Announcement

Collapse
No announcement yet.

Pulley repair

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

  • #16
    Originally posted by Illinoyance View Post
    It is possible to build up the flange using cast iron rod with an ocy/acy torch and the proper flux. Afterwards machine away the over-build. I learned recently that cast iron rod can be used with TIG and no flux but have not tried it myself.
    True enough, and I've done it -- but man what a PITA! Cast iron is *dirty* !! That's why I prefer to "butter" the surface of the broken part with a few layers of pure nickel rod. Makes your life *so* much easier in the future. Allows you to finish the job with regular rod and has the same strength as steel with none of the drawbacks of trying to put steel rod directly with the cast iron. I'm forever grateful for those metallurgy classes I had during training....
    25 miles north of Buffalo NY, USA

    Comment


    • #17
      I would either braze it up and re-machine, or part that groove off. Either way, balance won't be critical.
      I just need one more tool,just one!

      Comment


      • #18
        Originally posted by wierdscience View Post
        I would either braze it up and re-machine, or part that groove off. Either way, balance won't be critical.
        X2 I would be far more inclined to part the groove off. Its just far less work than repairing it, and it would be very unlikely to notice the loss.
        25 miles north of Buffalo NY, USA

        Comment


        • #19
          My three pennyworth, similar to Ringo’s suggestion I would machine off the damaged flange then make “replacement “ from mild steel but use a shrink fit to hold it in place. Allow say .002” interference per 1.0” of diameter, heat he replacement part to blue and drop it on. In the past I have converted lots of flat belt pulleys to V belt by this method and never a problem, however I was always making a complete V not half a V.
          John
          Knowledge withheld is knowledge lost

          Comment


          • #20
            Two days ago I got back to it. I opted to us nickel rods. I had bought a dented can of them. Most of the rods are fine some have the flux missing in spots and one or two went right into the scrap bucket.

            To help others this is what I did. I grounded the missing area to clean cast iron if there is such a thing. That warmed it up to were I could not touch it. I then ran one bead down in the bottom staying away from the thin ends of the grind. The first bead had a lot of porosity in the bead. I ground that out to clean nickel and back to cast in one or two places and ran another bead of nickel. I had one more spot that had a bubble so I ground that out too. After that I would run a bead walk away for a minute or two and then run another bead. When I filled most of it I let it cool down for about 5 minutes and then just tapped the thinner parts to get some nickel in that area. I then just added till I thought it we high and wide enough. When I was done I put it in a bucket full of sand and let it cool.

            Today I put it on the lathe and found out one important thing. I do not like interrupted cuts. Wow Small cuts and take your time. Nickel is kind of gummy to cut.

            Click image for larger version

Name:	IMG_0023.JPG
Views:	176
Size:	1.06 MB
ID:	1880020Click image for larger version

Name:	IMG_0026.JPG
Views:	165
Size:	1.30 MB
ID:	1880021Click image for larger version

Name:	IMG_0029.JPG
Views:	170
Size:	1.14 MB
ID:	1880022

            Comment


            • #21
              Click image for larger version

Name:	IMG_0033.JPG
Views:	175
Size:	1.12 MB
ID:	1880024Click image for larger version

Name:	IMG_0035.JPG
Views:	170
Size:	1.21 MB
ID:	1880025Click image for larger version

Name:	IMG_0040.JPG
Views:	171
Size:	1.23 MB
ID:	1880026

              Comment


              • #22
                Click image for larger version  Name:	IMG_0042.JPG Views:	0 Size:	1.55 MB ID:	1880028

                There is still some ruff spots in the groove that I may or may not add weld to. I was more worried about the balance. But I think this will resolve that for me.

                The only real training I have had to be a machinist was in high school 40 years ago. Thank you adding to my education.
                Last edited by outlawspeeder; 06-09-2020, 01:05 AM.

                Comment


                • #23
                  Originally posted by outlawspeeder View Post
                  Click image for larger version Name:	IMG_0042.JPG Views:	0 Size:	1.55 MB ID:	1880028

                  There is still some ruff spots in the groove that I may or may not add weld to. I was more worried about the balance. But I think this will resolve that for me.

                  The only real training I have had to be a machinist was in high school 40 years ago. Thank you adding to my education.
                  Instead of welding would putting in some JB Weld or similar and then machining it smooth work? With the weld backing it for strength is should hold up well.

                  Comment


                  • #24
                    That pulley reminds me of the drive that Robinson helicopters have, the R66 puts 224hp through pulleys like that, how much power does your K & T use?

                    Comment


                    • #25
                      Hey that looks pretty good.
                      You say that you pre-heated to being too hot to touch.
                      Well, preheat with cast iron is really critical.
                      Slow cool down is just as critical.
                      It is so important, I thought it was worth mentioning.
                      I would have to look up the temperature, but it is like
                      400 or 600 degrees. Best to use a wax temp stick to
                      verify. Lacking one, I would heat to a very dull red
                      that is barely noticeable in regular light. Then cool
                      under an insulation blanket.
                      But really, I would not have worried about one sheve
                      being broken and effecting balance. But I know that
                      all you home shop gerbils have OCD really bad, so
                      I get it.

                      -Doozer
                      DZER

                      Comment


                      • #26
                        Here is something most are ignoring the flange you want him to cut off contains the balancing holes, cut it off, it's out of balance.
                        second I have like 3 or 4 pulleys on my lathe, bought a matched set of replacement belts, a few years later they are not all as tight, only two pulling, not so good, cut one row off 4 leaves 3 if one belt slacks more than the others, good luck with heavy cuts.. .. but hey it's fixed now, all belts can be in place..

                        Comment


                        • #27
                          Now you will have to find a source of 4 matched belts, unless that is an idler.
                          The out of balance forces would indeed be noticeable at 5000 rpm and upwards.
                          Also, the vees will have to be matched precisely for the matched belts to transmit equal power.
                          I wonder what would happen if the weld broke?

                          OOO, I forgot the OCD that Doozer mentioned, I'm sure it will all be ok.
                          Last edited by old mart; 06-09-2020, 04:35 PM.

                          Comment


                          • #28
                            FFS it'll be just fine you OCD freaks. I've done plenty of repairs like that on the job no less.

                            1) balance is a good point. A fraction of an ounce due to using different materials isn't going to be noticeable on a motor that size, with that much rotating mass, coupled by multiple rubber belts. So, no, not really.

                            2) Preheat/post-heat not really that critical on a "fill it in" job as opposed to a "joining two pieces" job. Why? because the "fill it in" isn't constrained in any of the directions that it can shrink when it cools. Worst case scenario, his bore is half a thou out of round. The ductility of nickel is your friend. Preheat and slow cool is generally a good idea on cast iron, but not always needed.

                            3) I *do* hope he re-machines it all over smooth to avoid chewing up belts, and to eliminate minor imperfections. Preferrable all in one setup. Mainly for roundness and concentricity.
                            25 miles north of Buffalo NY, USA

                            Comment


                            • #29
                              [QUOTE=old mart;n1880214]Now you will have to find a source of 4 matched belts, unless that is an idler.


                              Good luck finding matched belts these days unless you order a Banded belts,I got 3 330" B belts that were supposed to matched one had slack hanging down 3" when installed.Returned all 3 to Belt Supplier and ended up at Warehouse where they dug through all of them to find 3 with the same BATCH # when manufactured.

                              Comment


                              • #30
                                [QUOTE=Tundra Twin Track;n1880290]
                                Originally posted by old mart View Post
                                Now you will have to find a source of 4 matched belts, unless that is an idler.


                                Good luck finding matched belts these days unless you order a Banded belts,I got 3 330" B belts that were supposed to matched one had slack hanging down 3" when installed.Returned all 3 to Belt Supplier and ended up at Warehouse where they dug through all of them to find 3 with the same BATCH # when manufactured.
                                I don't know what the proper terminology is, but my last employer had a similar situation. Belt was going onto a 50-hp motor on a VFD to spin a 30" dia steel plate that weighed ~250lbs. The supplier informed us that Gates Rubber makes a type of belt where all 4 of them are joined into one really wide belt. But I forgot the trade name for it. I'll never forget bench-pressing that sheave though... (vertical application)
                                25 miles north of Buffalo NY, USA

                                Comment

                                Working...
                                X