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I Can't Believe Cored Bronze Round Moved

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  • rkepler
    replied
    On something like this I tend to make a fixture to hold the section and turn it individually. If you place 2 of them opposed to one another you can still check the inner and outer 'diameters' and they don't shift. But I mostly do this to reduce material usage.

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  • JoeLee
    replied
    Originally posted by boslab View Post
    Nice job joe, a setup like that broke my last slitting blade, steel tube, went fine till it closed on the blade an bit a chunk out, I'm just lucky I guess, it was thick wall hydraulic tube so I should have guessed.
    Mark
    You were right.... that ring snapped shut on me when I moved the saw out of the cut. I didn't cut all the way through, left about .010 on the inside but the force of the ring wanting to close up was more than that thin amount of material could support. I tried to spread the ring by hand but could barely get it to open up so I cut the segment out with a hack saw and left my mark clear. I measured the ring after I cut the segment out and it closed up .020 on the OD.
    The segment was a little tight fitting in the hub groove so I stoned the top slightly and turned a steel round to the dia. of the inside groove wall taking into consideration the thickness of the sandpaper and lightly sanded the inside radius of the segment. I got a perfect fit. I'll use that one for the master pattern for the other two weights.
    I wonder........... perhaps I should have hole sawed the rings over and under sized out of a piece of 5/16" bronze plate and then turned the ID and OD. Not sure what kind of internal stresses I would run into with plate.

    JL.....................

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  • Rustybolt
    replied
    Obviously stresses built up in the casting process. Maybe anneal it next time?
    I had a lathe job once in bronze with aluminum in it. Take a cut on the OD and the OD grew a couple of thou. Chase that down and the las measurement was undersized.

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  • RichR
    replied
    Originally posted by JoeLee View Post
    I've had stuff like that close up on me just as the blade breaks through. Mostly rolled tube. Most of the time it pops open, but I do remember having some SS sq.tube that closed up and popped the blade of my band saw.. However I don't believe there are any internal stresses waiting to be relieved from anything cut out of a bronze round.
    Bronze has some self lubricity qualities so it shouldn't be an issue.

    JL.............
    Or you could tap a wedge of wood into the hole as a precaution.

    Leave a comment:


  • JoeLee
    replied
    Originally posted by boslab View Post
    Nice job joe, a setup like that broke my last slitting blade, steel tube, went fine till it closed on the blade an bit a chunk out, I'm just lucky I guess, it was thick wall hydraulic tube so I should have guessed.
    Mark
    I've had stuff like that close up on me just as the blade breaks through. Mostly rolled tube. Most of the time it pops open, but I do remember having some SS sq.tube that closed up and popped the blade of my band saw.. However I don't believe there are any internal stresses waiting to be relieved from anything cut out of a bronze round.
    Bronze has some self lubricity qualities so it shouldn't be an issue.

    JL.............

    Leave a comment:


  • boslab
    replied
    Nice job joe, a setup like that broke my last slitting blade, steel tube, went fine till it closed on the blade an bit a chunk out, I'm just lucky I guess, it was thick wall hydraulic tube so I should have guessed.
    Mark

    Leave a comment:


  • mattthemuppet
    replied
    I'd just cut them with a hacksaw and file them to suit, but I'm guessing that isn't the finish you're aiming for

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  • JoeLee
    replied
    I think this is the way I'm going to slice the segments off the ring.
    I scribed the ring using my center gage. I spaced the scribe marks .625 apart on the OD. I'll use the parallel to line the scribe marks up as shown and bring the saw down until it touches the parallel. Once I cut one segment I can use it for a pattern for the others.





    JL...............

    Leave a comment:


  • garyhlucas
    replied
    Three pounds of chips, lots of actaul labor, elaborate setups, more tooling. Why CNC is making more and more sense for the home shop! About 15 minutes to draw this and program in CamBam, then watch it cut. I get it, you aren't in a hurry, but it is nice to finish minor stuff quickly so you do more interesting projects. CNC is getting cheaper all the time at a very fast rate right now due to the influence of 3d printers.

    Leave a comment:


  • JoeLee
    replied
    Yes, that is the way I had originally figured I would have to go about this without getting too elaborate.

    The other thing I was wondering about was how big or long should I make each weight?? I know that in this case it's not size that matters but the weight of each segment, weather they are all perfectly equal shouldn't really matter.
    I do know that even one segment that is about 1/2" long is probably five times heavier than any 7" x 1/2" wheel could be out of balance.
    But this is relatively new territory for me. I'm pretty much going by what I see in other manufactured hubs.

    JL...............

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  • RichR
    replied
    Originally posted by JoeLee View Post
    I thought of this but I don't want to remove the chuck from my RT and go through all the set up. Got to be an easier way.

    I can scribe the lines and was thinking of clamping the ring in the mills vise and slicing through it with an .020 slitting saw.
    However this still presents an issue as far as getting the angles all the same and the length of each segment the same.

    JL..............
    Then carefully chuck up the ring and make scribe marks 120 degrees apart. You can do this on the lathe or rotary table. Now you should be
    able to clamp it in the vise and and line the scribe lines up with the slitting saw.

    Leave a comment:


  • JoeLee
    replied
    I thought of this but I don't want to remove the chuck from my RT and go through all the set up. Got to be an easier way.

    I can scribe the lines and was thinking of clamping the ring in the mills vise and slicing through it with an .020 slitting saw.
    However this still presents an issue as far as getting the angles all the same and the length of each segment the same.

    JL..............

    Leave a comment:


  • RichR
    replied
    Originally posted by JoeLee View Post
    Does anyone have any ideas on how I can fixture each weight segment after I rough cut each one out of the ring????

    After I cut each segment out I would like to make sure each one is the same size and the angle cuts are the same.
    I need some thoughts on how to set up to do this.

    JL.................
    Center and clamp it to a rotary table. Run a thin endmill through it to make a cut. Crank the table 120 degrees, add clamps if necessary, and
    make the next cut.

    Leave a comment:


  • JoeLee
    replied
    Does anyone have any ideas on how I can fixture each weight segment after I rough cut each one out of the ring????

    After I cut each segment out I would like to make sure each one is the same size and the angle cuts are the same.
    I need some thoughts on how to set up to do this.

    JL.................

    Leave a comment:


  • JoeLee
    replied
    It sounds like it's not worth the time and effort. I had thoughts of perhaps melting it down and casting a small bar that might come in handy for a future project. There may also be some steel swarf in the mix. I may be able to pick it out with a magnet but if I don't get it all I'm not sure how it will come into play in the mix. Will it separate from the molten bronze???
    The other thought that occurred to me after watching the video of the guy casting the apple is I may end up with a lot of voids in the bar which would make it unusable in most cases. Not sure if it changes the strength or integrity of the material either, and I would probably use more gas to melt the stuff that it's worth.

    JL.................

    Leave a comment:

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