Demilled recievers

[lennnorment]

I saw some back halves of M14s at a local show recently. They were from real M14 rifles and not from some commercial rifles. They had been shear cut just forward of the rear sight base. Other than a paper weight, what would these possibly be good for?

[1563621]

I know many years ago there were rewelds of these. I think they had a license to do it. Now , no, really just a item to place on shelf for memories, Good & Bad!

[nf1e]

Paper weights is about the best idea for them.

[TLB]

At one show a few years ago, someone had cut off heals behind the sight ears and mounted one of each manufacturer at the quarter hour, making a custom clock.

[Random Guy]

I have 4 heels, one from each manufacturer. I wish James River Armory was still offering to make civilian receivers out of them (ATF-complaint) - but they quit doing that a couple of years ago, so my de-milled heels are just sitting on a shelf gathering dust....

[Ted Brown]

I have several receiver demills. I use them as a reference when checking tolerances on commercial receivers.

[rickgman]

Originally Posted by Ted Brown

I have several receiver demills. I use them as a reference when checking tolerances on commercial receivers.

Ted, I would be concerned that the huge mechanical stresses imparted on the receiver when it was sheared in two would deform the remaining piece to the point where it would not be useful as a reliable reference for dimensions. A part print would be far more reliable and would also give the tolerance range - not just the dimension of the speciic part in your possession.

[ZvenoMan]

Originally Posted by rickgman

Ted, I would be concerned that the huge mechanical stresses imparted on the receiver when it was sheared in two would deform the remaining piece to the point where it would not be useful as a reliable reference for dimensions. A part print would be far more reliable and would also give the tolerance range - not just the dimension of the speciic part in your possession.

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

[rickgman]

Originally Posted by ZvenoMan

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.

[ZvenoMan]

Originally Posted by rickgman

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