Cast Vs. Forged AR lower

[RImike]

I'm trying to wrap my head around how the process of the lower is made. I understand how cast is made pouring molten aluminum into sand molds, but I tried finding a forging video online, but all I get is comparison videos of forged vs cast lowers, not the process that goes into them. I have access to a kiln and sand to make aluminium parts, so I've been thinking about making a cast AR, just wondering what goes into making forged lower

 

[mclina]

This is a video of a golf club head being forged. They take a hot chunk of metal and slam it into a mold to make the shape.

 

[7.62x39]

Cast is crap. The only cast lowers ever made were used on entry level rifles. Nobody even makes a cast lower anymore, that ought to tell you something.

 

[mclina]

Cast is crap. The only cast lowers ever made were used on entry level rifles. Nobody even makes a cast lower anymore, that ought to tell you something.

There are a bunch of us that got into a Rockethub campaign for billet lowers, and the guy making them has switched to cast. Everybody is pretty pissed off.

Edit: Here is their facbook page. They delete any post that criticizes them.

https://www.facebook.com/thegun.vaultllc

 

[exo]

There are a bunch of us that got into a Rockethub campaign for billet lowers, and the guy making them has switched to cast. Everybody is pretty pissed off.

Edit: Here is their facbook page. They delete any post that criticizes them.

https://www.facebook.com/thegun.vaultllc

Yikes. Why would anybody start making cast AR lowers nowadays?

 

[7.62x39]

There are a bunch of us that got into a Rockethub campaign for billet lowers, and the guy making them has switched to cast. Everybody is pretty pissed off.

Edit: Here is their facbook page. They delete any post that criticizes them.

https://www.facebook.com/thegun.vaultllc

That whole mess had scam written all over it, that's why I steered clear. The FB page says that you have the option of a refund, GET IT.

 

[dnepro-mike]

process of forging compresses crystalline structure of the metal making it denser and therefore harder and stronger

even exactly same aluminum alloy in cast form will be significantly weaker than exactly same alloy in forged form.

it takes a big ass machine to forge aluminum lowers. not something you can put together in your garage easily.

however if application is only 22lr or similar then cast lower would suffice, assuming you not going to abuse it.

 

[mclina]

That whole mess had scam written all over it, that's why I steered clear. The FB page says that you have the option of a refund, GET IT.

I have asked to be put on the 'refund' list. They have already said that they are out of money, and cannot give refunds to anyone until they sell the lowers that the refundees do not want. First they have to make them, then they have to convince some other shmuck to buy them. I'm not holding my breath.

 

[Tommy Gun]

Yup, I lost a job because the Expert couldn't wrap his head around what I was saying. He is a master gunsmith and said cast is equal to forged. Maybe a cast AR lower is fine but I would pick a forged.

process of forging compresses crystalline structure of the metal making it denser and therefore harder and stronger

even exactly same aluminum alloy in cast form will be significantly weaker than exactly same alloy in forged form.

it takes a big ass machine to forge aluminum lowers. not something you can put together in your garage easily.

however if application is only 22lr or similar then cast lower would suffice, assuming you not going to abuse it.

 

[Gammon]

I've used cast frames and slides in 1911s and clones and can't tell the difference from forged as far as reliability is concerned. The same goes for AR lowers, although my Stag forged lower is a lot prettier.

 

[dnepro-mike]

I've used cast frames and slides in 1911s and clones and can't tell the difference from forged as far as reliability is concerned. The same goes for AR lowers, although my Stag forged lower is a lot prettier.

cast aluminum is not same as cast steel.
i think everyone who do not possess at least basic knowledge of material science should restrain from offering their opinion.

although forged steel pistol frame IS stronger than cast pistol frame; overall structural integrity of a steel as a material has much higher margin of strength (even in cast form) than aluminum does. that is why same type of parallel can not be drawn for aluminum as it could be for steel

aluminum has only 1/3 of EM (elastic modulus) of even mild steel. not to mention that aluminum alloys unlike steels do not have fatigue threshold. meaning: there is no lower limit under which application of cyclic stresses to the part will not cause fatigue failure. aluminum experiences fatigue in an entire range of stress load from micro to macro. while steel (because of it has such threshold) can be designed in ways (made thicker) until such applied load will not reach that threshold. as a result part will be able to withstand such cyclic stress indefinitely w/o compromising structural integrity.

aluminum is a material has some unique properties which can be bliss and a curse. that's why an engineer need to know material science in order to design well or make proper choice of material for intended application.

 

[Archilochus]

.... I've been thinking about making a cast AR,

Bronze - that would be very nice

 

[Boris]

I've been casting Ali for a while, the making of the cast as well as proper heating, degassing, mold pre-heat, gating, Ali alloy composition and pouring of aluminum could be very crucial, especially on a smaller parts of gAyR lower. Metal cools as it flows, it shrinks ... It can be done, but quality can vary, depending who does it and how. ARs are for girls anyway.

 

[Greschner 4]

With respect to golf, the difference in feel between forged and cast is NIGHT AND DAY!

 

[slap shot]

The latest update on that fb page states they are indeed doing forged, not cast.

Also, as a point of correction, the blanks we are using are technically forged blanks. The casts were not of sufficient quality and took too much machine time to clean up. So we switched to forged blanks. They are, as we stated, lab verified 7075 T6 aluminium alloy.

 

[RImike]

Bronze - that would be very nice

I actually might give it a go, I have (5) 5 gallon buckets in the basement full of bronze marine hardware that I have replaced on customers boats over the years. Though heavier, with some polishing, it would be very nice.

 

[Archilochus]

I actually might give it a go, I have (5) 5 gallon buckets in the basement full of bronze marine hardware that I have replaced on customers boats over the years. Though heavier, with some polishing, it would be very nice.

If you do one in bronze - I need to see some pics!

 

[mac1911]

I think if the cast ar 15 lower could be made to work ruger would have done it years ago
http://www.ruger.com/casting/P-Overview.html they are cast masters after all.

 

[Archilochus]

I actually might give it a go, I have (5) 5 gallon buckets in the basement full of bronze marine hardware that I have replaced on customers boats over the years. Though heavier, with some polishing, it would be very nice.

BTW - I have the assorted tooling for a "0%" lower - you're welcome to borrow them for the job (buffer tube tap, grip-screw tap, #drills & reamers, long bolt-stop drill).

If you cast up more than one - I might be interested in one

 

[Gammon]

cast aluminum is not same as cast steel.
i think everyone who do not possess at least basic knowledge of material science should restrain from offering their opinion.

although forged steel pistol frame IS stronger than cast pistol frame; overall structural integrity of a steel as a material has much higher margin of strength (even in cast form) than aluminum does. that is why same type of parallel can not be drawn for aluminum as it could be for steel

aluminum has only 1/3 of EM (elastic modulus) of even mild steel. not to mention that aluminum alloys unlike steels do not have fatigue threshold. meaning: there is no lower limit under which application of cyclic stresses to the part will not cause fatigue failure. aluminum experiences fatigue in an entire range of stress load from micro to macro. while steel (because of it has such threshold) can be designed in ways (made thicker) until such applied load will not reach that threshold. as a result part will be able to withstand such cyclic stress indefinitely w/o compromising structural integrity.

aluminum is a material has some unique properties which can be bliss and a curse. that's why an engineer need to know material science in order to design well or make proper choice of material for intended application.

Thanks for the "heads up". Does this mean that the cast AR lower that I have used for the last 15 years with no problems whatsoever is a POS?

 

[RImike]

If you do one in bronze - I need to see some pics!

I'm still in the planning stages, trying to figure out if I could smelt bronze in the furnace or not, not to mention I'm going to have to smelt out the impurities in it first. I think that's the first stage, smelting out anything that isn't bronze.

 

[7.62x39]

Thanks for the "heads up". Does this mean that the cast AR lower that I have used for the last 15 years with no problems whatsoever is a POS?

No, but an aluminum casting will always be inferior to a forged or billet part. If the manufacturers thought that a cast receiver was equal in strength and durability to a forged/billet piece they would still be making them.

 

[Coyote33]

No, but an aluminum casting will always be inferior to a forged or billet part. If the manufacturers thought that a cast receiver was equal in strength and durability to a forged/billet piece they would still be making them.

I would go one further and say billet is inferior to forged. Don't they forge things FROM a billet?

You can keep the billet crap, though some "look nice".


Maybe I'm a little biased, having seen what they do here:
Wyman-Gordon
Forging & Manufacturing

I've seen some HUGE aircraft engine pieces made of titanium which you could actually PICK UP.

 

[Gammon]

No, but an aluminum casting will always be inferior to a forged or billet part. If the manufacturers thought that a cast receiver was equal in strength and durability to a forged/billet piece they would still be making them.

If the "inferior" part does the job, is it really inferior? I am not aware that the manufacture of cast aluminum has ceased in favor of billet, i.e. machined, and forged lowers. Is this really true?

 

[dnepro-mike]

i would like to see your cast lower. i'm very interested, never seen one before. if you don't mind can you post some quality pics of it?

 

[RImike]

I'm still in the tooling phases of making the plug to then make the mold. I will post an update when that's done. I also have to smelt the bronze to see if it's quality is high enough and to make a flat stock out of it to see how hard it is, I might have to add some tin and zinc to it to make it harder.

 

[7.62x39]

If the "inferior" part does the job, is it really inferior? I am not aware that the manufacture of cast aluminum has ceased in favor of billet, i.e. machined, and forged lowers. Is this really true?

Yup, No one offers a cast receiver anymore, at least as far as I'm aware of. As far as inferior goes, I have seen more than one pic of cast receivers with the pivot pin boss broken off, I have never seen (or heard of) a forged or billet receiver broken in this manner.