Announcement

Collapse
No announcement yet.

Crankshaft repair. Truly amazing.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Originally posted by wierdscience View Post



    Probably shouldn't mention the modern large frame diesel cranks that are assembled by welding together forged sections right in the middle of the journals either huh?
    No you probably shouldn't but glad you did, do not compare something that was engineered and designed with all kinds of overkill to be able to do what your describing --- it's not even in the same ballpark...

    Comment


    • I watched the video twice, that guy was amazing to watch. Obviously not his first rodeo. I took the time to read a bunch of the comments of the video and the one that I think was the best said was, "Note how this break is on the end away from the load end? Maybe the harmonic balancer was bad, or maybe that cylinder was hydro locked. In any case, I would tag the crankshaft “for 5 cylinder use only". My guess is all those cranks we're probably from engines for industrial use.
      Last edited by lugnut; 12-29-2021, 07:48 PM.
      _____________________________________________

      I would rather have tools that I never use, than not have a tool I need.
      Oregon Coast

      Comment


      • The Title of the OP is "Crankshaft repair. Truly amazing" and I do believe it's something we all can agree on...

        Comment


        • Anyone still wondering why this forum doesn't attract many new contributors?

          Comment


          • Originally posted by tomato coupe View Post
            Anyone still wondering why this forum doesn't attract many new contributors?
            Nahhh -- it's obvious when you see posts about someone asking for snow tire info and you got guys telling them they need to scrap that Idea and just get a different vehicle...

            Comment


            • Originally posted by tomato coupe View Post
              Anyone still wondering why this forum doesn't attract many new contributors?
              They are all watching Youtube
              I just need one more tool,just one!

              Comment


              • Failure happens.

                This is some kind if roller shaft from a paperboard manufacturer, they brought it in earlier this year. The failure appears to have began at the bottom of the keyway.

                Can you fix this?

                Yes.

                How?

                Make a new one, so I did.

                Comment


                • The idea that the procedure in the video isn't highly refined is pretty funny. I intend to adopt the indicator stand on the heavy plate that just sits on the ways.

                  His procedures are so highly refined they've achieved simplicity.

                  Your request is granted. You're out.

                  Comment


                  • Originally posted by tomato coupe View Post
                    Anyone still wondering why this forum doesn't attract many new contributors?
                    Nope.

                    I'm new, brand new, and the things I've heard about this forum are clearly true.

                    Speaking as the new guy, the best reason to participate in this forum is because it's not quite as bad as Practical Machinist.

                    Comment


                    • Originally posted by wierdscience View Post

                      They are all watching Youtube
                      Yeah - some of us were lol and as you will soon find out for some of us - it sucks to learn,,,

                      I believe this quick vid is just about laser cladding and not even trying to glue something back together, something about the common crank material of 42CrMo4 having a 60% drop in fatigue strength rating after welding...

                      Now top that concern onto the fact like I stated earlier of the two different materials coming together and stopping on a dime and all the havoc that creates DIRECTLY at the source of CONNECTION where it will soon fail AGAIN...

                      You guys --- My main stance is that a weld repair on same size journal will not be as good as new material, that's a given fact--- that's even and actually especially if the weld material is way stronger in every way ---- again - this is not rocket science - it's welding and metallurgy 101 --- and yet you can't handle that --- bring the finest crank engineer into the mix and have him dispute this with me and then sit back and watch me give him the spanking of his life --- im not talking about running crosswebs of weld into the cranks side webbing --- im talking about habib's "fix" of a weld beam down the middle of a journal

                      His crank is not somehow magically stronger than a new one - his crank is not even as strong as a new one - his crank is actually quite a bit weaker than a new one --- but geeze - polish a turd and everyone on here is drooling over it -- that's fine too but as i stated a long time ago - COUNT ME OUT!

                      again - give credit to people doing what they have to do to get by --- but try not to get carried away as this is some kind of god like repair of refinement - the guys a hack and a damn good one but a hack....

                      BTW -vids just over two minutes long - have the decency to watch it cuz i already wasted 45 minutes of my time watching habib...


                      https://youtu.be/BA3BskhJD9k

                      Comment


                      • Originally posted by Bented View Post
                        Failure happens.

                        This is some kind if roller shaft from a paperboard manufacturer, they brought it in earlier this year. The failure appears to have began at the bottom of the keyway.

                        Can you fix this?

                        Yes.

                        How?

                        Make a new one, so I did.

                        [
                        Once again Bented you'v wondered into the wrong post, This OP is not about doing things right.... it's about hacking it together to hold "for a bit"

                        you should have welded and weakened the shaft material in other areas with excessive heat and also created variances in it's material composition in the process right at the site of "re-glue"... this is about failure not success...



                        try to pay more attention next time? Thanks buddy...

                        Comment


                        • Originally posted by A.K. Boomer View Post

                          His crank is not somehow magically stronger than a new one ...
                          Did someone make that claim?

                          Straw man tactic.
                          Last edited by The Artful Bodger; 12-29-2021, 11:49 PM.

                          Comment


                          • Originally posted by The Artful Bodger View Post
                            Did someone make that claim?

                            Straw man tactic.
                            Sometimes you have to show the other extreme, there does seem to be allot of folk on here who think it's "good as new" and it's not... that's the only thing im trying to get across - it's not - it cannot be - it's compromised... that's all no big whoop, accept that fact and I don't have an issue - argue it with me and I will set things straight...


                            Comment


                            • Originally posted by A.K. Boomer View Post

                              Yeah - some of us were lol and as you will soon find out for some of us - it sucks to learn,,,

                              I believe this quick vid is just about laser cladding and not even trying to glue something back together, something about the common crank material of 42CrMo4 having a 60% drop in fatigue strength rating after welding...

                              Now top that concern onto the fact like I stated earlier of the two different materials coming together and stopping on a dime and all the havoc that creates DIRECTLY at the source of CONNECTION where it will soon fail AGAIN...

                              You guys --- My main stance is that a weld repair on same size journal will not be as good as new material, that's a given fact--- that's even and actually especially if the weld material is way stronger in every way ---- again - this is not rocket science - it's welding and metallurgy 101 --- and yet you can't handle that --- bring the finest crank engineer into the mix and have him dispute this with me and then sit back and watch me give him the spanking of his life --- im not talking about running crosswebs of weld into the cranks side webbing --- im talking about habib's "fix" of a weld beam down the middle of a journal

                              His crank is not somehow magically stronger than a new one - his crank is not even as strong as a new one - his crank is actually quite a bit weaker than a new one --- but geeze - polish a turd and everyone on here is drooling over it -- that's fine too but as i stated a long time ago - COUNT ME OUT!

                              again - give credit to people doing what they have to do to get by --- but try not to get carried away as this is some kind of god like repair of refinement - the guys a hack and a damn good one but a hack....

                              BTW -vids just over two minutes long - have the decency to watch it cuz i already wasted 45 minutes of my time watching habib...


                              https://youtu.be/BA3BskhJD9k
                              Not that it matters, but this whole disscusion has nothing to do with laser cladding, that is a completely different process for a different purpose. In any rate the video you posted states correctly that the highest area of stress are the fillets. The Pakistani welded the two halves of his crank in the center of the journal and then added metal to increase the size of the fillets. We know from the video that the crank was not heat treated originally and even if it was anything as exotic as 4140, in the annealed state 4140 is 60,000# tensile and 70xx weld filler is 82,670# tensile. Given the quality of the weld shown he's gonna be close to parity.

                              Now I know you are insisting that welding a crank is a "hick" move, reserved for third world back waters. However the existience, commonality and common use of the technique combined with the existience of purpose built machinery for the task would counter that argument. How about welding up ALL the journals on a crank?

                              https://www.youtube.com/watch?v=EM-Kf20THxo

                              Or maybe just one?

                              https://www.youtube.com/watch?v=UYGzVzpWrw4
                              I just need one more tool,just one!

                              Comment


                              • Originally posted by wierdscience View Post

                                Not that it matters, but this whole disscusion has nothing to do with laser cladding, that is a completely different process for a different purpose.
                                Actually it does matter because they also stated welding and also why it really matters is this is beyond just welding - it's welding two pieces together,,, actually laser cladding is about as minimally invasive in comparison to the two other examples... of course the welding of two pieces together the extreme one...




                                In any rate the video you posted states correctly that the highest area of stress are the fillets. The Pakistani welded the two halves of his crank in the center of the journal and then added metal to increase the size of the fillets.

                                I believe you conveniently skipped this part;

                                "The highest torsional stresses are in addition to the web fillets AT THE JOURNAL AND CRANK PIN OIL BORES"

                                You know where that's at right? yup right were habib was putting his silly putty on -- remember the other guy he passed the crank too? the master oil bore driller - after the hole got plugged with the putty???



                                We know from the video that the crank was not heat treated originally and even if it was anything as exotic as 4140, in the annealed state 4140 is 60,000# tensile and 70xx weld filler is 82,670# tensile. Given the quality of the weld shown he's gonna be close to parity.
                                lot's of speculations - lot's of assumptions --- but here's a total fact - he could be spot on with his rod choice and the vast difference in heat and cooling with just it will throw everything out of balance as far as hardness of the original material and the weld

                                any deviance of the weld material in either strength or hardness is a weaker crank as a unit, it will fail at where the crank material meets the weld....

                                keep in mind their not even going into harmonics/vibrations and frequencies let alone compounding the effects at certain rpm ranges


                                Now I know you are insisting that welding a crank is a "hick" move, reserved for third world back waters. However the existience, commonality and common use of the technique combined with the existience of purpose built machinery for the task would counter that argument. How about welding up ALL the journals on a crank?

                                https://www.youtube.com/watch?v=EM-Kf20THxo

                                Or maybe just one?

                                https://www.youtube.com/watch?v=UYGzVzpWrw4

                                Guess you missed my post on the rare V/4 english built saab engine I had to have a journal built up and done? it's hack - it was a compact as all hell crank - I built it up - it lived, was it as strong as new --- No fuquing way - that's my point - was glad the POS held together long enough to move it...


                                So - just to clarify --- hack can be good, just depends on your situation ------- but not going to say it again - habibs crank is compromised in comparison to a original one piece, that's fact --- don't shoot the messenger boy... just telling things like they are....

                                Comment

                                Working...
                                X