Chipper drum failure

[southsoundtree]

I'm curious how close a real world balance gets to truly balanced, and at what amount out of balance it will start to matter.

 

[flushcut]

Idk if I said this already but a new drum from Vermeer is $11,500ish, that doesn’t include the shaft. A different company has drum and shaft available for $9,500ish..this weld cost me a couple hundred bucks.. that being said I don’t want to have to take this machine apart again if the weld fails.. I’ll get a second opinion on the welds. My understanding is the drum is held to the shaft via wedges with large bolts.. my current drum has 5,9000 hours and has never been off the shaft in 20+ years.so I’m not gonna try. Lots of wear on the drum, I don’t think welding this crack closed will have any significant bearing on the drum’s “balance”.

It certainly looks like a “couple hundred bucks” fix not repair. It looks like there is undercut, porosity, inconsistent bead profile, and poor blending, all the ear marks of future failure. Just saying but I wouldn’t be happy with that, at all.

 

[Matias]

What’s with the big crack on the side of the pocket visible in the photo?

Also, I don’t like that inside taper design of the drum, seems that would allow a certain amount of flex in the skin that might cause it to be more prone to delamination.

Hopefully that repair holds up well for you, and is balanced well enough to work properly!

That big unwelded section on the edge is definitely what worries me the most. If the unit is run and fails and someone gets hurt, does the welders insurance cover it? does it even matter if it continues to cost you down time?

 

[Bigdog12]

It certainly looks like a “couple hundred bucks” fix not repair. It looks like there is undercut, porosity, inconsistent bead profile, and poor blending, all the ear marks of future failure. Just saying but I wouldn’t be happy with that, at all.

Fair enough, welding isn’t my forte but I will definitely have another set of experienced eyes look at it before I go through the trouble of putting it back into the machine.. making me think harder about biting the bullet for a new drum…

 

[Bigdog12]

That big unwelded section on the edge is definitely what worries me the most. If the unit is run and fails and someone gets hurt, does the welders insurance cover it? does it even matter if it continues to cost you down time?

I’ll take it to another shop for a second opinion.. I doubt their insurance would cover anything.. I run one crew and this is my 3rd, oldest, and smallest chipper, so it’s costing me more in shop space than downtime.. it needs to be useable for pruning/ under CDL driver, or sellable.. either case drum needs to be functional.

 

[Bigdog12]

I'm curious how close a real world balance gets to truly balanced, and at what amount out of balance it will start to matter.

Me too, this thing had heavy wear spots, didn’t seem perfectly cylindrical at all.. never bounced, or “felt out of balance” and the bearings were fine, so idk

 

[flushcut]

Fair enough, welding isn’t my forte but I will definitely have another set of experienced eyes look at it before I go through the trouble of putting it back into the machine.. making me think harder about biting the bullet for a new drum…

I would. That other shop did you dirty.

 

[southsoundtree]

Seeing that drum, I wouldn't feed that machine.

Bad enough when (extremely rarely) a knife comes loose (likely due to something improper), but a monster drum shrapnel-ing under monster power has death and lawsuit written on it (I'm and arborist not an attorney).

 

[southsoundtree]

Losing a lawsuit is crazy expensive.

Depending a lawsuit successfully, way more than 10k.

 

[Bart_]

Might be worth a go at really cleaning everything you can get at to check everywhere for presence of any other cracks forming that haven't actually failed structurally, but are beginning. Part of the design of such things is fatigue # cycles life. Perfectly good design maybe but a critical part can just get too old. Maybe check into how many hours a drum is supposed to do and/or how many hours others have gotten safely from their same model drums. At least get a feeling where yours sits in general terms.

 

[Tom Dunlap]

Input from a millwright and a metallurgist would be more valuable than a weldor

 

[data farm 26]

Is there a precedent for this type of repair? I would have guessed it was 'totaled' like what happens to a car...

 

[southsoundtree]

Is there non-vested interest in this welder?


Does he have a lot to lose if this goes wrong, or is it a little operation? Is this a welding biz worth $0.03M or $3M (arbitrarily).


How fast does a drum spin compared to a truck tire?

 

[evo]

it needs to be useable for pruning/ under CDL driver, or sellable.. either case drum needs to be functional.

you can’t ethically sell this machine with a drum like that unless it’s proper fixed. If I sold the machine I’d take the drum out of it.

 

[Lumberjack]

What if he puts 1k hours on the chipper with no issue? 500 hours? 100 hours? 2k hours?

 

[Bigdog12]

Is there a precedent for this type of repair? I would have guessed it was 'totaled' like what happens to a car...

It isn’t unprecedented, I’m just not totally familiar with the process. I believe landmark machinery repairs drums like this fairly often. Hell they said they could repair the drum out of my BC2100xl (the photos from the beginning of this thread). Ended up replacing that with a new one. This seems much more “repairable” than that machine was

 

[Bigdog12]

you can’t ethically sell this machine with a drum like that unless it’s proper fixed. If I sold the machine I’d take the drum out of it.

I think that begs the question, what’s “properly fixed”mean? According to the guy who welded it, it’s fixed.. according to some tree guys I’ve never met on the internet it’s going to self destruct and kill somebody.. ethically, I would sell this machine with that drum in it, I would simply disclose the drum had been welded, buyer make up your own mind, used equipment is just that, used.. honestly though I want to keep the machine and use it. It’s a tough call. The machine is worth maybe 20k, so to drum half the total cost of the machine on a single part seems silly. To replace the whole machine new though your prolly pushing 100k… still contemplating what to do tbh