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Annealing 4130 after work hardening

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  • #16
    I tried a few other searches. The only reference of small pulleys is to use them for turns of less than 90 degrees. Bigger pulleys are definitely preferred on an absolute basis for less friction (and less wear) on the cable and pulley.

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    • #17
      I did get in touch with Bob and he said the smaller pulleys are OK. The ones used next to the stick are a little bigger but has a 1/4 bore instead of 5/16. He did not recommend using a bushing on the mount if you wanted to use that one, but recommended welding the hole and re-drilling.

      I made new mounts for the 3" pulleys. As long as they work I think that is what I am going with.

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      • #18
        Cro-Mo does definitely work harden. bend it about half way---- then heat it red hot with oxy----uniformly and slowly till dull red. then back the torch off very slowly to drop the temp slowly. an alternate method--- have a box of powdered lime standing by. Heat red hot uniformly--- as quickly as possible plunge the red hot part down into the center of the lime and cover it up. The lime is in insulator that forces the part to cool very slowly. leave it for about an hour. Good for annealing.
        once annealed it will bend much easier the rest of the way. You can anneal again when done---- maybe less hot if you like. Inspect for cracks.
        Grind and polish the edges so there are no nicks or pits. You can do dye-penetrant if its a critical part. The "critical" temp for steel is the point where it becomes non-magnetic. Thats medium red. But it still anneals quite a bit at dull red too. depending how hard you worked it . The more carbon in the alloy the more it work hardens. Welds in clusters and thick parts are often annealed after welding and sometimes pre-heated before welding to make temp change more gradual in time. less temp. differential across the part that way. also pre-heated in cold weather. Thats my understanding-----

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