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  • How flexible is brass

    I have a 1.5" steel round bar that I would like to dress up with a decorative brass ring, maybe 1/8" wide or less. I'm thinking I could cut a groove in the bar then make a split brass ring to 'snap' in.

    Questions are...

    How well does brass flex and does it have any spring back?
    Also, any long term reactions between brass and steel? I could paint the steel first.

    I haven't really worked with brass much yet.
    Thank you.

  • #2
    what kind of brass? there is an infinite number of combinations of copper and zink.
    Last edited by dian; 02-19-2015, 12:15 PM.

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    • #3
      Well steel often runs in brass bearings, so why not,
      Mark

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      • #4
        In time wouldn't the split tend to open up? Or snag? Are you going to braze the seam closed? You'd need to do some calculating, coefficient of expansion, etc., but you could fit a piece from a brass tube, if you got the dimensions correct. You'd need to heat it just enough to get it over the steel and shrink the band on. Still probably have to finish turn the brass afterward.

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        • #5
          Originally posted by dian View Post
          what kind of brass? there is an infinite number of combination of copper and zink.
          Mystery metal acquired long ago.

          Originally posted by Rosco-P View Post
          In time wouldn't the split tend to open up? Or snag? Are you going to braze the seam closed? You'd need to do some calculating, coefficient of expansion, etc., but you could fit a piece from a brass tube, if you got the dimensions correct. You'd need to heat it just enough to get it over the steel and shrink the band on. Still probably have to finish turn the brass afterward.
          I had considered closing the ends by drilling through the brass into the steel then tapping in little pins.

          Overall I don't know what type of brass it is. Possible to tell me if, in general, brass alloys have any spring?

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          • #6
            Brass does indeed have some "spring". I once used a brass rod to make a depth gauge for a raft mounted quarry pump. I made up a frame with a 18" length of 1/4 x 1/2 brass, one end ridgidly mounted to the frame and the raft, and a length of chain hanging from the other end of the brass bar. with the raft in a sufficient depth of water that the chain didn't touch bottom, the weight of the chain deflected the rod, moving it away from a switch. as the pump emptied the quarry, the end of the chain eventually touched bobbom and the bottom carried the weight of the chain rather than the bar. eventually the bar raised to trip the switch. I was careful that the weight of the chain was not enough to bend the bar past its yield point.

            You might consider shrinking the brass onto the steel if it won't see temperature extremes. Brass has a little less than half of the "springyness" of steel, but almost twice the coefficient of thermal expansion.
            Weston Bye - Author, The Mechatronist column, Digital Machinist magazine
            ~Practitioner of the Electromechanical Arts~

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            • #7
              Funny the previous poster didn't mention the use of brass as springs in clocks
              I have a small lathe (george adams) whose brass cross slide dial is slit and grips the shaft well enough after 50 years.

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              • #8
                Baz,
                you give more credit than I deserve. Brass clocksprings never occurred to me. None of my clock designs used springs.
                Weston Bye - Author, The Mechatronist column, Digital Machinist magazine
                ~Practitioner of the Electromechanical Arts~

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                • #9
                  All metals that you are likely to come across have "spring" as you call it. It's call modulus of elasticity. The thinner the ring the greater the "spring" you can achieve without inducing permanent deformation. Also a suitably designed installation tool will allow you to control the amount of spring without over stressing.

                  Phil

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                  • #10
                    On the heat/cool shrink fit, brass has a thermal coefficient of expansion of 19 x 10^-6 per degree C. Steel is about 12 x 10^-6 per degree C.

                    If the steel is cooled to 0 degree C that is about 20 degrees below room temperature. The shrinkage over 1.5" would be about 0.0003". Not very much.

                    If the brass is heated to 260 deg C (500 deg F) the expansion over 1.5" would be 0.0068".

                    You may be able to make that work with a 0.0025" deep slot. But you gotta work fast. Make the brass ring extra thick so it will retain the heat better. Machine the excess off after it cools into place.



                    Another thought may be to force the brass ring on at room temperature. Make the groove 0.005" to 0.010" deep and the brass ring to match. Machine a slight taper on the end of the steel to allow the brass ring to start. Make a steel tube to drive the brass ring over the steel to the groove until it snaps in. I haven't tried this but I think you would need to make the brass ring with extra height so there is enough to actually push against and so it will be strong enough not to break.


                    But I would make the groove deeper than either of the above would allow, at least 0.025" but more would be OK. Make your ring to the final size and split it. You can get soft solder in a paste form: it is used for assembling surface mount parts to printed circuit boards. It is a mixture of powdered solder and flux. Clean the steel and the brass. Put the solder paste in the groove and the brass ring over it. Use the solder paste sparingly or it will coat the exposed brass. This would be hard to clean off. Make an aluminum ring to hold the brass ring in place. Place all of the above in the kitchen oven set to 500 deg F or higher and give it enough time for the solder to melt. Cool it and polish the brass.

                    There are different alloys of the soft solder paste available. I would select one with some silver content as it would be stronger. I think almost any brass alloy would bend enough to allow this procedure.
                    Paul A.

                    Make it fit.
                    You can't win and there is a penalty for trying!

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                    • #11
                      You could modify the operation and get the outcome needed.. Cut steel bar, turn a step to fit the brass then reattach the two pieces of steel, like threading an internal and external section. JR
                      My old yahoo group. Bridgeport Mill Group

                      https://groups.yahoo.com/neo/groups/...port_mill/info

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                      • #12
                        One option would be to experiment with mandrels undersized from your workpiece. Once you've got one which will spring back open to the right diameter or a smidge less, you can measure out measure out enough for final circumference, wrap the mandrel, then pop it in place on the work.

                        Calculate your circumference along the middle of the brass strip. Chamfer the ends a little so they'll meet squarely.

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                        • #13
                          Or to introduce a completely different process. Turn a groove, braze it full and then turn down the rough stuff.
                          .
                          "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

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                          • #14
                            Originally posted by boslab View Post
                            Well steel often runs in brass bearings, so why not,
                            Mark
                            The bearings you may have in mind are usually bronze. Brass does not make a good serviceable bearing.

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                            • #15
                              Originally posted by TGTool View Post
                              Or to introduce a completely different process. Turn a groove, braze it full and then turn down the rough stuff.
                              I like that approach also. JR
                              My old yahoo group. Bridgeport Mill Group

                              https://groups.yahoo.com/neo/groups/...port_mill/info

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