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    Default Free State

    What does it mean to machine material in a free state? When is it applicable? Materials? Is it a actual technique or something passed around as science?

    Thanks for excusing my ignorance.

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    In my experience that means unstressed or unconstrained. That is, suppose you have4 a weldment set up for machining that might have irregular contacts with the table so that clamping warps it slightly. Machining is done and dimensions checked before unclamping. Everything looks good. Once removed from the clamping stresses and in its "free state" some dimensions may be off.

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    Probably the closest to "free state" would be to mount the work with shellac "wax" or some kind of putty that hardens. This is often done for extremely irregular shapes that may vary slightly from piece to piece and would be extremely difficult to clamp.

    The piece gets "stuck" onto a mounting plate or mandrel for machining. Of course it then has to be "unstuck" without damage after machining.

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    Quote Originally Posted by Scottl View Post
    Probably the closest to "free state" would be to mount the work with shellac "wax" or some kind of putty that hardens. This is often done for extremely irregular shapes that may vary slightly from piece to piece and would be extremely difficult to clamp.

    The piece gets "stuck" onto a mounting plate or mandrel for machining. Of course it then has to be "unstuck" without damage after machining.
    I hear it referred to as mounting wax.

    First result on the search engine. PELCO(R) Mounting Waxes

    Sent from my SAMSUNG-SM-G891A using Tapatalk

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    Used a lot of zip-lock-type plastic bags partially filled with a "liquid shim" compound (plaster of Paris, anchoring cement, precision grout, or Hydrocal-type tooling plaster, or rarely, epoxy) mixed to a pea-soup-to-pancake- batter consistency to fill gaps between a casting or weldment and a temporary mounting surface.

    The polyethylene of the bag is compressible, but it was, to the best of my recollection, never a problem.

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    Quote Originally Posted by Selvidge209 View Post
    What does it mean to machine material in a free state? When is it applicable? Materials? Is it a actual technique or something passed around as science?

    Thanks for excusing my ignorance.
    Fair question , actually.

    "Non-distorting" clamping or fixturing, modest exposure I've had. Or "best efforts" that let you still DO something useful.

    Can't very well levitate the average item with NO constraints as if it were a hunk of rock in outer space, and the most stressful machine tool was nowt but a camera LOOKING at it, can one?

    FWIW-not-much, even a magnetic field or a beam of light impinges distorting force on an object. So does gravity, no matter how weak or distant.

    But if we are into Heisenberg's uncertainty principle?

    Best let Schrödinger's cat do the QC?

    Should get exactly a 50% pass/fail rate? Wouldn't be the first time 50% yield had to make-do?



    So "back to square ONE". Same as any OTHER tasking:

    Whom is going to DO the QA?

    What will they seek for acceptance?

    HOW will they measure for it?

    What are Plan A and Plan B to prevail?

    Basically belly-driven. Folk like to EAT reg'lar-like. No plan? No bid.

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    In grinding free state is holding the part with little or no clamping pressure so the part has no distortion.
    one example is the DedTrue surface grinder attachment. UNISON DedTru(R) Centerless Grinding Fixture | FlexMech Engineering It is not uncommon to grind the likes OD a small diameter reamer in its unfluted state to 2 microns with such an attachment / a feat almost unattainable with other methods.

    Another example might be gluing or just setting a part on the chuck or using little or no magnetism, but perhaps blocked in in the go directions.

    I used to grid round parts like dead perfect machine centers with them set on 4 bearings so to be like setting on/on a steady rest with only wheel pressure holding the part in place. yes with the but center or a point stop holding true to endways movement.

    Yes, the part must be stable in itself so its integrity does not distort in its structural being because a thin part or long part may distort from grinding wheel or cutting tool pressure.

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    Free state is a condition that a part sits in a fixture the same exact way that it would if you set the part on the table and haven't put any clamps or put it in a fixture with tension on it. Material doesn't matter. Ideally it is applicable with any part, but when I used to free state parts, they were large and had tight tolerances. I would either put the part in the vice or on an angle plate and run and indicator close to the clamps. The clamps would be just tight enough to put tension on the part, and when I got close to a clamp, I would loosen the clamp and watch the indicator. If it moved .005, I would place a .005 shim between the part and the plate. Double check that there was no indicator movement and go to the next clamp. This gets repeated with all clamps until there is no movement in the needle. It is a practiced skill and should be done each time the part is set up for a new process. It can be a pain in the nuts, or be a quick job. There is no predicting. If anyone would like to add or correct, feel free. I am a bit rusty at it.

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    Quote Originally Posted by chuckg7442 View Post
    Free state is a condition that a part sits in a fixture the same exact way that it would if you set the part on the table and haven't put any clamps or put it in a fixture with tension on it. Material doesn't matter. Ideally it is applicable with any part, but when I used to free state parts, they were large and had tight tolerances. I would either put the part in the vice or on an angle plate and run and indicator close to the clamps. The clamps would be just tight enough to put tension on the part, and when I got close to a clamp, I would loosen the clamp and watch the indicator. If it moved .005, I would place a .005 shim between the part and the plate. Double check that there was no indicator movement and go to the next clamp. This gets repeated with all clamps until there is no movement in the needle. It is a practiced skill and should be done each time the part is set up for a new process. It can be a pain in the nuts, or be a quick job. There is no predicting. If anyone would like to add or correct, feel free. I am a bit rusty at it.
    Concur.

    I'm prolly even rustier.

    I exercised the 'free state", early-on of not wanting to be bothered, went and did something else.

    Life was still full of pressures and distortions.

    But at least they weren't so damned PICKY nor unpredictable.

    And you even got to push back if you were on your game!


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    I’ve come across cerromatrix used to hold for machining, low melt conforms without applying mechanical stress, was handy on the surface grinder too,
    Mark

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    Quote Originally Posted by boslab View Post
    I’ve come across cerromatrix used to hold for machining, low melt conforms without applying mechanical stress, was handy on the surface grinder too,
    Mark
    You left out highly recoverable and very nearly 100% re-usable, too.

    Much nicer to work with than "one time" plaster and faster than setting up poxy-putties.

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    Quote Originally Posted by John Garner View Post
    Used a lot of zip-lock-type plastic bags partially filled with a "liquid shim" compound (plaster of Paris, anchoring cement, precision grout, or Hydrocal-type tooling plaster, or rarely, epoxy)m.
    I just did this on the weekend to hold a small headstock casting in a mill vise so I could mill the bottom. I used bondo in a baggy, it worked well. The part gets scraped afterwards so wasn't super worried about the nth level of precision, but after setting and clamping up in the vise and carefully indicating the upside down bottom, it seemed work perfectly.

    Wax chuck work is common, or probably more correct to say was, in watchmaking work. Small stuff, where the pivot (think journal) on a shaft might be .004" tho. I've done it and its considered the most accurate way to get things spinning with perfect concentricity to an existing surface. The wax is really shellac. you melt a small bit on a 'wax chuck'. and put the part in the wax. To get the part aligned, with the lathe turning, you hold a flame under shellac and at the right temperatures it holds but is pliable. Then you bring something (using a rest) into contact with the work and every so carefully push the work into alignment. It takes a bit a practice to get the temps right, but imo is a neat process as perfect alignment is achieved with the simplest of tools.

    To remove the shellac afterwards? drop it in a test tube of alcohol and boil it over a flame....they come out perfectly clean
    Last edited by Mcgyver; 09-07-2021 at 06:35 PM.

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    That means you machine it in New Hampshire.

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    Quote Originally Posted by jscpm View Post
    That means you machine it in New Hampshire.
    But you would have a 50:50 chance of dying! They are unbaised bipolar!

    Or even BOTH?

    "Live free OR die" not "Live free XOR die" (XOR is 'exclusive OR')

    Preston County West Virginia, AKA "the Free State of Preston" is where you wanna bee!


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    Quote Originally Posted by thermite View Post
    But you would have a 50:50 chance of dying! They are unbaised bipolar!

    Or even BOTH?

    "Live free OR die" not "Live free XOR die" (XOR is 'exclusive OR')

    Preston County West Virginia, AKA "the Free State of Preston" is where you wanna bee!

    Thought that Houston was supposed to be the free state.

    Sent from my SAMSUNG-SM-G891A using Tapatalk

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    Quote Originally Posted by Selvidge209 View Post
    What does it mean to machine material in a free state? When is it applicable? Materials? Is it a actual technique or something passed around as science?

    Thanks for excusing my ignorance.
    To machine a material in deep state. The shop has to be underground with no windows, no natural light.
    The building must be surrounded by a fence with concertina wire on top. One more thing. The boss did
    not interview for his job position. He was appointed by a bunch of rich globalists.

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    Quote Originally Posted by rons View Post
    To machine a material in deep state. The shop has to be underground with no windows, no natural light.
    The building must be surrounded by a fence with concertina wire on top. One more thing. The boss did
    not interview for his job position. He was appointed by a bunch of rich globalists.
    FREE state. Not DEEP state. Wayyyy different parts they make.

    Sent from my SAMSUNG-SM-G891A using Tapatalk

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    Little surprised that Don didn't kill the thread due to the meaningless tittle. Glad he didn't, there's some good info here.

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    I've never come across a drawing stating "machine in a free state".
    But a few that state "Inspect in a free state"....which is the important thing....in reality?

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    Quote Originally Posted by barbter View Post
    I've never come across a drawing stating "machine in a free state".
    But a few that state "Inspect in a free state"....which is the important thing....in reality?
    In reality it is implied by the print, for example getting a 6 foot aluminum plate to stay within +/- .01 of an inch with several 2 foot holes milled out of it. What fun I used to have at work.


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