Maby in the wrong place but this d11n roller frame repair was something you might want to see. Hole size is 10.342 it took 2 passes of weld for buildup,
Nice job,sure better than strapping the trusty Bridgport to the frame. That line boring set up would sure be handy. RI
Welcome to the Forums rusty iron!:drinkup Thanks for sharing Steve. Is that 11 in a coal mine?
Why not machine it larger and put the O/S bearings in? lotsa weld is never a good thing.
I think I would have used Cat Special Instruction SEHS8972 and installed the oversize bushes on the Pivot Shaft ends myself. Personally I wouldn't be happy with the way the welding's been done to be honest, although I'll say here & now that if it works for you then go for it. A couple of questions: What electrodes did you use for the build up..? Did you pre-heat the structure because it's a casting..? For me the welding for the bore build-up should have been done circumferentially rather than across the bore as shown in the photos. The end of every one of those weld beads in the photos is a potential stress riser for a crack to start, especially as each one has been terminated right on the edge of the structure. 2nd IMO the bore really ought to have been machined a tad so that the weld was going on to "fresh" metal and you would have also had a consistent depth of build-up weld. Lastly I'd really have preferred to use a semi-automatic wire feeder hooked up to the boring bar to deposit the build-up weld. I'll have to take some phots of our boring setup the next time we use it. Ours is hydraulically-powered and includes a wire feeder head that we can attach to the boring bar to build up a worn bore. We can handle up to 20" bores with our rig. Usually a repair is done in 3 steps: - 1. Set up boring bar, get it aligned correctly with a good part ob the bore (if there is any) of whatever other reference points on the structure are recommended. Machine the bore even more oversize until the whole thing is a consistent diameter, whatever that is. This has the added advantage that if the bore is only slightly oversize you're actually not machining off maybe 90% of your build-up weld leaving just a thin layer that you hope has good pentration to the original structure. 2. Build the bore up with the wire feeder until it's sufficiently undersize to machine back to specification. 3. Machine to size. Sounds simple when you say it quick ..........
Sure are a lot of people criticizing the man's work here. Why don't you post a picture of a similar repair you have done and let him criticize your work?
If you note my post it says ....... "I'll say here & now that if it works for you then go for it" The way we all get better is to interchange ideas and suggestions. I thought I was being positive about suggesting ways to improve on a job, and trying to avoid other people making errors that are already known to exist - for example welding at 90 degrees to a structure is something that should be avoided if at all possible - you obviously didn't see my comments that way. For the past 20 years I've worked on all sorts of large mining equipment major structural repairs. I was the guy in our technical organization charged with developing and documenting repair procedures where none existed previously, even from the manufacturer. If you PM me an e-mail address I'll gladly fill your inbox with 100's of reports with photos of major structural issues that our technical dept tackled. To our organization the D11 track frame bore rebuild would have actually been classed as a "minor" job, but how a job is defined obviously depends on the amount of resources you have to play with. We had 10,000+ sq.ft. of workshop space and an annual budget that would make your eyes water. Suffice it to say it had 7 zeros at the end of it .......
Anything is better than a slack old bush, Steve is doing it as good as he can with what he has, plus thats a neat bit of MMA (its what I use), I would have thought it might have been easier to set up that bore head with the frame on its side but what do I know?? its how steve does it, its a great job well done, the welding method is not as important as the cutting of the new surface, by the looks of things the welding is to a very high standard, so steve its good **** from me. p.s. my annual budget hardly goes into 2 zero's but I always get em running.
I'm sorry but I don't agree. Unless the building up with weld is done right there are high odds that the structure is going to fail eventually, however pretty the final job might look. If I had a tenner for every cracked or failed structure or casting I've seen where someone had made half-assed weld repair on it that triggered the start of a crack that led to the final failure I could have retired years ago. I have some photos somewhere of the A Pin of a 994 Lift Arm assembly (main Lift Arm to front chassis pin) that was built up by MMA in exactly the same way as this pivot shaft bush bore. About 3 months later it broke without warning right through from inside to outside with a high-cycle fatigue crack that had as it's initiation point either a small slag inclusion or a lack of penetration (so long ago now I can't remember which one it was) in one of the transverse weld beads used to build up the bore. That failure cost the customer upwards of $200k for a new Lift Arm Assembly plus probably close to $50k for us to nail the broken one back together. He needed a spare one anyway, he had 6 machines. Needless to say we got all his frame reboring work after that instead of him getting "Joe Blow's Mobile Machining Services" in to do the job. Failures like that concentrate the mind wonderfully ........ Again I will stress I'm not trying to criticise what Steve's done in his repair that started off this thread, just throwing out ideas and options based on years of experience that might help someone else do even better in the future. :Banghead:Banghead
Nige and gaven if im not mistaken the oversized bushings your reffering to are oversized to the inside diameter of the bushing. I have seen them in differnt sizes but always to the id for a reworked pivotshaft. Theres been a lot of 8s 9s 10s 11s welded even by cat i know stowers field boring guys. They used to weld them just like i do now they have borewelders but sometimes still handweld. Soft arc but good penetration are a must in a good borebuildup. I think borewelders are great but i Know some people using them that cant even weld. They make pretty automated borewelds that are cold sleeves that come out. ive had 0 failure rate in 15 years of repairing bores so its works for me. Cat has welded the same way as me for many mant years. I think the shape of the track frame suggest tha it carries torsional loads from many differnt directions. If not it coulld look like maby an ibeam so sometimes the advantage has a disadvantage. Please sent special sehs8972 but till then i have to fill the void with a solid mass type substance Steve
welds dont to forget to postheat
dint forget safety on working
Do these wear through lack of oil or old age and what they do. Cheers
Looks good Steve. What's important is getting the job and it sure looks like you're doing that. I've had many dealer mechanics or those from large shops tell me that I couldn't do something or what I was doing was all wrong but in the end it worked, the problem was solved and it didn't come back. Knowing what you're doing is definately necessary but we all have our own ideas as to what that is. Keep up the good work.
Nige, you talk of a pin being built up with weld, the pin failing resulting in damage to a loader frame??, I am looking at a big hole in a frame, I dont think its on the same scale, I tend to think I would be happy to repair the frame as steve has done without worry, on the bore /cutting thing, it would be best to get this detail as good as can be, as any off centre or incorrect angle is going to cause big trouble very fast, this is my thoughts only.
You misunderstand me, reading my post above I didn't make it clear. It was the A Pin bore on a Lift Arm that was built up with weld in just the same way as this pivot shaft bore was built up, then the Lift Arm failed right through the bore. Root cause of failure was the welding. I'll see if I can find the pictures, then it'll be clear.
Ninge i have to be honest with you. You can show that picture but it wouldnt prove anything. I have seen a boom on a 375 michigan that was autto welded break in the bore. Anyone in or around lineboring knows what a york lineboring machine is right. Go to thier website and watch thier 414 video it shows more bores built up like i did it than auto period. The first sentance i ever saw from you was i would have used top secret 2050891 bushing. Why its for a repaired pivot shaft this machine has a new pivot shaft. If they had let the x number of dollar company guy do it the roller frame wouldnt even fit back on the machine oops rollerframe press scgr35021. To quit messing around though welding does have stress risers i feel without even a pinhole and with machining i have helped that alot. You described never to weld 90 degrees to the work im the one welding with the BORE and 90d to the face. Spiral welding would 90d to the bore. Its like talking to a engineer wo on paper is correct but in the real world it dosent work they have big bank accounts also. I have read your post and advice on here and i wouldnt pay you to be a mechinic on my job. In all the 450226 top secret bushing stuff you never mention post heating which is as important as preheating. Maby what tempature you preheat or not annealing the frame so its soft in the welded area is what you need to be concerned with.
Looks good to me. We weld up bores in the same way, we also have a bortech and weld them up in one continuous pass. It all depends on who is doing it and what size the bores are. Never had a failure of the parent metal cracking. We have done D11 side frames, 992 booms and frames and everything else you can think of.
swampman,tctractors,excavator,lee-online Thanks for the comments. Lee i worked for chloe ridge coal and 92'c were it in my day long time ago. Somewhere on this site i have some pictures of a 92d i was boring the mouses ear. I have a 990 boom to start on when i get caught up. The bortech seems to me the best looking borewelder out there i would like to have one ive thought about the dozer model well see. I have done a lot of talking to heat treaters of larg castings and many have told me that stick is a prefered method but it isnt very productive. I do like being able to controll the welding and actually see the puddle flow into the parent metal and bead i pause when fuesing to each and know. Lee i see you can acess differnt monitors i do some older excavators with grey monitor 0e323a code b and c but cat tells me that on the d on up i cant acess like that anymore is this true. Thanks Steve
Good job Steve, I have welded bores like this before I had a bore welder and that was 14 years ago. No failures yet. Good work.
Tom thanks the finished frame is in another post. I have looked at your work and its unreal . Are you the tom V in boa bore welder video. Thanks Steve
Thanks for the compliment Steve, and yes that is me in the bore repair video.
First post here This is my first post here. I was sent a link to this thread by a friend. It has interest to me as I was line boring a 10R pivot shaft bore at the time. I've been line boring heavy equipment since 1988 so I might hang around and pick up a few ideas and tips and maybe I have some stuff I can share
Hello ray id like to see some of your work Steve
I have heaps of pics but I don't think I can post pics here yet Here's a link to a website I have but it hasn't been updated for years. http://members.iinet.net.au/~plb/jobs.htm A few pics there.
Ray you do alot of boring that is a nice set up. I used to bore more when i worked for a small strip mine about 15 years ago the owner had a hyd bar drive but we still had to build the bores by hand. Now i just work with a small service truck doing maby 70% mechinical 30% welding 10% boring. So im no pro lineborer its just something i do from time to time. i actually built the old rig in the pictures because a company in town had a 355 komatsu they had let the sprrocket segments run loose and messing up the hubs. With labor and parts at 10 grand a side at komatsu he ask me to repair it thats how she was born. a big drill tacked to the roller frame i have a stub bar with for jt drill bits. I drilled close then took a reamer and repaired the holes. Having to be larger i used segment bolts from d11 or something in the repair. The machine was sold years later and somewhere in this world some dude is scratching his head thinking *** when he wants change segments. I just dont get enough to warrent buying like a york but i have been looking at building a new one. Send more pics heres a few more of my old stuff
I like your pics One of the necessities of onsite machining is being able to improvise and it looks as though you can do that. My gear is manufactured locally by Hofmann Engineering.We can bore from around 11/2 inch to around 36 and face out to those diameters as well.I used to employ men and had a few rigs but I've scaled down and now there's only me. I'm trying to scale back more but my clients have other ideas.The contract miner where I'm working at the moment have 2 D10R's to do(all bores,rippers etc)a couple of 785 trucks,a WA1200 bucket,Cat 994 loader frame,levers bucket and a heap of lathe and milling work.
Ray the jobs you do are awsome. You could put the jobs i do in the bores of what you do. Im going to have to pic your brain now. Aprox what rpm or sfpm would you run on a 10.375 bore roughing and finish. Thanks Steve
Probably around 120 to 150 rpm. A welded bore I would take to size with 3 cuts,the last one around 10 thou for a finisher.I use carbide inserts. I like to put in just enough weld.A 100 thou in the diameter is plenty.
Steve your job looks like some i have seen some one know what there doing
Thanks