Machine Shop Fail, Tromel Trunnion Wheel Repair

Topper Machine LLC sees many different kinds of jobs. Not much surprises us anymore, but this one did. Watch as we do a successful repair, only to have our glory stolen by hidden damages in the end. Lessons learned for us, but if we don't have failures, we will never learn to be better.
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[@EngineersWorkshop]

Those wheels look like a good candidate for a hub with a shrunk on 1/2" thk steel tire. Tire could be 4140 or such to be harder yet still replaceable. You should offer that product to them as an upgrade.

[@TopperMachineLLC]

I would be afraid to do anything like that. These wheels are the consumable part of the trommel. The tire on the drum is the expensive part. You want to be softer than that but a single piece. I do some that are cast iron. They have a designated minimum diameter.

[@EngineersWorkshop]

@@TopperMachineLLC I understand but it would be a simple matter to do a cast-iron Hub with a 1018 tire that would give you something to replace without remaking the entire part. Shrink fit would keep the surface of the iron hub in compression which would be a good thing

[@EngineersWorkshop]

@@TopperMachineLLC Similar screens are used in wastewater applications, the Atlanta ones are about 30 ft in diameter, but I think they are supported by a center shaft in that location

[@TopperMachineLLC]

@@EngineersWorkshop but if that tire ever started to break up, it would cause significantly more damage than just a little chunk coming out. The option we are exploring is turning it down and rebuild with weld.

[@highlandermachineworks5795]

Fart sniffer? Na, that's literally just an EGR system.

[@bostedtap8399]

You can't win them all, good idea on ultrasonic pre machine inspection. Thanks for sharing.

[@TopperMachineLLC]

My next video is doing a UT test. Surprising how bad it really was.

[@muhammadafshohilanam4665]

what thats filler metal used sir, and as i know 4140 is more sensitivity about crack on HAZ, Hydrogen effect , can u make it with right welding process parameter with controlling Heat input and slowly cooling (u can used thermal insulations in there) and last used PWHT

[@paulcharman44]

This is classic rolling contact fatigue damage caused by a combination of overloading the surface of the wheel and very poor material with excessive inclusions. You had no chance, and in my view, this was always going to happen at some point. to be honest I am not sure what re-skimming would do except even out the surface stresses and it may be that the heating cycle of the welding process may have been a contributing factor. But as I said you really had no chance with this wheel. Great videos and content.

[@johnplump3760]

Josh: Is it possible to machine this down and then build a sleeve that is press fitted over the unit by shrinking and heating. Then weld in 4 places just to hold it. This seems a solution. Give me your thoughts. I believe this would be less expensive than buying a new one.

[@markledford4420]

Cut it down weld it up idk I always wondered if LA 100 might wire would be a good option?

[@edswider9309]

What ever happened to Keith fenner from New England

[@ypaulbrown]

the Miller [FS filter] Hilarious....I am not sure if the 70s-3 is softer than the 70s-6 wire, the 70s-6 has more silicon as a deoxidizer and slightly more manganese. the S3 has 26% elongation compared to S6 28%. the Charpy V notch for S3 is 87 ft lbs at -20 degree f and S6 is 71 ft lb at -20 f...this is data from Lincoln Electric for their Superglide series of wire as welded. 70s-3 applications are pipeline, pressure vessel and structural, while 70s-6 is automotive repair and structural and medium to heavy mill scale material while 70s-3 is for clean to light mill scale material. ....both are recommended for sheet metal....tensile strength with co2 is 74 ksi for 70s-3 and 78 ksi for 70s-6, those are as welded figures.....hope this helps, cheers from Florida, Paul...great video on this repair.....even though it blew up in the end!!!!!

[@shmulikklapwald9884]

Also, the comment of steel tire is even better to the rewelding option.

[@johnplump3760]

I have to say that you are "MULTI-TALANTED!!" Opening a shop on your own, doing what you do, requires "TALANT". some things can be learned but sone comes with intuition. I my opinion, you have both. i could open a shop but do not have the talent to be able to do all the different things that you do. I also admire how you will not do a halfass job. All your work is top notch (EXCELENT). This is why you are busy. Keep up the excellent work.

[@TopperMachineLLC]

Thank you. In this region, you have to have a lot of skills and be able to do a lot of different things to survive.

[@markblack9987]

Send it to Harper Corp. of America Charlotte NC

[@mrfarmall-vk4gw]

I like the pre heat table, that's a good idea 👍

[@TopperMachineLLC]

Works great and was simple to build.

[@robmosher362]

Very interesting video. You are an exceptional machinist. I had to produce videos with narration and was informed that I started to run the narrative together with “ah’s and um’s, something we should catch and correct, if that is happening.

[@alanm3438]

When I saw your helmet fan I thought it could pick up a fart and sure enough your answered my question. I do not know anything about the different kinds of steel but how do chunks fly out? Was it impurities in the casting? It is to bad that you found more and that it is not repairable. Good to see you and the video this morning.

[@TopperMachineLLC]

It works amazingly well to stink you out. Lol. The shelling comes from repeated load in a single direction.

[@CothranMike]

@@TopperMachineLLC Exactly, just as we rotate our tires on our cars for PM this needs to be done for these poor rotors much more frequently than the accidental reversing of direction obtained in normal usage. I saw no directional arrows and assume any painted marking will not survive the environment.

[@aaronbaird3533]

Would've been interesting to take another pass off to see what else popped up.

[@CothranMike]

And very dangerous for the machinist/operator than is warranted.

[@hobtink]

I was wondering if the fail/surprise was going to be the entire cap getting caught in the cutting tool and all it a major portion of that peeling back off the wheel. Is there a reason that a shrink fit cap cannot be made and press fit over it? Or would the material hardness needed for the cap not be compatible with sweated, or heated and the wheel chilled to do a light press fit if a new outer cap surface?

[@TopperMachineLLC]

they must be a solid material as the weight and rolling action will cause a "cap" to start moving and eventually fail as well. These wheels if properly maintained will last a very long time, if not they shell out like this one.

[@houndog7882]

Could you send it out for X-ray to see how bad things are before scrapping it? Might be a candidate for powder welding, or whatever Adom70 does.

[@TopperMachineLLC]

Check out the second video. I did an ultrasound on it. Totally junk.

[@passenger6735]

Are those holes, voids in the casting during manufacture?

[@TopperMachineLLC]

No. It is caused by the rotational stresses of carrying the weight of the trommel.

[@CothranMike]

@@TopperMachineLLC Off the top of my head, distributed stress should be considered so that 1) each traumatised mistreatment to the wheel bears a little less weight over time and so that 2) each traumatized wheel has a fatigue Factor more in fitting with rotational replacement. Rack them in groups of 3 each, have them capable of being dropped out of the rotation and another rotated into its place. Additionally you might consider using the triple wheel system. Large non replaceable rubber wheel to be preserved for longer time but made in segments for replacement in situ for a small down time. This runs around the trommel tube so freewheeling for replacement will be a problem under load. This wheel runs indirectly on a support layer of rollers which freewheel on a third wheel which itself is replaceable. The addition of heat for drying is the party responsible for the failures. I see that roller specificity as rewelded poorly with lousy penetration prior to your working on it. A metal is needed which can resist pressure and heat, rolling fatigue, and constant usage with no down time yet easily able to be diameter skimmed on a PM rotation. Poor thing it never takes a break until it breaks bad enough due to a poor PM program, as you mentioned. Most solutions to these multi failure point prone items can be more expensive than a proper PM program though so simple IS best with-and-requiring preventive maintenance stepped up.

[@arthur8284]

I don't understand what problem there was during the welding phase... but I really have to say that you're really good at machine tools 😉👍

[@jimsvideos7201]

Liquid penetrant inspection only indicates voids that are open to the surface, but it's quick and relatively convenient.

[@GardenTractorBoy]

It is amazing that the damage came to the surface with the final cut

[@TopperMachineLLC]

Yeah. That one surprised me. Next video I do will be with ultrasound testing to find these problems.

[@normanfolger9508]

I vote for the steel tire also. We had a machine that used cast iron rollers in need of replacement. Turned them all to a uniform size and made steel tires for them. I don’t remember the alloy but they lasted several years before needing to be retired

[@martinlawson1476]

You must have problems if you can not stand your own farts 😀

[@anthonycash4609]

Josh could you have welded a harden sleeve on it and turned it down smooth or does the diameter come into play then. I've never had the opportunity to work on a trommel.

[@TopperMachineLLC]

There is no acceptable repair. A sleeve could break and damage the tire on the trommel. These wheels are consumable at $2k each. Tires on the trommel drums run $100k and up for the size I work with.

[@brendanshemeld7803]

I know its been long time since you recorded this Fail attempt. Did you ever think of putting a steel band up to the right size required if you could lathe the cancer out of the wheel. And bolt 🔩 it on the wheel an have a few key ways to also help it from turning if any bolts broke. I'm not a engineer but I'm sure you could do something like this and if band was damaged you could either replace or lathe till needed replacement. If you get more like that why not try. And if this one is still around why not try and do my idea if possible. Good luck

[@TopperMachineLLC]

Due to the weight carried be these wheels, it is not possible. It will just fail and throw a bigger chu k resulting in more severe damage. These are a one and done item. As long as you skim cut them every so often,they last a long time. Let the. Go like this one did and they will cause alot of damage.

[@hansslob6749]

Looks more like a casting error then lag of maintenance.

[@shmulikklapwald9884]

To my opinion the wheel was supposedly be machinned about 1/8" deep, rewelded all over and remachinned.

[@TopperMachineLLC]

Not acceptable repair for this application.

[@CothranMike]

@@TopperMachineLLC There is no window of rest while rotating for these smaller wheels, unlike the large rubber they support. That rubber has at least two ways to rest while attached to the trommel. Those times while not in contact with the support wheel(s). Depending on the included angle between the two support rotors the subtended moving arcs provide a source of relative relief for the period of time out of contact. The RPM of the trommel in this application for (drying wood chips?) is significant to the problem of course. The level of heat and the constant reheating to maintain the drying level over time will break down most adhesive used to bond rubber to steel structures so I assume the rubber tire around the trommel is cast whole making it expensive to service and/or replace inexpensively. Sounds like a purpose build machine should do a better job for the actual usage to which this machine is subjected?

[@ypaulbrown]

at the shop I worked in 2007-2010 ,we had an old clapped out lathe [24"x260"] that we put a VFD on, we could run at probably 1/4 rpm if we wanted.....anyway, we did weld build up on shafts and what ever.....just put the MIG gun on the tool holder.....and let her RIP....maybe you need something like that in your Arsenal? machine down the part and build back completely? Best regards, Paul in Florida

[@TopperMachineLLC]

I actually have roller stands that I am adapting to this purpose. Takes up way less space than a worn out lathe, and is extremely versatile.

[@ypaulbrown]

@@TopperMachineLLC sounds good.....what are you using for an automatic feed of the MIG gun? that was the great part of ours, feed rate was always the same, only rpm changed.....and the build up was really smooth......cheers, Paul

[@TopperMachineLLC]

@@ypaulbrown I just hand weld now, but planning on building a feed system. Really not that complex, just need to do it.

[@ypaulbrown]

@@TopperMachineLLC can't wait to see what you come up with.....cheers, Paul

[@herb187]

How about spray weld?

[@TopperMachineLLC]

Cannot be repaired. If not maintained by skim cut, they are destroyed.

[@seansysig]

Couldn’t these be spray welded?

[@TopperMachineLLC]

No. They would shell out worse yet. They are a consumable

[@CothranMike]

@@TopperMachineLLC So, all that divots is not rolled? Grins aside, what I am seeing is recrystallization of the steel atoms after rolling fatigue, same thing happens to tool steels used in rolling mills both hot and cold types. A hard and thorny problem with other issues if it is attempted to be repaired in what most consider to be a normal fashion for rollers?