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Cracked Boom Pictures! Suggestions?
- Thread starter alaskaforby4
- Start date
ddigger
Senior Member
well done
Scrub Puller
Senior Member
Yair . . . yank132 Thanks for the detailed post.
For this old bush mechanic some things are slipping into place. As mentioned up thread I see things break from the OEM and I rock up with the old Lincoln with a couple of packets of low hydrogen sitting on the exhaust manifold of the Perkins and I gouge it it out and weld it . . . no plates or anything and it never breaks again.
I have no confidence in any weld made by a wire feeder on anything over three eighth . . . might look okay on the surface but so do some bad women.
With the inverter power sources for TIG though I reckon they are magic. . . especialy for alluminium.
Any comment?
Cheers.
For this old bush mechanic some things are slipping into place. As mentioned up thread I see things break from the OEM and I rock up with the old Lincoln with a couple of packets of low hydrogen sitting on the exhaust manifold of the Perkins and I gouge it it out and weld it . . . no plates or anything and it never breaks again.
I have no confidence in any weld made by a wire feeder on anything over three eighth . . . might look okay on the surface but so do some bad women.
With the inverter power sources for TIG though I reckon they are magic. . . especialy for alluminium.
Any comment?
Cheers.
OldandWorn
Senior Member
Good looking repair alaskaforby4. I would also like to comment on your nice shop and well maintained looking excavator. Is the red thing in the corner a press?
Nige
Senior Member
I think that repair is going to solve the problem, however I'm going to be picky and opine that maybe the curves should have been "tailed out" even more pronounced than they have been and maybe that the welding on the curves should have stopped possibly an inch before the end of the plate rather than run right to the end (and into the high stress areas of the top/bottom plates) as they have been. But as I say that's me being picky.
I like the fact that the repair has been cleaned up and painted afterwards. Proves my theory about "if it looks professional, it's likely to be professional"
I like the fact that the repair has been cleaned up and painted afterwards. Proves my theory about "if it looks professional, it's likely to be professional"
alaskaforby4
Senior Member
Thanks! Yes its a 50ton press, she is an antique but it works great!
icestationzebra
Senior Member
The patch looks pretty good. The rosette welds are a good touch. The only thing to watch it that new cracks don't start forming at the corners of your patch plates, especially since they end in line with the stick cylinder anchor. I think you will be OK, but it would have been cheap insurance to run the corners out farther.
ISZ
ISZ
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robin yates uk
Senior Member
that repair will outlast the pyramids, good luck
Nige
Senior Member
Glad that it wasn't just me who was thinking about curving the doubler plate more & tailing the welds out. I always believed that you need to "curve & tail" the doubler plate out so much that the weld on it is almost running parallel to and about 1" away from the OEM weld at the point at which it runs off the plate. The plug welds in the holes on the repair are perfect so that the stress created by welding the fillet welds at the edges of the plate do not tend to pull the centre of the plate up away from the structure.
Please don't take what I have written above as a criticism. I reckon that repair will outlast the machine. :drinkup
TozziWelding
Well-Known Member
Looks good, but I would have rounded the corners on the patch, cracks propagate at sharp corners.
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xcmark
Senior Member
I think if I was going to own this machine for a long time I would plate the other side of the boom the exact same way , chances are if one side is stress cracked the other is not far behind.
well done.
CRAFT
Senior Member
If you go back and look at all the pics he submitted you'll see that he already did : Post #1- shows that the original crack was on the right side of the boom .... Post #60- (1st pic) shows the right side preped for the new plate and a repair weld ...... and the last pics just happened to show the repair completed on the left side of the boom .... just thought i'd bring that to your attention .... :drinkup cheers
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Nige
Senior Member
Sorry I don't agree. IMO the doubler plate needs to be curved outward like this illustration. Also the doubler plate need to be approximately 30mm (1-1/4") narrower than the structure - 15mm on each side. The welds on the curved ends of the doubler plate should either stop about 20mm (3/4") before the end of the plate, OR be run out 50-75mm (2-3") past the end of the plate terminating parallel to the existing structural welds and approximately 15mm away from them
Bluetop Man
Senior Member
I've noticed this technique is a prevalent practice in the fabrication of CAT equipment with welded attachments.
I don't have a clue as to how the off brand manufacturers do it...:beatsme
icestationzebra
Senior Member
Nige - If you are referencing the picture you attached, the doubler plate is narrower so that the weld beads line up with the side plates to get the most strength. Plus if you run too close to the edge you risk a burn out which will create a big stress riser.
"that repair will outlast the pyramids"
This repair looks pretty solid, but one thing that I learned early on is that adding metal is not always the answer. Often you just move the problem somewhere else! And the welding details (filler, preheat, fillet size, post treatment grinding/peening, etc.) are just as important. Every place in a weldment where you have a change in shape or thickness is an increased risk of cracking. If you want proof just compare the shape of almost any machine today vs. it's 1970's counterpart. Even though it is more expensive you now see mostly radiused or tapered parts vs. the old boxy shapes.
Anyway, just tryin' to pass along some wisdom. Hopefully it helps someone else.
ISZ
John C.
Senior Member
Gentlemen,
This is a 490 Deere which is equivalent to a PC120 or EX120. It's at least fifteen years old. The weld repair that was accomplished will certainly outlast what is left of the machine.
This is a 490 Deere which is equivalent to a PC120 or EX120. It's at least fifteen years old. The weld repair that was accomplished will certainly outlast what is left of the machine.
CRAFT
Senior Member
............... " EXACTLY " ..... lmfao
hvy 1ton
Senior Member
The plate would have been better if the corners were longer like Nige and ISZ said. I would have laid down a coat of weld-thro primer, l but that's me being paranoid about rust. Terminating the weld before or after the end of the plate is a new one to me tho, any more insight on that one guys? I'd be very surprised if your repair fails, just some constructive criticism if you have to do again. Although, dollars to donuts it'll be on a different machine.