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A new attempt at making piston rings

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  • Gentlemen I have been involved in this small engine building hobby for about 12 or 13 years. The only thing which I have consistently failed in is making cast iron piston rings that work. I think the time has come for me to learn this arcane skill, and I am doing exactly what Trimble suggests, buying the same tools Trimble used. I am breaking the rings with the same implement that Trimble suggests, using the same India stone Trimble suggests, and trying religiously to take all of the same steps that Trimble took.
    Brian Rupnow
    Design engineer
    Barrie, Ontario, Canada

    Comment


    • Originally posted by brian Rupnow View Post
      ........................................... I am doing exactly what Trimble suggests, buying the same tools Trimble used. I am breaking the rings with the same implement that Trimble suggests, using the same India stone Trimble suggests, and trying religiously to take all of the same steps that Trimble took.
      Very good plan. You have a "recipe" that produces good results, and are planning to follow it. More than reasonable, as I see it.


      Hey, if there is a known recipe, it must be easy enough, so changing some things to make it "easier" in your particular shop can't be a problem, right? You are doing the "exact same thing", just a different way! What could go wrong?
      2730

      Keep eye on ball.
      Hashim Khan

      Everything not impossible is compulsory

      Comment


      • Many many have used his method with success, now its your turn. I again mention having a suitable cast iron alloy, never seen a response, its either unknown or secret.

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        • Today I picked up my 1 mm (0.039"0 lathe tool from Can-cut, a local sharpening service. Yes, it does have a bit of side relief on it. He made it using a surface grinder. ---Yes, I paid $75 for it, but this is still only about 1/2 of what I would pay for a carbide and toolholder out of USA. Next step will be to machine a holder for this tool and see exactly what width of cut it actually makes in a 1" diameter piece of aluminum round stock.----And yes, I agree with the sentiment "More money than brains".
          Brian Rupnow
          Design engineer
          Barrie, Ontario, Canada

          Comment


          • Sparky---Just for the record, yes, this is fine grained grey cast iron, of the type used for making rings.
            Brian Rupnow
            Design engineer
            Barrie, Ontario, Canada

            Comment


            • Originally posted by brian Rupnow View Post
              Sparky---Just for the record, yes, this is fine grained grey cast iron, of the type used for making rings.
              As I suspected, its just generic fine grained? ( or said to be fine grained) Like all metals, there is numbers, tradenames and identifiers, you know that. Saying fine grained is like saying carbon steel or billet aluminum, pretty meaningless. Odds of success are pretty low if the material isn't suitable. How many good functioning rings have you made to be able to identify "the type used for making rings" ?????

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              • Something very fishy is going on, and I don't know what. My new tool is setting at exactly the correct height (centerline of spindle), perfectly square to the long axis of the lathe, and the tool is ground perfectly square across the end. I made three plunge cuts, using the cross slide to advance the tool into the cut, with lots of wd40 as lubricant. My new tool is set up with very little unsupported "stick out". Then I cut the aluminum round blank on my bandsaw to expose a cross-section of the cut. All of these cuts look crooked to me. I don't think there is any way that a ring can seal against either side of the plunge cut. My cross slide is set at 90 degrees to the long axis of the lathe. Does anyone have an explanation of what may be going on here?
                Brian Rupnow
                Design engineer
                Barrie, Ontario, Canada

                Comment


                • That is weird. Just a guess, maybe the aluminum isn't clearing out of the cut properly, getting wedged in there and bending the wall over?
                  I wonder if there is such a thing as "free cutting" aluminum?
                  I wonder what the cross-section would look like if you did the same cut on 12L14 steel, or cast iron.
                  25 miles north of Buffalo NY, USA

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                  • What you want I believe is- Nodular Iron or Ductile Iron or Meehanite S 60 - which is called Ductliron┬«, a registered Meehanite trade-name for a group of high carbon ferrous materials containing graphite in the form of nodules or spheroids and which is also known as ductile iron and nodular iron.

                    I was taught to only use Meehanite iron for rings , so I may be prejudiced.


                    You may wish to see this about Federal-Mogul a world wide manufacturer of Piston Rings

                    Note , when you cast the rings, you set up circular grain structures and i have seen FM ring castings only 1 inch in diameter

                    Rich.



                    https://www.foundrymag.com/melt-pour...olding-process

                    Green Bay, WI

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                    • Cancel that last question.--Investigation shows that tool was setting crooked in holder. I will make a better tool holder and try this again.
                      Brian Rupnow
                      Design engineer
                      Barrie, Ontario, Canada

                      Comment


                      • Never mind.... I see your explanation.
                        2730

                        Keep eye on ball.
                        Hashim Khan

                        Everything not impossible is compulsory

                        Comment


                        • Ah, OK. Yeah, I've had a few like that too :/
                          25 miles north of Buffalo NY, USA

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                          • Okay---Proper tool holder gives perfect grooves. The grooves measure 0.040" wide with my Vernier caliper, so I'd say it's good. The grooves appear at a proper 90 degrees to long axis of part. I'm happy with the new tool.

                            Brian Rupnow
                            Design engineer
                            Barrie, Ontario, Canada

                            Comment


                            • Yeah you've got to watch out for those v-groove holders, they can bite you in the ass if you aren't paying attention.

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                              • Rookie move dude!

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