think about creep... Your the resident brain here, what do U think?

[exnailpounder]

After further research, I think whats happening is creep. Anybody have any opinion.

If mpete53 is correct and it's a taper fit, then, yes. To weld that joint with a taper as a fit, one would hold back, as in a socket weld, so the shrinkage does not preload the hell out of the weld.

Steve S

Dammit Steve I already asked this question way back in the beginning... Should I have treated this like a socket weld and left a gap...????

[Otto Nobedder]

You say that as if you expect me to have an attention span...

Optimist.

Steve S