EFM 520 broken auger

 
t185
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Post by t185 » Wed. Mar. 21, 2018 2:16 pm

Afternoon gents!
Been a while since I've visted this site. So long in fact that my UN no longer worked so I had to start a new account.
Anyway....
Had to replace my auger on Tuesday this is the second time in two years that this has happened. Last time it broke I had it welded and replaced the same day. No big deal other than I had to take a day off from work. This time I replaced it with a spare that I had ordered. Wondering if this is a common problem or maybe I just had a bad auger to begin with. Odd that the shear pin didn't break before the auger
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Notice the stress crack in the second photos. I'm going to have this one welded to have as a spare
Last edited by t185 on Thu. Mar. 22, 2018 9:44 am, edited 1 time in total.


 
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freetown fred
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Post by freetown fred » Wed. Mar. 21, 2018 2:39 pm

Anything round that takes stress I've always cut through- drilled both ends, pinned & then welded. Ya got the time, do it right. Any decent machine shop should be able to do it & not break the bank. Just an old farmers thoughts. Glad ya had the spare.

 
t185
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Post by t185 » Wed. Mar. 21, 2018 2:56 pm

freetown fred wrote:
Wed. Mar. 21, 2018 2:39 pm
Anything round that takes stress I've always cut through- drilled both ends, pinned & then welded. Ya got the time, do it right. Any decent machine shop should be able to do it & not break the bank. Just an old farmers thoughts. Glad ya had the spare.
Good friend is fixing the shaft today, pinned and welded.

Still at a loss as to why the shaft would break before the shear pin?

 
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Post by Phil May » Wed. Mar. 21, 2018 2:59 pm

Just buy a new one. After stainless breaks the weld will be a weak point. You can fix to get out of a bind but it will always break at the most undesireable moment. I fixed a lot of stuff over the years that needed to be scrapped.

 
t185
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Post by t185 » Wed. Mar. 21, 2018 3:08 pm

Phil May wrote:
Wed. Mar. 21, 2018 2:59 pm
Just buy a new one. After stainless breaks the weld will be a weak point. You can fix to get out of a bind but it will always break at the most undesireable moment. I fixed a lot of stuff over the years that needed to be scrapped.
That is what I thought. The first time this shaft broke I had it welded. When it broke the second time it didn't break at the weld but about an inch and half up the shaft.

 
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northernmainecoal
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Post by northernmainecoal » Wed. Mar. 21, 2018 3:10 pm

The shear pin should be breaking, not the auger. sounds like something else is going on

 
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Post by Pacowy » Wed. Mar. 21, 2018 3:21 pm

Suggest getting a new spec shear pin to be sure on that, and check that the fire is not too low in the pot. It looks like your problems are right around where the auger could get cooked.

Mike


 
t185
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Post by t185 » Wed. Mar. 21, 2018 3:25 pm

Pacowy wrote:
Wed. Mar. 21, 2018 3:21 pm
Suggest getting a new spec shear pin to be sure on that, and check that the fire is not too low in the pot. It looks like your problems are right around where the auger could get cooked.

Mike
What would cause the fire to get to low into the pot? To much air?

 
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Post by Pacowy » Wed. Mar. 21, 2018 3:27 pm

Yes. After a long run there should be about a 2" ring of dead ash around the fire. If the ash ring is bigger than that you need less air (or more feed).

Mike

 
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Post by t185 » Wed. Mar. 21, 2018 3:43 pm

Pacowy wrote:
Wed. Mar. 21, 2018 3:27 pm
Yes. After a long run there should be about a 2" ring of dead ash around the fire. If the ash ring is bigger than that you need less air (or more feed).

Mike
I'll check that out. Last I checked I was running 5 tooth and six air.

The second photo shows a stress crack about 1/2 way down the shaft, well past the pot. And idea what would cause that?
Last edited by t185 on Thu. Mar. 22, 2018 9:45 am, edited 1 time in total.

 
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Post by Pacowy » Wed. Mar. 21, 2018 4:02 pm

Sorry I don't know on that one. Maybe a rock stuck at the pipe opening and a way-too-hard shear pin?

Mike

 
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Post by freetown fred » Wed. Mar. 21, 2018 4:49 pm

I also would check on the shear pin quality. P, I've never had an auger re-break after pinning & welding. I'm talkin more heavy duty then movin coal. I repeat--a GOOD machine shop.

 
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Post by windyhill4.2 » Wed. Mar. 21, 2018 8:28 pm

Am i imagining things or are the auger flights worn real thin at the break point ?

 
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Post by europachris » Thu. Mar. 22, 2018 8:52 am

In my (slightly professional) opinion, it appears the auger is being flexed somehow as it rotates. The weld creates a stress point and the fatigue crack will propagate from that point until it finally shears. If you take a good look at the break and then compare it to some images easily Googled on stress fractures in steel, you'll be able to tell what sort of failure it was.

I'd look for some sort of misalignment between the auger drive and the tube. Might even be a badly machined pot or other component.

Chris

 
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Post by Rob R. » Thu. Mar. 22, 2018 9:19 am

The auger could have been bent before it was installed.

I agree with the others that it would be a good idea to install a new EFM-sourced shear pin, and make sure that you can easily turn the auger with the hand-crank. If it takes more than a slight effort to turn that hand crank, you have some sort of alignment/setup problem.


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