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View Full Version : are billet lowers stronger than forged lowers?


sniper_jay
11-22-2006, 1:27 PM
i might buy a couple of sun devil lowers 'cause they look nicer than others. i know most lowers are purty much the same as they're all mil spec but i noticed that they claim to be "tougher than castings" how do they compare against forged lowers in toughness?

Stanze
11-22-2006, 1:34 PM
Forged lowers are stronger than billet. Billet or cast is not Mil-Spec.

ETA: Previous thread discussing this topic: http://www.calguns.net/calgunforum/showthread.php?t=42094

ivanimal
11-22-2006, 1:38 PM
Lower strength is not an issue, as it is not a part thet is under much stress. I dont know why people make such a big deal of which lower they have.YMMV.

luvtolean
11-22-2006, 1:39 PM
We don't know if that is or isn't true. I could design you a lower out of billet that was stronger than "forged".

There is far more to strength in a component than the method used to make it.

Design, alloy, heat treat, etc etc.

bu-bye
11-22-2006, 1:40 PM
Lower strength is not an issue, as it is not a part thet is under much stress. I dont know why people make such a big deal of which lower they have.YMMV.

+1. Any type of lower will work just fine.

sniper_jay
11-22-2006, 1:46 PM
i know it's not a big deal.. but i'm extremely anal about my toys. i like ones that look good. i like the look of billet lowers and was simply curious about their toughness as they advertised them as "tougher than castings." i already own 6 forged lowers of various manufacturers and just wanted a couple of billet lowers as part of my collection.

grammaton76
11-22-2006, 1:57 PM
"Tougher than castings" is precisely what they are. This is because castings are actually really bad. It's like saying, "This car is better than a Yugo!" ...well, yes, anything is.

That having been said, for practical purposes I doubt anyone's going to break their lower, billet OR forged.

xrMike
11-22-2006, 2:11 PM
...but i'm extremely anal about my toys.:eek: I really didn't need to know that. :D

xenophobe
11-22-2006, 2:27 PM
I'm sure the difference between die-forged and forged billet receivers are negligible. I'm not aware of anyone doing any hardness testing.

Besides, the hard-anodization is harder than the forged aluminum in the first place. :p

luvtolean
11-22-2006, 4:28 PM
Harder does not necessarily equal stronger.

Josh
11-22-2006, 5:48 PM
If you like the way they look, then buy with confidence.

SemiAutoSam
11-22-2006, 6:11 PM
From what Ive seen when the dye penetrant tests are done the forged receivers are much stronger as the grain structure flows thru the receiver it does not abruptly stop and then continue in another section of the receiver.

not that the lowers see as much stresses as the upper does but as far as strength the forged is much better.

The Billet receiver can at times look prettier but IMHO that's about the only benefit and they are equally the same to machine.

xenophobe
11-22-2006, 6:50 PM
From what Ive seen when the dye penetrant tests are done the forged receivers are much stronger as the grain structure flows thru the receiver it does not abruptly stop and then continue in another section of the receiver.

not that the lowers see as much stresses as the upper does but as far as strength the forged is much better.

The Billet receiver can at times look prettier but IMHO that's about the only benefit and they are equally the same to machine.


Billet receivers are usually cut from FORGED billets.

SemiAutoSam
11-22-2006, 8:56 PM
Well some manufacturers may use this type of billet but the standard use of the word billet just means a solid block not necessarily a forged billet KT Ord makes his 80% receivers out of a standard billet not a forged billet.

and in the case of a forget billet receiver what would be the benefit of using a forged billet in the first place forged is forged once its forged its no longer a billet a casting could also be forged once its forged that's all that matters as the grain structure is changed in the forging process. and that is the reason for forging any part gun, car, aircraft etc.

When you say "CUT" are you speaking of the machining process ? As cut is what one would do with a hacksaw.

Billet receivers are usually cut from FORGED billets.

xenophobe
11-22-2006, 9:11 PM
Harder does not necessarily equal stronger.

Think of what you're saying. Softer does not necessarily equal stronger either.


and in the case of a forget billet receiver what would be the benefit of using a forged billet in the first place forged is forged once its forged its no longer a billet a casting could also be forged once its forged that's all that matters as the grain structure is changed in the forging process. and that is the reason for forging any part gun, car, aircraft etc.

You get the 'talking in circles' award of 2006.



When you say "CUT" are you speaking of the machining process ? As cut is what one would do with a hacksaw.

And now I must revert to explaining rudimentary interpretations of a 'slang' term too?

*shrug*

SemiAutoSam
11-22-2006, 9:21 PM
Try addressing the points made.

Forged billet where did you read this.

what is the point of a forged billet ? What would be the benefit if the forged receiver started as a billet or a casting if the grade of material is the same grade the end result is the same.

calling the material that is forged into a receiver a billet is just a sales gimmick.

Why would you feel the need to resort to slang terms I'm sure everyone here knows what machined means.

xenophobe
11-22-2006, 9:59 PM
Try addressing the points made.

Forged billet where did you read this.

what is the point of a forged billet ? What would be the benefit if the forged receiver started as a billet or a casting if the grade of material is the same grade the end result is the same.

calling the material that is forged into a receiver a billet is just a sales gimmick.

Why would you feel the need to resort to slang terms I'm sure everyone here knows what machined means.

What is a forged receiver blank you might ask? It is a heated unforged billet that is sandwiched by a stamping die at tremendous pressure. The forging occurs from the process of using tremendous pressure and applying it to a hot piece of aluminum. The benefit of using a stamp/die-forged receiver is that it minimizes the amount of machining that is necessary to complete the item, though the structure of the metal may be more inconsistent than starting off with a standard forged billet, it is more dense and consistent than casting the same shape.

When not using stamp/die-forging... Forging a billet produces a block of aluminum that is stronger than an unforged block of aluminum that can also be machined to shape. The benefit is that the material will be more consistent and uniform in grain and structure than a die-formed forge. The downside is that it is much more costly to machine, because many usable surfaces created in the stamp/dye forging process are not available to the billet machined reciever, and takes much more time and effort to create.

As to forged billets... We're not talking fairie tales here... if you don't believe in them, you can easily search the internet for more information on why billets are often forged and the benefits of using such materials.

I thought you were a machinist Sam... Why do I have to explain to you what machining, receiver blanks, billets, forged billets, stamp/die/cold/whatever-forgings are.

SemiAutoSam
11-22-2006, 10:09 PM
You don't
The end result after the forging process is the same weather the process starts with a billet or a casting. forged is forged there is no difference as a billet is only a piece of metal "CUT" from a plate and the plate is rolled and formed when poured into a mold. if the receiver starts out as a casting its just the molten aluminum that is poured into a sand casting. they are both forged and the material still comes out with the same grain structure.

I have relatives that own a forging plant in los angeles and I worked there about 30 years ago so I'm very familiar with the process.







What is a forged receiver blank you might ask? It is a heated unforged billet that is sandwiched by a stamping die at tremendous pressure. The forging occurs from the process of using tremendous pressure and applying it to a hot piece of aluminum. The benefit of using a stamp/die-forged receiver is that it minimizes the amount of machining that is necessary to complete the item, though the structure of the metal may be more inconsistent than starting off with a standard forged billet, it is more dense and consistent than casting the same shape.

When not using stamp/die-forging... Forging a billet produces a block of aluminum that is stronger than an unforged block of aluminum that can also be machined to shape. The benefit is that the material will be more consistent and uniform in grain and structure than a die-formed forge. The downside is that it is much more costly to machine, because many usable surfaces created in the stamp/dye forging process are not available to the billet machined reciever, and takes much more time and effort to create.

As to forged billets... We're not talking fairie tales here... if you don't believe in them, you can easily search the internet for more information on why billets are often forged and the benefits of using such materials.

I thought you were a machinist Sam... Why do I have to explain to you what machining, receiver blanks, billets, forged billets, stamp/die/cold/whatever-forgings are.

ivanimal
11-22-2006, 10:13 PM
Still the question is which is stronger, my answer is it does not matter. Pick a purdy one and build away.

Solidsnake87
11-23-2006, 6:28 PM
If you honestly care, forged lowers are much stronger than billet lowers because, on the atomic level, the bonds between the atoms are being stretched and pulled slightly away from equilibrium length. These endured strains help to make a material stronger, as long as the strains have not gotten beyond the ultimate tensile strength of the material (which will never happen on a lower). Furthermore, forging aligns the crystalline grains of the material with the shape of the object making the object much stronger. Just my 2 cents if you wanted extreme detail. The forging combined with whatever heat treatment the object has endured will combine to make an even stronger object.

1hotshooter
11-23-2006, 6:57 PM
Still the question is which is stronger, my answer is it does not matter. Pick a purdy one and build away.


I agree - pick the ones you like, forged, billeted and

BUY SEVERAL

You'll be happy that you did

:cool:

Josh
11-23-2006, 9:05 PM
xeno is wrong and sam is right.

The anodizing is to guard against wear. The hardness or the surface prevents scratches and such but does not add to the overall strength of the receiver. Softer can indeed be stronger and it will yield to the the forces and bend instead of having a catastrophic failure. Think glass vs plastic for an extreme example.

As ive said before the forging process in making the shape aligns the grain structure with the shape of the item and pre-stresses the material increasing tensile strength. It works the material twice, once when the stock is created and again with it is formed into the desired shape, this has the possibility of increasing the density and uniformity of the material.

Machining it from a block of billet (forged or not) does not equal a forging. Also as i said before the grain is in one direction only and can cause the object to be weak depending on how its situated and how the loads are applied. (much like working with wood, cross vs rip cut etc).

Now there is such a thing as a machined forging, where they forge the object then completely machine the item for the best of both worlds. The strength of a forging with the dimensional control of billet. Also removes surface inclusions and imperfections. However this is not the case.

In either method it DOSENT FREAKING MATTER in the case of lowers as they do not have enough of a load applied to them in such a way as to make a difference.

Buy whichever one looks better or you think is better as either will serve you well.

uglygun
11-23-2006, 10:14 PM
In either method it DOSENT FREAKING MATTER in the case of lowers as they do not have enough of a load applied to them in such a way as to make a difference.


Only time I could see it making a difference would be in the event of a catostrophic kB.

Magazine wells tend to expand in the really bad instances of a kB. For those of us in Ca. that have registered AWs the thought of a kB is one that sends a cold chill down my back like no other.

Josh
11-23-2006, 10:31 PM
Only time I could see it making a difference would be in the event of a catostrophic kB.

Magazine wells tend to expand in the really bad instances of a kB. For those of us in Ca. that have registered AWs the thought of a kB is one that sends a cold chill down my back like no other.


From viewing pictures of lowers involved in such situations I doubt it will. In either case the lower will need to be sent out for repair/replacement. Possibly the billet lower may take it better IF they machine the area thicker but its still going to need to be sent out for repair.

Send it back to the manufacturer and ask them to make you a new one with the same serial number. They have done this before, you just need to tell them why it needs to be done.

xenophobe
11-24-2006, 12:27 AM
Billet receivers are more dimensionally consistent than any stamped receiver, and usually are machined so there is more material retained. It does not take a degree in rocket science to realize that greater mass, thicker and more consistent dimensions = improved strength.

For example, the proposed Magpul receivers will be made from 7075-T6 billets that cost over $100 each. Wanna bet that a forging will be stronger? *shrug*

And nobody has doubted that the LaRue Stealth upper is stronger than it's forged counterpart. Their ability to machine the exterior allows them to keep more material in areas where the standard forging has been known to have weak points.

Josh
11-24-2006, 12:34 AM
Billet receivers are more dimensionally consistent than any stamped receiver, and usually are machined so there is more material retained. It does not take a degree in rocket science to realize that greater mass, thicker and more consistent dimensions = improved strength.

For example, the proposed Magpul receivers will be made from 7075-T6 billets that cost over $100 each. Wanna bet that a forging will be stronger? *shrug*

And nobody has doubted that the LaRue Stealth upper is stronger than it's forged counterpart. Their ability to machine the exterior allows them to keep more material in areas where the standard forging has been known to have weak points.

Strength wise, it dosent matter.

And greater mass and thicker does not always mean improved strength. How much thicker is the receiver and where? What type of stock was used to make the billet? What did the data sheet that came with the stock say?

And if someone wanted to they could make a forging with the same extra material in those areas, its just takes a larger initial investment for a forging. But the cost over time per unit is lower vs pure CNC from billet.

xenophobe
11-24-2006, 12:34 PM
Strength wise, it dosent matter.

Right.

And greater mass and thicker does not always mean improved strength. How much thicker is the receiver and where? What type of stock was used to make the billet? What did the data sheet that came with the stock say?

Where are your tests of sheer and tensile strength of forged vs billet?

Please show me some real world analysis.


And if someone wanted to they could make a forging with the same extra material in those areas, its just takes a larger initial investment for a forging. But the cost over time per unit is lower vs pure CNC from billet.

Umm... isn't that plainly obvious. Duh.

Josh
11-24-2006, 1:35 PM
you MUST work in a gun shop xeno.

In an argument, answering a question with a question is no way to win. It is a poor attempt changing the subject and throwing the heat off yourself.

As to showing you how strong and by what degree a forging is superior to a machined billet part, that is a complex question and varies by application. So instead of trying to answer a question that could quite possibly turn in to a thesis I spent 5min on google and turned up this to actually answer your question in a general format. Now will you please answer mine regarding forges vs billet?

http://www.forging.org/facts/wwhy3.htm
http://www.sealtightsolution.com/html/cold.htm
http://www.discusscooking.com/forums/f90/knives-forged-vs-machined-21028-2.html

Omega13device
11-24-2006, 3:32 PM
Nothing like a good ol' Internet "I know more than you" match! I'll just sit back and warm my feet by the fire of this incredibly important debate. :D

xenophobe
11-24-2006, 3:52 PM
In an argument, answering a question with a question is no way to win. It is a poor attempt changing the subject and throwing the heat off yourself.

And asking questions for research without providing any yourself and just sitting back and waiting for a detailed response isn't very productive either. Any computer chair commando can say whatever they want and then ask someone else to prove them wrong.


Answers to your question?

Link to 7075-T6 data sheet:
http://www.alcoa.com/mill_products/catalog/pdf/alloy7075techsheet.pdf

Link to info on LaRue stealth billet uppers:
http://www.ar15.com/forums/topic.html?b=3&f=12&t=296350

Josh
11-24-2006, 10:41 PM
And asking questions for research without providing any yourself and just sitting back and waiting for a detailed response isn't very productive either. Any computer chair commando can say whatever they want and then ask someone else to prove them wrong.


Answers to your question?

Link to 7075-T6 data sheet:
http://www.alcoa.com/mill_products/catalog/pdf/alloy7075techsheet.pdf

Link to info on LaRue stealth billet uppers:
http://www.ar15.com/forums/topic.html?b=3&f=12&t=296350

Thats a great general data sheet for the various AL alloys but is not the one for the specific batch. Also i asked for how much thicker a billet lower is. I asked these questions because i can tell you in general about how much stronger or weaker it is if I know whats going into it and the specs.

Hell if i can dig out my old strength of materials book I can probably just copy out of it verbatim.

And ive seen the larue review. The reason they are great is becuase of QC and tolerances. NOT just because it is billet, I guarantee you that if someone took that time with a forging it would be just as good. Larue is an excellent company and i love their products because of their attention to detail. It takes massive amounts of initial capital to make a forging, and for a smaller company like larue that is already set up for CNC production it just makes sense to do it this way. Development time is quick and no extra equipment is needed the expertise is already there.

And as i keep saying, it dosent matter in the case of AR15's. The parts simply dont see enough forces for it to be a concern.

BUY WHAT BLOWS YOUR SKIRT UP!