Pillars

[double g]

Should pillars go all the way to the bedding

 

[jonbearman]

Yes ,they should contact the reciever.

 

[Bob3700]

Pillars should extend thru the bedding to the action and then to the bottom of the stock.

If wood is left anywhere, you can compress the wood and the effect of the pillars is negated.

Bob

 

[Steve Blair]

This article by Richard Franklin is pretty informative.

http://www.accurateshooter.com/technical-articles/stress-free-pillar-bedding/

 

[BoydAllen]

A number of years ago, I had a conversation with George Kelbly. One of the things that I asked him about was pillar bedding. He told me that back wieh it was first developed, it did not take them long to figure out that for Benchrest. that metal to metal wasn't the way to go, that it was preferable, from an accuracy point of view, to have at least a skim coat of bedding between the receiver and the tops of the pillars. It has been a while, but that last time that I did one, I made pillars that were a larger diameter under the action, and small enough to hide under the floor plate on the bottom. They were flat topped, and were held well down below the action. I bedded over them, with Devcon aluminum,at the same time that I did the rest of the action. There was probably 1/4" of bedding material between the tops of the pillars and the action. It shot just fine. You might want to remember that a high quality (Benchrest accuracy) pillar bedding job can be done using cast in place pillars.

 

[sailhertoo]

Interesting.

I just thought I screwed up my new piller job when I "accendently" left them too short and have about 1/4 " bedding on top of them.

I don't feel so bad now. Thanks

 

[Steve Blair]

Boyd,

So do the pillars then just become screw guides and impingement surfaces for the screw heads?

 

[BoydAllen]

Not at all, they allow the action screws to be tightened to a point that the unit loading of the bedding in increased to a point where the action stock interface becomes more stable. Metal against metal lacks the interlocking of surface texture that is provided by a metal filled epoxy. The latter has more "traction" and is sufficiently incompressible to prevent the action being stressed by distortion of the stock at higher action screw torque values. This is not to say that metal to metal is bad, just not quite as good. Years ago a fellow that wrote for Precision Shooting Magazine, Merril Martin, was working with a Savage action barreled in .308 and shooting 190 grain bullets. The stock was bedded with contoured aluminum pillars, that were metal to metal with the action. After shooting a number of rounds, inspection of the tops of the pillars showed fret marks, that indicated that there had been some movement of the action on the pillars due to the torque generated when firing the heavy bullets. Being an inventive, and out of the box thinker, Merril dusted the tops of the pillars with a thin layer of carbide abrasive particles to increase the traction between the parts, and reassembled the rifle, torquing the action screws as before. Targets that were fired after this change showed an improvement in accuracy over those that were produced with the same loads before the modification. Pictures of both sets of targets were published with the article. Good pillars may be fabricated from a variety of materials, and may also be cast in place, of suitable materials, Devcon aluminum putty, with a skim layer of a runnier version (to compensate for shrinkage due to the depth of the pillars) of the same material, has been used to produce very good pillar bedding. As long as pillars do not compress, fit well, and are secure in the stock, they will work. Their is nothing magic about their being made of metal.

 

[Steve Blair]

Without trying to be argumentative; what you just wrote constitutes a yes to my question. I am not disagreeing with the approach you describe, just noting that the pillars are reduced to serving as a place against which the screw head can exert tension. I have two stocks bedded this way, several with conventional pillars and a couple with integral aluminum bedding blocks. As a High Power shooter, it is likely that I cannot discern the difference that would be apparent when shooting BR aggregates. The only time that I shoot from a bench is when doing load development or chronographing. The rest of the time, I'm on my belly.

 

[BoydAllen]

As a matter of fact, if I remember correctly, Mid Tompkins says that he has never been able to get pillar bedding to work as well as more conventional "glass" bedding. No, what I wrote does not remotely mean the same thing as what you wrote. We shoot different sports. I couldn't shoot prone if my life depended on it. On the other hand, a rifle that could win matches at the national level, would pretty much be in last place in a benchrest match. As long as you can do what your need to do, you don't need to understand the finer points of benchrest bedding. God bless.

 

[Steve Blair]

Boyd,

If you cannot or do not want to answer the question; fine. I do not care what sport you shoot, what Mid Tompkins says or whether you can shoot prone. None of that is relevant. I can also do without your sanctimony and snide condescension.

It is a simple, mechanical question. If there is ¼" bedding between the pillar and the action, what purpose does the pillar serve? Why not eliminate the pillar or shorten it further?

 

[BoydAllen]

Let me try again. Pillars do not have to me made of one material throughout their entire length. As long as combination or stack is not compressed when the action screws are tightened, it is a true pillar, that functions as it should. I thought that I made this clear. Evidently I failed. If the bedding material is sufficiently hard, it will not compress, and if a column (pillar) of incompressible material surrounds each action screw, extending from escutcheon, trigger guard, or floor plate to the action surface, then the stock can be said to have fully functional pillar bedding. In the case that you described, the layer above the top of the pillar functions as a part of the pillar. A pillar does not have to be a separate piece of metal that is installed in the stock. In fact, it can be made entirely of the material that the action is bedded with, so if by pillar you mean a piece of metal, yes it can be made a lot shorter. There is no need for a piece of metal, as long as there is some sort of incompressible material in the same location. I hope that this is sufficiently clear. Sometimes forum communication suffers because one cannot see the facial expression of the person that has written a post. While it is true that I could have been a little less condescending, I suppose that I was a little frustrated because, to me, it seemed as if you had completely ignored what I had taken the time to write. Generally, when I explain things, people seem to understand. Evidently, in this case I failed. If my tone offended anyone, I apologize.

 

[Steve Blair]

Boyd,

Thank you for your answer. While I would not want to tighten the screw head directly against bedding compound, I understand your point.

As an aside; do you glue your actions in the stock or make them removable?

 

[sailhertoo]

Not at all, they allow the action screws to be tightened to a point that the unit loading of the bedding in increased to a point where the action stock interface becomes more stable. Metal against metal lacks the interlocking of surface texture that is provided by a metal filled epoxy. The latter has more "traction" and is sufficiently incompressible to prevent the action being stressed by distortion of the stock at higher action screw torque values. This is not to say that metal to metal is bad, just not quite as good. Years ago a fellow that wrote for Precision Shooting Magazine, Merril Martin, was working with a Savage action barreled in .308 and shooting 190 grain bullets. The stock was bedded with contoured aluminum pillars, that were metal to metal with the action. After shooting a number of rounds, inspection of the tops of the pillars showed fret marks, that indicated that there had been some movement of the action on the pillars due to the torque generated when firing the heavy bullets. Being an inventive, and out of the box thinker, Merril dusted the tops of the pillars with a thin layer of carbide abrasive particles to increase the traction between the parts, and reassembled the rifle, torquing the action screws as before. Targets that were fired after this change showed an improvement in accuracy over those that were produced with the same loads before the modification. Pictures of both sets of targets were published with the article. Good pillars may be fabricated from a variety of materials, and may also be cast in place, of suitable materials, Devcon aluminum putty, with a skim layer of a runnier version (to compensate for shrinkage due to the depth of the pillars) of the same material, has been used to produce very good pillar bedding. As long as pillars do not compress, fit well, and are secure in the stock, they will work. Their is nothing magic about their being made of metal.

Wow, some big words in there. I really do understand what you are saying though and I even feel better now.

The pillers are not just screw guides but are imbedded in the epoxy bedding so any tighting of the screw is tighting the whole bedding "block".

If the pillers go all the way to the top, it is a kin to this I think.

Imagin squesing a rubber washer between two metel washers with a nut on a bolt. Put a bushing inside the rubber washer a litte shorter than the rubber is thick. Now tighten the nut down on the bolt until the washer rubber washer is compressed and you bottom on the bushing. You have tightened as much as you can and the rubber washer is compressed.
But, what if the rubber washer shrinks some, you cannot tighten down on it any more because of the bushing. If the bushing was'nt there( ie pillers not going to top) , you would always be tourqing directly to the rubber washer.(bedding)

That small amout of contact to the top of the piller creates a "moment", that keeps the action from being completely married to the bedding and the stock.

I'm I thinking in the right direction?

 

[Frankr]

i have a piller bedding job comming up and i have asked some questions and seemd no one wanted to talk about it and the thread went dead.
This is good stuff, im getting some info on bedding now.
i understand what boyd is saying, i have had several rifles out of the stock that have been piller bedded and there is allways scratching on the bottom of the action that says, its moved or been rubbing, i think this is why richard franklin perfers to not use the contoured pillers and use a flat top piller,because it allows you to have a solid contac point between the screw/piller and action but give you more grip. but i have contoured pillers that im useing and think they will work fine and if i have a problem then i will deal with it.
I have been hearing that the pro bed 2000 bedding compound is the best??
any coments on that?

it would seem the real pro's like the davcon steel ?
so i dont know but from what i have been hearing i think i will try the pro bed.

 

[BoydAllen]

My benchrest rifles are glued. The rest have pillars, or are conventionally bedded. If a field rifle shoots well enough, I tend not to to mess with it any more than I have to. One of my bench rifles had been pillar bedded, properly (I think), in an old 40X rimfire prone stock. Later, Kelly McMillan was kind enough to give me a prototype EDGE stock, and gave me the option of glue or pillars for the 722 action. Since I knew that the work would be correctly done, by a man with a lot of experience, I opted for a glue in. Based on how it shoots, i am glad that I did. If I had fixture to properly locate trigger pin removal holes in stocks, I would probably glue an all my Remingtons, because IMO the main fault of factory actions is not their lack of stiffness, but their lack of bedding area, and while pillar bedding does address this issue by allowing higher unit loading on the available bedding area, gluing the action to the stock, when ever practical, would seem to be a step up. I should add that in cases where higher recoil and/or rough handling would be an issue, I would take do as the late, great Lee Six once suggested, and pillar, and then glue, and then torque the action screws as if not glued, a belt and suspenders approach.

 

[Steve Blair]

Do your glued BR rifles have recoil lugs or does the glued surface provide enough shear?

 

[BoydAllen]

My Viper, in 6ppc does not have a lug. My .222 that is built on a 722 action was barreled to be bolted in, and so it has a lug, that it does not need. The glue would be enough.

 

[Frankr]

boyd i beg to differ, the viper action has a recoil lug, the rear tang is the recoil lug.

 

[BoydAllen]

Yes, i am aware of that, I suppose that I was addressing the use of a lug between the face of the action and barrel shoulder. Jerry Stiller fly cuts the bottoms of his aluminum actions to significantly increase the surface area, and that, in combination with their being hard anodized makes for a very secure glue job. for the actual glue in, I believe that he uses a type of epoxy that is sold for attaching golf clubs' heads to their shafts. Evidently it is a good choice for this application. I have had no problems, and IMO, for this caliber, no lug, including the back of the action, would be required. If I screw in a larger caliber barrel, I may be glad that it is there. (and wish I had a stock with a larger butt, and something besides a sharp cornered aluminum butt plate