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Thread: Pillar to action mating surfaces

  1. #1
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    Pillar to action mating surfaces

    I assumed that the pillars and action should have as much contact surface as possible, but read others keep a set amount of clearance for the bedding. Why wouldn’t we want the stock, action, screws and pillars to be as close to one unit as possible?

  2. #2
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    I'm very curious as well. I've done it both ways and am not good enough to say if one way worked better than the other.

  3. #3
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    In my case I'm trying to get the action to sit as tightly as possible into the bedding not onto the pillar. In theory I will agree that sitting on both is the ideal situation, but sitting into the bedding is what you're after. I generally use a flat top pillar and bed over that to get the action down tight. I've also seen pillars come loose from cranking down on the action screws when the pillars weren't against the action or against the bedding, so as always you can screw something up anyway you approach it.

  4. #4
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    For Remington size actions I made a fly cutter decades ago to cut the radius slightly under the action diameter. I mount the pillars tight to the action then bed as a single unit. No bedding needed on top of the pillars. I only bed a 5/8" strip down the middle of the action and the rear of the recoil lug. Essentially doing it this way the action is sitting in V-blocks.

  5. #5
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    So, Dave, you're not 'encasing' the entire action in bedding? Just the bottom? Do you have a picture of the bedding? I'd love to see it. I bedded one like that in the past and was told "you can't do it that way". LOL

  6. #6
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    Quote Originally Posted by Dave Tooley View Post
    For Remington size actions I made a fly cutter decades ago to cut the radius slightly under the action diameter. I mount the pillars tight to the action then bed as a single unit. No bedding needed on top of the pillars. I only bed a 5/8" strip down the middle of the action and the rear of the recoil lug. Essentially doing it this way the action is sitting in V-blocks.
    Cool. Never thought of the strip of bedding. I like the v block idea. I bought some before I had a mill but didn’t care for their design. I’ll try this way. Thanks

  7. #7
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    Quote Originally Posted by clowdis View Post
    In my case I'm trying to get the action to sit as tightly as possible into the bedding not onto the pillar. In theory I will agree that sitting on both is the ideal situation, but sitting into the bedding is what you're after. I generally use a flat top pillar and bed over that to get the action down tight. I've also seen pillars come loose from cranking down on the action screws when the pillars weren't against the action or against the bedding, so as always you can screw something up anyway you approach it.
    Thanks. I was trying to mimic a glue in one piece unit in my mind. I’m good at screwing up

  8. #8
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    Quote Originally Posted by parshal View Post
    So, Dave, you're not 'encasing' the entire action in bedding? Just the bottom? Do you have a picture of the bedding? I'd love to see it. I bedded one like that in the past and was told "you can't do it that way". LOL
    Id like to see a pic too. Always makes more sense.

  9. #9
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    Jan 2020
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    I'm a newbie to most of this, so I'm still learning. If the action does not make contact with the pillars, and sits on the bedding only, then why have pillars to begin with?

  10. #10
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    Bedding

    When I started bedding in the early 70's the entire job was done with Devcon aluminum, I still to this day do my personal bedding jobs this way. It was a 3 time (most of the time and some times 4) job, pillars then complete action area and final was a skim coat to finish. (The exception has been on BR stocks of Red Wood that I was concerned with weight)
    When drilling a 5/8 hole in the back thru the stock and a ¾ hole thru the stock on the front action screw then pour with Devcon aluminum and getting it to stay in place is to say the least fun! Most used putty for the pillars and first coat on action area but for me didn't like the voids so I did and still do it in liquid.
    Today I use short pillars turned from aluminum bar stock then bed over them, much easier to keep everything in place and not have voids. Many different ways to do the job and have it work......... I have had the turned pillars come loose, my fault or so I think due to prep on them and this is one reason I still do not like them. Can't say they are a bad way to go or the way to go but for me the pouring is the most positive way even though time consuming.

    Just my 2 cents........

    Rick

  11. #11
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    I knurl the outside of my pillars before gluing them in. Bead blast and clean thoroughly with acetone also. Have not had one come loose.

  12. #12
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    I don't have any pictures but I'll tell how I do it. I was in Northern Tool a long time ago and on the dollar table they had some 1" electrical tape. I bought a couple of rolls. Turned out it was very thin. I got the idea of taping up most of the action. Stocks continue to move and that includes fiberglass also as they continue to cure some. I install the pillars on the action. They leave a nice mark to act as a guide for the tape. I lay the tape on, front to rear and trim it tight against the recoil lug. Then tape the lug over, sides, bottom and front. Another piece in front of the recoil lug on the barrel and a piece of 2" masking tape covering the stock in front of the action. Add paste wax, install pillars, coat pillars with bedding compound, coat stock, then assemble. The tape comes up past the side of the stock and makes clean up a breeze. I put grooves in my pillars when I turn down the OD to fit 5/8" holes. I recommend using tape regardless of the contact width even if it's a 1/4" on the sides below the stock line. It makes clean up so easy.

  13. #13
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    I run a light cut 32 TPI on the pillars....005-.010 deep. It raises the surface just enough to provide a snug fit and nice cavities for the epoxy. If they are a little tight they will sometimes turn into the stock cutting the threads as they go in. Never had one come loose.

    I let the pillars sit high in the stock and machine to the desired height after the epoxy has cured.
    Last edited by Ricco1949; 01-15-2020 at 03:17 PM.

  14. #14
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    Quote Originally Posted by Dave Tooley View Post
    For Remington size actions I made a fly cutter decades ago to cut the radius slightly under the action diameter. I mount the pillars tight to the action then bed as a single unit. No bedding needed on top of the pillars. I only bed a 5/8" strip down the middle of the action and the rear of the recoil lug. Essentially doing it this way the action is sitting in V-blocks.

    .....

    I don't have any pictures but I'll tell how I do it. I was in Northern Tool a long time ago and on the dollar table they had some 1" electrical tape. I bought a couple of rolls. Turned out it was very thin. I got the idea of taping up most of the action. Stocks continue to move and that includes fiberglass also as they continue to cure some. I install the pillars on the action. They leave a nice mark to act as a guide for the tape. I lay the tape on, front to rear and trim it tight against the recoil lug. Then tape the lug over, sides, bottom and front. Another piece in front of the recoil lug on the barrel and a piece of 2" masking tape covering the stock in front of the action. Add paste wax, install pillars, coat pillars with bedding compound, coat stock, then assemble. The tape comes up past the side of the stock and makes clean up a breeze. I put grooves in my pillars when I turn down the OD to fit 5/8" holes. I recommend using tape regardless of the contact width even if it's a 1/4" on the sides below the stock line. It makes clean up so easy.
    I'm having a tough time picturing this so please bear with my questions.

    The radius you're cutting with your fly cutter, is that a radius on the top of the pillars?

    The second post sounds like you're covering the entire bottom of the action with the tape so that pillars are "proud" of the stock by the thickness of the tape after bedding. Or, are you taping the sides of the action down to the bottom but leaving a 5/8" strip of "tapeless" action from pillar to pillar thereby having that bedding support the action along with the pillars?

  15. #15
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    Quote Originally Posted by penn63 View Post
    I'm a newbie to most of this, so I'm still learning. If the action does not make contact with the pillars, and sits on the bedding only, then why have pillars to begin with?
    Some things;

    First, true tuneable accuracy is about vibration control, about making the rifle system into a repeatable, predictable constant. Something tractable, like a car, turn the key and let the car do it's job. Bedding, any bedding is about #1 equalizing or balancing touch points (hence "bedding") and #2 making this bed into a stable tractable surface that stays CONSISTENT, reacts CONSISTENTLY day-to-day. One problem with AL pillars touching the action is simply that one absolutely cannot get two metal surfaces to meet with consistent pressure. Get 'em close, leave a gap and fill the gap with bedding material. Gap too thin, bedding material will break, flake out, NOT do it's job of mating surfaces to equalize pressure. Too thick??? Well, here's a whole nuther kettle a' wurms..... but in answer (from ME, my perspective) to your question of "why have pillars to begin with" you do not NEED pillars, as in disparate AL pillars, but you need SOMETHING.

    Lissen closely to Rick. The "pillars" can be accomplished many different ways.

    And second, what does bedding DO??? It allows you to TIGHTEN or pre-stress the system consistently by giving you a stable bed, and in perfect world this stable bed reacts to firing forces consistently and not only resists LOOSENING but gets up and lays down the same all the time. . . . . . . and there's a horrendous amount of getting up and laying down! This is not a passive situation, instead it's a VIOLENT getting up and laying down. Like mainly the barreled action assembly is doing it's level best to RIP itself out of the stock.....


    V I O L E N T

    Set down and visualize the firing forces....... #1, pushback. BAMM! you hit the end of the end of the barrel with a baseball bat which sends ripples thru the system. But never does it push straight back. Since the BAMM! occurs back at the chamber, and since your barrel is drooped or bent by gravity one force is that the barrel flips, or whips like a firehose straightening out. In other words, the barrel itself has it's own rotational component.... a VIOLENT component, ask any fireman. My son-in-law lost a tooth that way. Add to this the rotation the rotation around center of gravity and you've a a system that most often rotates UPWARDS the muzzle, around the center of gravity. And depending on dimensions and weights of components this CG is a moving target.

    Put on a heavy enough scope and it might just flatten out....

    HOW the system rotates is huge, but that it DOES rotate is unquestionable truth. And most often the rotation is up and back, like not only did you BAT the barrel but you batted it UPWARDS for a home run. In the end the result is that in most systems there's a tremendous UPWARD component added to the pushback.... not to mention the violent side-to-side whipping component. Some manufacturers (Lyman to name one) and wannabe experts have characterized this as a "figure-eight" at the muzzle but this is overly simplified IMO.

    Barrels are bent..... barrels are not straight..... barrels are helixed..... barrels are made crooked......basically what I'm saying is barrels themselves all whip differently. And THE SAME BARREL re-set and indexed through the hours of the clock will cause the system to react differently at each setting.

    And thirdly, when it comes to real accuracy, it must be noted that the rifle is a SYSTEM. Barrel, action, scope and stock ALL play into the system. And the entire SYSTEM must act consistently through the entire time the bullet is in the barrel and then must come back to passive rest same-same every time.....

    A hunting rifle with a 20oz Leupold will not flex the same as the same rifle with a 40oz Schmidt and Bender. It'll rotate around a different center due to changed CG

    Nor will two hunting rifles built on different actions flex the same......different setups, different rules, different bedding procedures..... 700 vs 70 vs 77 vs 110 vs T3 vs Panda..... completely different issues involved. DIFFERENT bedding procedures required.


    here are some variables;

    ht of scope from bore centerline
    weight of scope (change scopes, change flex characteristics)
    barrel time/distance as in time bullet is in barrel during the recoil cycle (different powders)
    type and distance and number of screws in action. Actions flex and flop under recoil like a fish in the rocks.
    length/caliber/weight/chambering/configuration of the barrel. ALL change the flex/flop. Adding a barrel device increases stress on bedding.

    etc etc... but all pointing to the same problem. FLEX.

    Bedding is to control FLEX, to make a gun tractable it must be made to flex violently and return to rest thousands of time....



    And then OTHER stuff flexes and fails LOL






    I recently was fighting with a broken gun only to find out that the rifle was fine but the scope base was moving...... my dovetail base interface was buggered up...... the two surfaces were not perfectly angle-matched and due to the way things were slotted the base was warping slightly when tightened allowing it to rotate under load. It didn't show up until I'd mounted a 3.5lb scope to it......

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