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Gunsmithing Tips on Bedding an Aluminum Stock

jacq220

jacq220

Sergeant
Full Member
Minuteman
Dec 5, 2007
647
1
39
Indianapolis, Indiana
www.indygunworks.com
I am no amatuer at glass bedding, i have done several all turned out rather nice. However this will be my most difficult one yet.

Its a factory savage BAT w/ the accustock. I do NOT want to change stocks but dont really know what material i need to remove in order to get this thing properly glassed in.

Here is a photo, any advise would be great.
How much of the accu channel should i remove? what areas should i block off w/ clay completly.
How much aluminum should i remove in the rear tang area.
Whats the best method of roughing up the aluminum to assure a long lasting bed job.
I can post as many pics as needed just let me know what other views you need to give me some informed advice.

IMG_0107.jpg
 
Re: Tips on Bedding an Aluminum Stock

If it were me:

Two choices. Leave it alone or completely machine the aluminum chassis portion out of the stock.

Here's the rub. Unless you can machine in a vacuum oxygen in the air will oxidize the surface of the aluminum almost instantaneously. Epoxy doesn't like this. It'll stick for awhile, but it WILL break down and the joint will begin to fail. Especially with shock/shear loading. (just talk to an aerospace engineer that worked on the A-380 airbus. Ask about the wings delaminating from the spar)

I realize guns aren't airplanes but it doesn't change the fact that it still takes place. This is exactly why I won't use an aluminum pillar in my guns.

Just my two bits.

Good luck.

C
 
Re: Tips on Bedding an Aluminum Stock

http://www.savagearms.com/accuracy/accustock/

The video on the accustock seems to be bs free.

I was curious why thin Aluminum in a V block. It may be stronger that steel per weight, but not necessarily stiffer than steel for it's weight.

I don't know what they meant by "pre stressed" but if by that they mean that that the V that touches the round bottom tangentially is somehow pre stressed outwards, that would be a cleaver feature. But looking at it, the stress just comes from the tension on the action screws that pry the V sides outward.

They are right it is far better than concave glass bedding under a round bottomed receiver, but what isn't?

What does it all mean?

Don't put any glass in there, or you will make it heavier and might even screw it up.
 
Re: Tips on Bedding an Aluminum Stock

never been known to bed a stock, a fatty here and there but never a piece of aluminum, whatever floats yer boat though.


I'd leave it be as noted above twas me
 
Re: Tips on Bedding an Aluminum Stock

Don't remove any aluminum. If the aluminum is anodized bedding compound will stick fine. Bedding compound is in compression all you need is something to take up the gaps and hold the action stable near the front and rear action bolts,and not cause distortion when the action is tightened. Most likely it won't make a difference if your rifle isn't throwing shots. If you want to do a test spray both the stock and action with release agent and bed with JB weld around the front ring and rear tang just a light skim coat. Without removing the action after everything is cured install the action bolts and torque the down. If it doesn't make a difference take it apart and clean everything out. If it does help perform a permanent bedding job.
 
Re: Tips on Bedding an Aluminum Stock

Why do most of the threads asking for advice start off with " I know what I'm doing, but......"

Leave it, it's as good as its gonna get. You'll probably cause more harm than good trying to bed it.
 
Re: Tips on Bedding an Aluminum Stock

I assure you i have a good grasp on what i am doing. I was just making a point that this wasnt a "how to" thread as much as a "should i" thread. if i decide to pull the trigger i can absolutly do all the work myself, i am just not sure if it would be beneficial... not to much further down in this gunsmithing forum is a thread about my bolt seizing up when putting more than 40 inch pounds on the action screws. clearly there is some stress in there, even though i have yet to shoot the rifle. i prefer to have more than 40 inch pounds and would like to be able to have repeatable settings in the feild w/out a torque wrench, something i am not so confidant in at the moment. but hey, its easier to try and call someone out than help them right?
 
Re: Tips on Bedding an Aluminum Stock

It's easy to disregard most of this and whittle it down to saying "it's just a fricken deer rifle." Thankfully that position isn't taken by engineers who design stuff most of us take for granted when flying commercial or cruising around under the arctic circle.

Take it for what its worth, but this is what I learned:

I'm fortunate to have some pretty smart fellers for friends. One in particular lives in the Seattle area and makes a very comfortable living designing, developing, and evaluating fasteners for aerospace and nuclear submarine applications.

About 8 years ago I asked for his help on this very question. First, there isn't a "blanket answer" that covers everything. For the sake of this discussion we'll use a particular screw.

1/4-28 made from 300 series stainless. Popular now with many of the custom actions.

With this particular fastener you don't exceed 40 inch pounds. Period. If you do the fastener will yield because it exceeds the tensile loading capacity of the threads and you end up only chasing problems that really don't exist.

Different materials have varying degrees of lubricity, tensile strength, and surface hardness. All of which play into this.

You also must take into consideration the thread pitch. This is where friction coefficients, flank surface area, and shear angles also become important. Not to mention root diameters vs major diameter and the torsional/shear loading applied to the cylinder/shaft portion of the fastener.

Be that as it may if you sit and do the math the numbers are pretty close. One does not clearly outshine the other.

Don't forget also that the threads in the receiver are just as capable of being influenced. A kryptonite fastener is only as effective as what its being screwed into.

Excessive screw torque is attempting to mask a larger underlying problem: Poor bedding and/or incompatibility of components.

If your building a spaghetti M700 in a boomer with a barrel that resembles the axle out of an excavator in a featherweight sporter stock, then its likely the gun will perform poorly no matter how much tension is put on the guard screws.


Hope this helped.

C
 
Re: Tips on Bedding an Aluminum Stock

Chad, I was to fly to Nice (Fr.) in the near future, but now I am afraid the airfoil will cease to exist about 129 nm beyond the Azores. upon disintegration: HALO, Boeing Dreamliner regrets, or kiss my a** goodbye and dream about a deer rifle for .000125 sec... ?
 
Re: Tips on Bedding an Aluminum Stock

Chad, please go into a little more detail on this statment:

"1/4-28 made from 300 series stainless. Popular now with many of the custom actions.

With this particular fastener you don't exceed 40 inch pounds. Period. If you do the fastener will yield because it exceeds the tensile loading capacity of the threads and you end up only chasing problems that really don't exist".

I know you said 300 stainless, AND I DON"T KNOW JACK ABOUT STEEL HARDNESS, but I do know 1/4x 28 is what thread several of my rifles have.

I keep hearing 65in lbs torque for action screws. Is 65 to much stretch/stress for the factory screws or the aftermarket socket head screws?

Thanks
 
Re: Tips on Bedding an Aluminum Stock

http://www.zerofast.com/torque.htm
http://www.onlinemetals.com/stainlessguide.cfm

Just from looking at that, 40 foot pounds of torque on a 300 series 1/4-28 bolt does not look like a good idea.

I am not the engineer in Seattle Chad is talking about. I flew back to New Jersey 24 years ago and made a pitch to a submarine contractor to design some power supplies for them. I did not get a contract.
 
Re: Tips on Bedding an Aluminum Stock

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Clark</div><div class="ubbcode-body">http://www.zerofast.com/torque.htm
http://www.onlinemetals.com/stainlessguide.cfm

Just from looking at that, 40 foot pounds of torque on a 300 series 1/4-28 bolt does not look like a good idea.

I am not the engineer in Seattle Chad is talking about. I flew back to New Jersey 24 years ago and made a pitch to a submarine contractor to design some power supplies for them. I did not get a contract. </div></div>

we are talking inch pounds not food pounds.
 
Re: Tips on Bedding an Aluminum Stock

That makes me feel a bit better.... still dont like the bolt starting to bind at over 40 inch pounds but i guess i just need to get it out there and see what this thing is capable of... hopefully it will be sub MOA but this is my first experience w/ the accustock and i have to say i am not a fan thus far.
 
Re: Tips on Bedding an Aluminum Stock

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JACQ</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Clark</div><div class="ubbcode-body">http://www.zerofast.com/torque.htm
http://www.onlinemetals.com/stainlessguide.cfm

Just from looking at that, 40 foot pounds of torque on a 300 series 1/4-28 bolt does not look like a good idea.

I am not the engineer in Seattle Chad is talking about. I flew back to New Jersey 24 years ago and made a pitch to a submarine contractor to design some power supplies for them. I did not get a contract. </div></div>

we are talking inch pounds not food pounds. </div></div>

OK, 480 inch pounds would not look like a good idea for a 300 series 1/4-28 bolt.

Optimum looks like:
a) 60 inch pounds waxed [5 foot pounds with MY torque wrench]
b) 120 inch pounds plain [10 foot pounds with MY torque wrench]


 
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