Pillar metal. Aluminum or stainless?

Discussion in 'Gun Project Questions & Gunsmithing' started by Macropod, Oct 12, 2018 at 2:17 AM.

  1. Macropod

    Macropod

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    Which would be preferable?

    My thinking unless weight is an issue, is to use stainless, being that it has less thermal expansion changes in temperature.
     
  2. jds holler

    jds holler Gold $$ Contributor

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    I can't fault your logic, and it is obvious that you are a deep thinking individual; or perhaps one who is anal and picayune, about things which we have no control over.:p I sometimes suffer the same malady. :) jd
     
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  3. Macropod

    Macropod

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    Yep. That about sums me up!:)
     
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  4. Grimstod

    Grimstod Machinist, Designer, and Shooter. Gold $$ Contributor

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    Aluminum would be my choice. It is softer and sets the rifle into the bedding better. Same reason i do not worry about the thermal of aluminum is the same reason i have no hesitation to use a scope. They are all made from aluminum by the way.
     
  5. RJ

    RJ Silver $$ Contributor

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    If you're worried about thermal issues, Use G-10
    I use G-10 for pillars in all the rifles that we build.
    It machines very well and is available in just about any diameter you'll need. It's available at MSC. There are some of us that believe rifles shoot better without the metal to metal contact on the pillars. This will probably start a debate on that subject.

    Richard Hilts
    Hilts Accuracy Custom Rifles
     
    Last edited: Oct 12, 2018 at 6:06 AM
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  6. Bully

    Bully Gold $$ Contributor

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    This sounds like something I'd like to try. Any idea where to buy just a few 2.25"x 9/16" pieces? Maybe 4? I'm a hobbyist for the moment, and don't need a large amount.
     
  7. eddief

    eddief Gold $$ Contributor

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    I have used 303 stainless, aluminum, G10 and brass for pillars over the last 20 yerars. Never seen a difference on paper when done right. For what it's worth when doing my own, I use what is most convenient. Customers get what the want.
     
  8. Dusty Stevens

    Dusty Stevens COVFEFE Gold $$ Contributor

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    Im with richard on the pillar touching the action part- i wont do it not even a nub. When the bedding shrinks later youll only be touching the pillar
     
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  9. ricco1949

    ricco1949 Gold $$ Contributor

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    Devcon steel putty has a shrinkage rate of .0006 cm/cm, that's about .0038 in/in. Assume .050 inch protrusion of pillars above the stock inlet and a skim coat of Devcon steel liquid over the 1st Devcon bedding coat. Granted you still have shrinkage around the pillars on the skim coat but if I've done the math correctly its .00000075 or 3/4 millionths inch.

    .0006 Devcon steel putty shrinkage rate cm/cm
    2.540 cm/in
    .00152400 Devcon shrinkage rate cm/in
    .00387096 Devcon shrinkage rate in/in
    .050 Typical inches of bedding
    .00019355 Typical shrinkage 1st coat inches
    .00000075 Typical shrinkage skim coat inches

    Seems like a skim coat takes care of the shrinkage issue..... but a glue in would still be better.
     
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  10. GSPV

    GSPV A failure to plan is a plan for failure. Gold $$ Contributor

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    Anyone cast epoxy pillars in place? I’m fascinated by the idea.
     
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  11. ricco1949

    ricco1949 Gold $$ Contributor

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    I started out casting the pillars but changed to aluminum. I put fine 32 threads per inch on the pillar, just enough for a friction fit, and use that to adjust the pillar height and provide a good grip for the epoxy. If matched perfectly the threads will turn in the pillar hole.
     
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  12. NorCalMikie

    NorCalMikie Gold $$ Contributor

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    Stainless Steel barrel stubs. (if you've got the machine to turn it to size)
    Aluminum will also do the job and I doubt very much you'll be crushing it. ;)
     
  13. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market

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    I think the subject of thermal expansion and pillars is a solution looking for a problem, but if it's a concern, I think pouring the pillars is the best option. That said, its shrinkage(devcon 10110) is a non issue IMO, and as pointed out by ricco above. Whatever you use as a release agent likely takes up considerably more space than the shrinkage. Just my 2 cents worth.
    We simply get a little carried away about some things in the precision rifle business. We should worry more about....virtually anything. Keep in mind that a 1 inch peg does not fit into a 1 inch hole. They are the SAME. For one to fit into the other, they can not be the SAME and must have clearance....or a hammer. ;)
     
  14. Alex Wheeler

    Alex Wheeler Gold $$ Contributor

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    I have measured more than that. And if you look at the way stocks are inletted, there is generally a lot more than .050" especially in the tang area. But I agree a thin EVEN skim coat is the best way to minimize the shrinkage. There are also techniques to make the bedding hug/squeeze the action. I have had good luck with that process with Pandas. I do think bedding is a flawed process in general and fussing over technicalities of a flawed process doesnt gain you much.
     

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