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Eye Master
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Discussion Starter · #1 · (Edited)
So I was horsing around, trying to figure out how to make a metal chassis that will integrate into either a wood or fiberglass stock to give rock solid bedding with less mess than a full glass bedding job.

This is work in progress, I'm still thinking over the front bedding surfaces by the stock liner, but as I was noodling it, it occurred to me that the rear surfaces are relatively easy to do.

I took an old stock and routed the rear, under the receiver contact points, and then cut all the way through and completely removed the trigger contact surfaces.



I then machined up an aluminum pillar that goes all the way from the bottom, up to the receiver as a monolithic block. No wood in the equation, other than it will eventually get epoxied to the wood.







I'll have the first example with me at Camp Perry next week, if anyone wants to stop by and look at it.

Not sure how to execute it. Maybe I make it in 4 sizes - +0, +0.005, +0.010, +0.015, so you can get your exact fit. I also need to get drawings or a template, or some sort of guide, so people can route their stock to fit.

Another idea is that I could make a plug that either holds a switch, or else just fills in the hole for the selector. That is in the future.

We'll see where this goes. Dunno pricing yet. I just bought a new VMC, and once I get it set up, I ought to be able to spit these out fairly easily.
 

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Seems to me you wouldn't need to make but 1 size for it to work. Possibly make it on the long side and cut the trigger latch slot a little deep and the end user could file to fit.

Now if you come up with a set for the front that will replace the stock liner and give pads for the trigger group to rest on, you will be on to something. Sort of like a bedding job where taking it apart won't lead to it breaking down. I'm sure that will be trickier but not by much.

If I were so inclined I think I would make a casting of the bedding surfaces of an action and use that to mill the bedding surfaces from receiver rail to trigger pads. Route out the stock, drop in and epoxy. Glass bedding would be history.
 

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Eye Master
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Discussion Starter · #4 ·
You are not far off my thought process. I don't need to cast a receiver - I have the drawings, so the general plan is exactly that I will make a machined replacement for the stock liner that will have pads for the trigger and for the receiver.

Yes, it would be great if I could get a precision machined surface top and bottom. The only issue is that the lugs on the trigger guards sometimes wear, so how tight a trigger pulls up an action can vary. I'd love if I could make the pads slightly adjustable. I have an idea how to do that nicely for the rear pillar I just showed, but short of adding shims on top, all other adjustable ideas I have drive me away from the monolithic design, which I think if cool.

Maybe I just make them all 0.020 oversize, and you sand it to fit.

The other nice thing is that with the aluminum pillar, I can add a stop screw for the trigger, so if someone wants overtravel limits, I can do that.
 

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Why not just an entirely monolithic block from the front of the receiver to the heel?

Would simplify the routing of the stock for certain. Make it like a Troy or other aluminum stock with thinner walls that will allow a wooden stock to be the visible surface. There is plenty of room in a match profile stock for it. Probably enough wood in the forend to extend it all the way out to the stock ferrule. Completely eliminate the problems of bedding consistency and draw pressure present with wood stocks.

Just spitballing but fitting a switch into that would be a piece of cake.
 

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Eye Master
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Discussion Starter · #6 ·
That was my starting thought, but it's not that easy. Up front, the pads for the receiver extend nearly to the outer edges of the stock, similarly the trigger pads extend nearly to the outer edges. If the entire block is monolithic, one of those pads needs to be routed full depth, so if the block is inserted from the top, the trigger pads need to be routed from the top right through to the bottom. If you try and insert from the bottom, you have the same problem in the other direction. At the end of the day, with a monolithic design there will be a spot in the stock where all but a paper thin layer has been routed out. Since I want to make these to sell, rather than me trying to route people's stocks for them, counting on people to route their stock that thin without a CNC machine will result in a lot of ruined stocks and upset customers.

So I need a more clever design. Maybe this is why no one has done it yet ....
 

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You should rephrase your opening line from "horsing around" to "tinkering".

In my opinion a "Tinker" is someone who can take a well made, well designed piece of equipment and think (tink) up ways to make it better.

You, Sir, are a "Tinker".

Another term comes to mind but the term has been hijacked by the illegal drug meth heads.

The term is "Tweaker".

My definition is; someone who can fine tune (tweak) a piece of equipment to get the maximum results out of it.

As an Electrical Technician, I use a small 1/8" pocket screwdriver "tweaker" to tweak speed potentiometers, photoelectric eyes and any other adjustable devices to get the most out of our machines. Now more recently I use the laptop and a PLC.

I will respectfully consider you a "Tinker".

Amazing things you are doing.
 

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Well, BPT and Tank's rifle shop have made one piece, fitted stock liners out of steel. Does your idea have anything in common with these liners? Or benefits over the liners?

Sounds like you are on to something good. Especially if they are easier to obtain and install than the xm25 type liners.
 

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Excellent idea

Hello Art N.

This is an exciting new concept, are you planing to use a screw with the Pillar? May well do away with those ugly rear Lugs, please put me on the buyer's list... I have additional ideas for a super duper shooter...Art L.
 

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Looks very interesting... I can't help but wonder what a product like this combined with the carbon fiber stock another member of this forum produces would be like in terms of accuracy potential. It makes me think that this pillar could molded/fused into the carbon fiber stock such that they were inseparable basically offering a chassis like fit of the action combined with the form factor of a typical M14 wood/fiberglass stock. Hmmmm.
 

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That was my starting thought, but it's not that easy. Up front, the pads for the receiver extend nearly to the outer edges of the stock, similarly the trigger pads extend nearly to the outer edges. If the entire block is monolithic, one of those pads needs to be routed full depth, so if the block is inserted from the top, the trigger pads need to be routed from the top right through to the bottom. If you try and insert from the bottom, you have the same problem in the other direction. At the end of the day, with a monolithic design there will be a spot in the stock where all but a paper thin layer has been routed out. Since I want to make these to sell, rather than me trying to route people's stocks for them, counting on people to route their stock that thin without a CNC machine will result in a lot of ruined stocks and upset customers.

So I need a more clever design. Maybe this is why no one has done it yet ....
I don't think it would be necessary to have it be the full width of either the stock or trigger pads. Just enough thickness to give it rigidity to not twist when it encounters forces of recoil, sling or wood movement due to humidity and temp. I am not a metallurgist by any stretch but there are a lot of places on an AR receiver less than 1/4" thick and they are pretty rigid. The wood under the pads would have minimal influence, I think.

Think of bedding pillars in a bolt action stock. They do the job and are only supporting a part of the action as well the rest is supported by the wood.

It wouldn't be easy to machine I am sure but you could do a jig like Modulus Arms does for AR lowers and route out the inletting with a laminate trimmer and a 1/4" end mill. The routing wouldn't have to be super precise either if the receiver overhung the bedding block by a touch where you wouldn't see the epoxy binding the block to the wood anyway.
 

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Eye Master
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Discussion Starter · #13 ·
Hello Art N.

This is an exciting new concept, are you planing to use a screw with the Pillar? May well do away with those ugly rear Lugs, please put me on the buyer's list... I have additional ideas for a super duper shooter...Art L.
So now you know why I was all hot to buy that used McMillan stock from you ... so far I have been working on scrap/repair wood stocks until I get comfortable enough to cut into a $500 stock. But it will end up in the McMillan, along with a new stock liner I'm developing.

I had a discussion about your question today - do you (a) use a gage block to do a precision alignment to the stock, and then force the receiver to conform, or (b) do you put it in allowing some float, and clamp it between the receiver and the trigger, and let the pillar find it's 'happy place' while the epoxy sets?

I am convinced the latter, (b), is the better option. The important surfaces in the stock are the rear of the lugs on the stock liner. So if you put this rear pillar in loose and let it float to the receiver you don't risk creating any warping or twisting on the receiver to compromise the contact with the stock liner.

I have two of these made in time for me to take them as show/tell to Perry later this week. So I don't think it likely I have more before about 2 weeks from now, when I get back, but after that I'll get on it.

As to rear lugs, my brain is trying to focus on one concept at a time. I think the pillar could be modified with a pocket to accept a rear lug. I'd have to look at how many people do rear lugs and what all the designs are.
 

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What stared off as a monolithic full length bedding block took a side trip into something completely new and interesting.
Keep up the good work.

But keep the monolithic full block in mind. Perhaps the full block is not suitable for customer. Do it yourself, so instead remove the customer completely from the tricky installation process. Instead think of an EXCHANGE program ... customer buys one of your finished/inletted stocks and you give credit for the replacement stock he sends in. IMMEDIATE GRATIFICATION!

Or, if a special stock is involved (matches the rifle, collectible, too pretty or "dad used in nam" or whatever) the customer sends the stock in for FACTORY installation ... and has to wait for the usual shop turn around times.

Both ways you have total control over quality of workmanship ... which will minimise warranty issues.

Minmises inventory, you only need a few sticks on hand with constant resupply coming from customer trade ins.

Same deal as circular saw blades at the hardware store.

PS: IMHO the full monolithic bedding blocks are probably better suited to NEW CONSTRUCTION. Laminating layers of different colored wood with expoxy over and around the alloy block for an all new stock. Or as already mentioned, an alloy bedding block could be the foundation around which a composite/ carbon/kevlar/ plastic / whatever outer shape coukd be formed. And the outer shapes are limited only by your imagination.
Very COOL!!

The word is SERENDIPITOUS.
 

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It would be nice if you were going to sell this to do-it-yourselfers and could come up with some kind of hard template that would help the consumer make the accurate cuts.

Kind of like what you see for the AR15 receiver completion kits.

This looks like a very promising idea.
 

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Eye Master
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Discussion Starter · #17 · (Edited)
Sorry this project say on the back burner for a few months, so here are some exciting updates.

1. I had some free time on the CNC, so I had a fed dozen of the rear pillars machined up. I'll toss these on my website next week and people can start experimenting.
2. I told my tool and die guy, who is a woodworker, to install one, but killed him by saying he could not use the mill. I only let him use a drill press and a Dremel. It worked reasonably well. It wasn't pretty, but it worked.
3. The big news. I got the design for part of the stock liner done, and had it 3D printed. Picture is below. I don't want this to flex during installation, so it will be a 3 piece design. I have not made the front piece yet. As you can see, the side pieces go top to bottom and have flanges. So when you bed with these, you will get solid metal all the way between the trigger and the receiver.

I'm trying out a new machine shop, so I sent them the files and told them to make me a set while I'm at shot show, so I should have a metal sample by the time I get back.

I'm liking what I am seeing so far.
 

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Have you had the chance to test out the effectiveness of your pillar project? I was thinking of something along the lines of taking a SAI loaded in stock configuration and shooting some groups with something like FGMM (or even working up a load that that rifle seems to like), then performing the pillar install and reshooting more groups to see what sort of accuracy gains you were able to achieve?
 

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Eye Master
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Discussion Starter · #20 ·
I'm still in the design phase, so no real testing yet. Besides, I'd need to enlist the aid of a good shooter :).

There is an update to progress though. While I was away at SHOT show, I had my machine shop make me the first aluminum samples. WOW! There are some sharp edges I needed to radius to match the inletting of the stock that I had done, but all in all I got them to fit nicely in under 15 minutes.

The lock-up is brilliantly tight, just enough oompf needed to cam the trigger shut, and that was with zero fitting of the aluminum parts. I figure I want to make them slightly tall, so you can trim them to fit with a file, just to allow for worn hooks on trigger groups. Indeed, these fit good enough that I might epoxy them into a McMillan match stock I have. The beauty is that it should take minimum epoxy, because all it is doing is cementing the metal into the stock, you are not actually relying on the epoxy to build a bedding surface.











 
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