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"Steel Bedding" ???

7410 Views 28 Replies 10 Participants Last post by  casebro
What is "steel bedding"?

I could see fitting a stock liner to the recoil lugs. And making a steel horse shoe for the rear. Then what, a steel U to support the front ? Then ummm, bed as three pieces, or build one big stock liner, that also penetrates the stock to the trigger group in three places?

A single piece of billet aluminum, perhaps? Fitted to a particular receiver, It could be bedded into a 2x4 with an ax, and shoot good groups for a looong time? Perhaps I just invented a new product? (And gave away the patent rights too?) All internal? Service rifle legal?

The thread about EBRs got me to this point, seems they claim the metal stocks are good to go right out of the box.
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I guess it depends on what context you use. When I hear the term "Steel Bedding" I usually see it referred to when someone uses steel putty epoxy like Devcon Steel Putty epoxy.

There's a guy who makes a steel bedding block. His shop is called Tank's Rifle Shop.

Tony.
 

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Steel Bed

There are several bedding compounds that include powdered steel in the mix. I have used Bisonite for years. It has stainless steel in it and it's very tuff stuff. It was the primary bedding compound used by the USAMU to bed their M14NM rifles.
 

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Discussion Starter · #4 ·
Thanks for the help guys. Just knowing to search for 'bedding block' brought up tons of new-to-me info.

Looks like Tank's block uses the saddle under the front of the receiver to hold the receiver towards the rear, rather than the GI liner that uses the front of the receiver legs. Or maybe in use he actually does 'paste bed' the front of the legs? And while Tank's has a place for the floor plate to snug against the block, his block does not extend rearward- isn't current 'paste bedding' technique to support front and rear, but not the middle? Would the rear be better supported by a steel pillar that extends through to the rear trigger group seat? Maybe or maybe not attached to the front block? eta: Maybe Tank does that?

Oh well, looks like room for variations in design. Don't know if they would be considered improvements. But I've got time, a milling machine, and steel is cheap... I think I'll check with Fred's for a junker to practice on- I need the hardware any how.

And oh, did youse guys know that in general, epoxy melts. Bedded stuff ought to be removable, maybe with one of the old fashioned copper block soldering irons.

PS, I'm not using the term 'paste' in any derogatory sense. I just don't want to use the terms too specifically: Gel, Glass, Steel, I thought 'paste' was better than goop, glop, or compound. Composite maybe?
 

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Brownells came out with their "Steel-Bed" kit in the late 80's.

http://www.brownells.com/.aspx/pid=1048/Product/STEEL_BED_KIT

It is excellent stuff AND you don't have to worry about mixing the powdered stainless steel in as it comes pre-mixed at the factory. What the "pre-mixing" does is keep the steel pretty consistent throughout the bedding so you don't get harder or softer spots from hand mixing.

It is a bit more difficult to use than Marine Tex or Bisonite, and that's the only reason I don't recommend it as much as other bedding compounds. However, once you learn how to use it, it is great stuff.
 

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The Skinny on Metal Bedding

Brownell's has marketed their Acra-Glas bedding compound for years, but professional gunnies have sort of moved away from it (I"m sure some will come to it's defense on this post, but still...) it's sort of rubbery and flexible.

Having said that, I used it myself for years as a beginning gunsmith, but then my first-effort bedding jobs were just that; smearing some excess compound in there and squeezing the action in, then later cosmetically smoothing the "results". The lack of attention to the details around the recoil lugs in, say. a Rem 700, is a telltale indicator for us more knowledgeable gunsmiths now.

What's even worse are the home-grown bedding jobs where the compound is firmly attached to the metal action (they didn't use "release wax/gel), or into the trigger group, and is not present where it should be!

To wit: you generally don't want the compound to touch the bottom, the sides, or the front, of the recoil lug. You get around that by placing some thick PVC electrical tape on the front, bottom and sides of that lug, and then injecting a carefully estimated amount of compound into the correct areas, so that the finished bedding only touches that lug on it's rear-most surface.

Then, as to compound, you really want is a very tough, heat-resistant compound that will stand up to continued recoil impact, heat, solvents, powder residue mixed with water or oils, and so on. You want it to be stable over time and big-time temperature fluctuations.

I now use Devcon Liquid Steel, or for my more particular customers, Devcon Liquid Titanium. difference? Truly, not much as far as end-game performance goes. The L. Steel has finely ground steel alloy powder, and L. Titanium has powdered, well.... guess what?

The other difference is the price per lb.: L. Steel is about $18/lb, while L. Titanium is about $70/lb at Grainger Industrial Supply. (by my memory).

The functional difference, again, is not much, although the difference may be one of the electrical reaction of dis-similar metals & therefore corrosion due to electron potential differentiasl across the metals boundary.

But the marketing difference is huge: tell an ego-driven owner if he wants his rifle expoxy-bedded with a standard compound or in... (Tah-Dah!!!!!!) TITANIUM, and that the price for "standard" bedding is about $60 - $80 for the action, versus $120 - $150 for a Titanium Bedded Action (cue the "Wagner's Flight of The Valkeries" music...) and guess which one sells the best?

(See: Webster's for Bragging Rights, Ego-Centric Behavior, etc.): !!Titanium!! wins hands down.

Of course, it is very good stuff, hard as an Unobtanium Horseshoe for a Clydesdale Horse, but still; not entirely necessary.

A good bedding job effectively minimizes or eliminates relative movement related to recoil, temp fluctuations, et al, and makes the firing dynamics consistent within the rifle's relative parts. It can negate the nasty consequences of a badly fitted, worn, loose, warped or out-of-alignment stock-to-action fit.

"AND SO!!!! Don't you dare miss our Huge Monthly Special on Extra-Strong, Ultra-Tough TITANIUM Expoxy Bedding! This month only, it's ONLY $550 for your pet rifle (shipping and handling extra of course...) This improvement will overcome bad groups, bad breath, bad marriages, and bad fuel economy on your big Gas-guzzling hog-truck! Go for it!"
GI3 GI1 DI5
 

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Discussion Starter · #10 ·
Back to the 'steel bedding block' point of the OP, this morning I spent Labor Day Laboring Away at making a steel stock liner fit my receiver legs. Not too hard, since the stock liner is soft steel. Squash each set of legs on the liner to be too tight for it's particular receiver leg, then file to get a good snug fit- the receiver legs are at a 3° taper. Get them to fit snug without the receiver legs bottoming in the liner 'slots'. Then, bend the skinny straps of the liner to get the two sets to line up as a unit.

My plan is to bed the top of the receiver to suit the draw etc at the front ferrule, then install the liner, later the trigger group. I'll probably need to slot the liner screw holes in the stock, use temporary screws during the bedding, then later make holes to suit bedding the screws to the liner.

I'm thinking the bedding's tasks can be broken down to :

1: Fore and aft recoil stability, taken care of by the liner legs.receiver legs interface.
.
2: Up/down and front draw, taken care of by the top surface.

3: Clamping pressure, done by setting the rigger group at the appropriate distance below the top.

4: Left/right yaw is taken up by the legs.

5: Left/right motion will be taken care of by the legs the bedding compound outside of the receiver legs, between legs and stock.

My bedding won't be handling the sliding of receiver removal, so I'm thinking something brown will be adequate, and less visible, rather than the Titanium stuff. As a woodworker, I learned to mix walnut sawdust into clear epoxy to make epoxy putty that matched. Hmmm, it would be softer than Brownells, but still harder than the wood stock. Hmmmm.... Or, I wonder if Home Depot sells cement tints, like carbon black, or Iron Oxide, or .... using it as filler would make my syringe of epoxy hard as concrete...

Now I just need a clunker stock to practice on. If you need me, I'll be waiting on he curb for the postman. ;)
 

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Stock works

I've inquired as to the availability of an M1A stock, perhaps damaged in manufacture, from Boyd's, on which to practice. So far, months later, no go. He said he'd try to find some, but they must not have too many rejects. I'd like to have acquired about 10 or so of them, and even asked if he could possibly machine me up some, but just the center section, but that was prohibitively co$tly.

Undt Zo Vee Prozeed!
 

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LRB junk stocks?

I've inquired as to the availability of an M1A stock, perhaps damaged in manufacture, from Boyd's, on which to practice. So far, months later, no go. He said he'd try to find some, but they must not have too many rejects. I'd like to have acquired about 10 or so of them, and even asked if he could possibly machine me up some, but just the center section, but that was prohibitively co$tly.

Undt Zo Vee Prozeed!
http://www.lrbarms.com/stocks.html
LRB is selling junk stocks for $3 each. These would be nice to practice on.

I know they are fiberglass, but hey...

Practice is practice; right?
 

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Back to the 'steel bedding block' point of the OP, this morning I spent Labor Day Laboring Away at making a steel stock liner fit my receiver legs. Not too hard, since the stock liner is soft steel. Squash each set of legs on the liner to be too tight for it's particular receiver leg, then file to get a good snug fit- the receiver legs are at a 3° taper. Get them to fit snug without the receiver legs bottoming in the liner 'slots'. Then, bend the skinny straps of the liner to get the two sets to line up as a unit.

My plan is to bed the top of the receiver to suit the draw etc at the front ferrule, then install the liner, later the trigger group. I'll probably need to slot the liner screw holes in the stock, use temporary screws during the bedding, then later make holes to suit bedding the screws to the liner.

I'm thinking the bedding's tasks can be broken down to :

1: Fore and aft recoil stability, taken care of by the liner legs.receiver legs interface.
.
2: Up/down and front draw, taken care of by the top surface.

3: Clamping pressure, done by setting the rigger group at the appropriate distance below the top.

4: Left/right yaw is taken up by the legs.

5: Left/right motion will be taken care of by the legs the bedding compound outside of the receiver legs, between legs and stock.

My bedding won't be handling the sliding of receiver removal, so I'm thinking something brown will be adequate, and less visible, rather than the Titanium stuff. As a woodworker, I learned to mix walnut sawdust into clear epoxy to make epoxy putty that matched. Hmmm, it would be softer than Brownells, but still harder than the wood stock. Hmmmm.... Or, I wonder if Home Depot sells cement tints, like carbon black, or Iron Oxide, or .... using it as filler would make my syringe of epoxy hard as concrete...

Now I just need a clunker stock to practice on. If you need me, I'll be waiting on he curb for the postman. ;)
If you do it right, all those will be combined into some other steps.

Mine would consist of:
1:prepare the stock
2:bed the liner
3:Bed the receiver (this is your 2,4 & 5 wrapped up into one)
4:bed the trigger group

I know you've read my bedding tutorial, so check post number 15 and you will see now much you can conceal the bedding job using proper taping methods. Although, if you want the bedding to exceed the outer edges of the receiver, it's a moot point. You have to look very closely at mine to tell it was bedded and you have to know what to look for.
 

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I weight in here. Using a cross between Mr Khnhusen's book and TB's guide I bedded my Tactical into an oversize stock for service rifle matches. Used Devcon steel Putty and it was not that hard after I got the nerve to rout the stock and prep it. I could not find Marine Tex any were when I did mine and settled on Devcon Steel. Watch your fore end pressure and take your time. It will really be a learning experience on the inner workings of the rifle. Good luck and have at it.
 

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Discussion Starter · #16 ·
I read all the MSDS sheets for about all of the potential compounds mentioned here. Too bad I didn't make notes.

All use some kind of chalky mineral as filler, in quantities greater than the metal fillers. Magnesium silicate, silicone dioxide, titanium dioxide. One even called it Limestone. Then the metallic colored ones also add aluminum, and a few that actually add steel, about 20%. The Titanium stuff has more steel than T, only about 10% T. Resins all seemed the same, polyamide in the 'B', and bisphenyl stuff in the 'A'. There are also some additives, for gelling and timing, and workability I presume.

I'm suspecting that the biggest difference in properties to be identifiable by the mix ratios. Since the resins actually used need to be about 5-6 to 1, the 1:1 tubes may have gone too far in making themselves user friendly, to some detriment. Like hardness or longevity. BUT that the differences under discussion may be more due to poor mixing and proportioning. Mix by weight proportions are available for several brands, but I think I'll use a triple beam scale rather than my powder scale.

I may even try my own hand at mixing clear resins with fillers and tints. Powdered silica is beach sand, probably harder than steel, and is white. It would take brown pigment well. I want wood colored, so won't dip into the can of powdered aluminum, or bronze, though bronze would be cool, eh? Like the composite that is concrete, the more filler the stronger. 90% fiber is used in some composites. I think I do have some microfibers too.

But geeze, it's 105° here today, on top of 1/8" of rain this morning. I'm staying in side for the duration.
 

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Discussion Starter · #17 ·
Hey, I mention it in another thread, but here looks good too-

Anybody try heat to remove a bedded in liner? Epoxies do go away when hot enough, especially the quick stuff. So I'm thinking the end of a hot copper rod to the liner screws will tell me if it helps, then maybe an old fashioned copper block type soldering iron inside? My research above says the glues lose strength above about 300F.
 

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Discussion Starter · #18 ·
If you do it right, all those will be combined into some other steps.

Mine would consist of:
1:prepare the stock
2:bed the liner
3:Bed the receiver (this is your 2,4 & 5 wrapped up into one)
4:bed the trigger group

I know you've read my bedding tutorial, so check post number 15 and you will see now much you can conceal the bedding job using proper taping methods. Although, if you want the bedding to exceed the outer edges of the receiver, it's a moot point. You have to look very closely at mine to tell it was bedded and you have to know what to look for.
Those weren't procedure steps, those were philosophical points as to what facet of the bedding does what towards accomplishing the overall stability.

If I can remove the liner that is in there now, my current stock would only need the fitted liner installed to where the receiver is now. Receiver to ferrule is good. Some kind of clamp to hold the liner upwards, which will wedge the legs into the slots (remember the 3°), and temporary liner screws through oversize stock holes, then wait for the bedding to harden. All done with the trigger guard clamping the rec in it's home. Later drill new screw holes in the stock to line up with the liner location.

Do you think I should have bought TWO pounds of clay? :^)
 

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http://www.lrbarms.com/stocks.html\

LRB is selling junk stocks for $3 each. These would be nice to practice on.

I know they are fiberglass, but hey...

Practice is practice; right?
Bad URL. But hell yeah, I'm sure a bunch of people would want some stocks to work on for a variety of projects. Not exactly 2x4s from your local lumber mill.
 

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Hey, I mention it in another thread, but here looks good too-

Anybody try heat to remove a bedded in liner? Epoxies do go away when hot enough, especially the quick stuff. So I'm thinking the end of a hot copper rod to the liner screws will tell me if it helps, then maybe an old fashioned copper block type soldering iron inside? My research above says the glues lose strength above about 300F.
At the RTE Shop at Quantico, we had a "heating machine" that was a copper tip on one end and a clamp on the other. It sent electric current through the item and heated up front bands or clips that had been epoxied or liners that had been bedded in place. So, yes, heat will loosen a bedded liner up. I have been using an "electified" copper soldering iron to do these things since I got it from my Grandfather's estate. With either of these rigs, we waited until there is a little smoke that comes out and then you should be able to get at least one side of the liner out, then do it on the other side. Actually, on the rig in the RTE Shop, many folks waited until there was a rather big and noxious cloud of smoke before they tried to get a glued in handguard out. Of course that was not real popular with the other RTE ARmorers. Grin.
 
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