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  #11  
Old 01-04-2021, 02:02 PM
Ted Brown Ted Brown is offline
 
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While some of my de-milled receivers have suffered notable damage to some tolerances, many have areas that were not effected. Some were saw cut and otherwise not effected at all. Some commercial receivers have issues that stand out well when compared with GI receivers. I also have prints of most all the parts including the receiver. Keep in mind that I have been working with the M14 for over 40 years.
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  #12  
Old 01-04-2021, 07:41 PM
rickgman rickgman is online now
 
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Quote:
Originally Posted by ZvenoMan View Post
Can't argue the value of a print but sometimes a 3D reference is best.
If you verify whatever dimensions you are using on the demilled part it doesn't matter what stresses it suffered.
Kind of like a go-no go gauge. It doesn't matter what it is or how it was made, if the key dimension is accurate (and it's a suitable material) then it works for that purpose.
In the warbird restoration field recovered wrecks are disassembled and many parts, clearly not airworthy are used in the same manner.

Again like the warbird field, demilled receivers have a value to some people simply because of what they were and where they may have been.

JH
Well, folks can do as they see fit but a part (assuming it is within spec) has very limited value as a dimensional model. It isn't like a go / no go gage. It only represents one set of dimensions. Part prints on the other hand represent the target dimensions, the tolerances with respecty to those dimensions and clearly define what are critical dimensions and what are reference dimensions.

Call me old fashioned but with over 4 decades of experience as a graduate mechanical engineer, my primary source of dimensional information is still part prints. Everything else is either a secondary or tertiary source.
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  #13  
Old 01-05-2021, 12:30 PM
ZvenoMan ZvenoMan is offline
 
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Quote:
Originally Posted by rickgman View Post
Well, folks can do as they see fit but a part (assuming it is within spec) has very limited value as a dimensional model. It isn't like a go / no go gage. It only represents one set of dimensions. Part prints on the other hand represent the target dimensions, the tolerances with respecty to those dimensions and clearly define what are critical dimensions and what are reference dimensions.

Call me old fashioned but with over 4 decades of experience as a graduate mechanical engineer, my primary source of dimensional information is still part prints. Everything else is either a secondary or tertiary source.
You missed the key point: "Limited Value"
If you need to physically check one (or several) dimensions in a limited production setting then demilled parts, after proper measurement and testing, as well as new parts that failed QC in some other area are often (by no means always) perfect.
No one is implying a demilled part is somehow more accurate or better than a print, nor would anyone use them for primary information, but considering their cost and durability they are often perfect for some "limited" uses.
This is exactly what has been suggested my myself and others in this thread.

JH
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  #14  
Old 01-06-2021, 10:16 AM
rickgman rickgman is online now
 
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Originally Posted by ZvenoMan View Post
You missed the key point: "Limited Value"
No, I didn't miss the point. I simply believe that it is of very limited value when a part print is of great value since it contains all of the dimensional information - including tolerances.

Of course, folks may do as they see fit.
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  #15  
Old 01-15-2021, 07:58 PM
Danny Danny is offline
 
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I use the demilled receivers for dimensional checks as well, which is fine, as long as you don't refer to the few damaged areas. In reading what some have typed here, they would make it appear as if the whole receiver was uniformly stressed and is all out of spec........in every dimension. That is a fantasy situation. There is an old saying "at some point you have to kill all of the engineers and start getting work done".
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  #16  
Old 01-15-2021, 09:04 PM
Gewehr43 Gewehr43 is offline
 
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Quote:
Originally Posted by Danny View Post
I use the demilled receivers for dimensional checks as well, which is fine, as long as you don't refer to the few damaged areas. In reading what some have typed here, they would make it appear as if the whole receiver was uniformly stressed and is all out of spec........in every dimension. That is a fantasy situation. There is an old saying "at some point you have to kill all of the engineers and start getting work done".
At times engineers understand how things are made, and others ignore them.
Which is how things get buggered...........

Anything made for an M14, has tolerances (which are shown on the blue prints/drawings), NOTHING is precisely and exactly the same.....
It's fantasy to think otherwise...........

So if you use a demilled receiver or a op rod or whatever for precise measurements you are just asking for problems.
You'll end up with out of spec parts/fit whatever because you have NO IDEA WHATSO ever whether the part you are using is within those tolerances...........
That isn't fantasy, it's fact.....

There is a reason the military made and uses specific and carefully made gauges for inspections. There is a reason those gauges are supposed to be certified each year.
There is also a reason they don't just grab another rifle and compare them, shrug "looks good" and wonder why the things won't work afterwards.

PS:
I have no idea what "dimensional checks" you might use a demilled receiver for.
But for example, it's one thing if you use it to work on rear sights, for example.
Cool, great.
Atleast check the dimensions against the drawings........
So you don't end up using a buggered part as a basis for whatever work you're doing..... so your work doesn't end up buggered too.
That's not fantasy, just common sense.
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  #17  
Old 01-16-2021, 11:55 AM
ZvenoMan ZvenoMan is offline
 
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So, you're advocating use of demilled receivers in some assembly procedures after checking key dimensions against drawing?
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  #18  
Old 01-16-2021, 02:44 PM
Gewehr43 Gewehr43 is offline
 
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Quote:
Originally Posted by ZvenoMan View Post
So, you're advocating use of demilled receivers in some assembly procedures after checking key dimensions against drawing?
If you are asking me...... No.
If you are actually making receivers, you should be using the proper drawings, using proper techniques and tools.
If you are assembling rifles, you should you use the proper specifications, techniques and tools.......
And we all know that.........

You don't need to be a troll about this.

After that I can only guess as to what the other posters here are using these demils for, as they are being coy and indirect about what they would be doing with them.
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Last edited by Gewehr43; 01-16-2021 at 02:48 PM.
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  #19  
Old 01-17-2021, 02:07 PM
Ted Brown Ted Brown is offline
 
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I work on a lot of M14 rifles. In my case when a commercial receiver has extreme fitting problems I have found it useful to compare it against a GI receiver for obvious defects or tolerance issues. I also use original government drawings for the same purpose. I use a front end to check the fit of modified connector rods when installing dummy selector kits. They make good paper weights too.
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  #20  
Old 01-17-2021, 08:43 PM
Gewehr43 Gewehr43 is offline
 
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Quote:
Originally Posted by Ted Brown View Post
I work on a lot of M14 rifles. In my case when a commercial receiver has extreme fitting problems I have found it useful to compare it against a GI receiver for obvious defects or tolerance issues. I also use original government drawings for the same purpose. I use a front end to check the fit of modified connector rods when installing dummy selector kits. They make good paper weights too.
Ok, thank you for responding.
I'd like to ask three questions, the curiosity is too much for me:
-In your first example, what issue of a buggered receiver wouldn't be shown visually or using measurements from the drawings but would be revealed looking at a receiver heel? Can you give me an example?
-Next, the "demilled" receivers I've seen all have been cut in half. The connector rod runs from the rear to front, typically across where the original receiver was cut. How do you use (or maybe connect is a better word) the two pieces of the original receiver to then use it to look at the connector?
-Finally, and for privacy, you certainly don't have to answer this: If you want a "working example" or something, why not just buy a real M14? I'm not sure when you started working on M1A's. In the 80's, when the M1A's were the king of SR, they could be bought for under 1000.00. They are about 14,000 now and I'm not sure how much real use you'd get out of it today. But that would've been a good return for a working piece, unlike any other tool you have bought.
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Last edited by Gewehr43; 01-17-2021 at 08:56 PM.
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