Re 80% lowers

[AreWeFree]

Well heck, I just now got the smarts and looked it up on youtube. I didn't realize I'd need a jig to do the mill work. What's another $150 eh? Oh well, it was just a thought. Thx anyway guys!!

Tactical Machining is having a sale at the moment, pick up a jig for $64 if you need one: http://www.tacticalmachining.com/80-...jig-gen-2.html

[Eljay]

Well heck, I just now got the smarts and looked it up on youtube. I didn't realize I'd need a jig to do the mill work. What's another $150 eh? Oh well, it was just a thought. Thx anyway guys!!

This isn't something to do because it makes financial sense. It's a fun project. Which would be the one argument to get polymer - if you just kind of wanted to hack something together just because you can and then run it with a .22. Aluminum if you want actual pride of ownership, etc.

[CK_32]

Tactical Machining is having a sale at the moment, pick up a jig for $64 if you need one: http://www.tacticalmachining.com/80-...jig-gen-2.html

Why so cheap?

I wonder how well those work.


I used a JT, $160 MSRP IIRC. I wonder what the difference is. Might have my buddy jump on this if it's on the up and up.


Anyone?

[AreWeFree]

Why so cheap?

I wonder how well those work.


I used a JT, $160 MSRP IIRC. I wonder what the difference is. Might have my buddy jump on this if it's on the up and up.


Anyone?

Wow, that JT jig looks great...

The side plates of the TM jig do not bolt together, it's oriented by the takedown pin holes of the receiver and affixed using 2 bolts through the top plate. I also think it's aluminum with steel bushing inserts for the safety selector and fcg pins.

One problem I can see with the TM jig, is that you can't scribe an outline using a top plate, then remove the top plate to do the cutting. You'd have to have the side plates secured in a vice to do that.

The JT jig is definitely higher quality, no question, but I'm hoping the TM will get the job done.

[tackdriver]

Get aluminum. Poly's are still too hit & miss from what I've read. And jigs are for people that don't know how to use the proper measuring tools, or to increase production in volume. You don't need a jig to cut a lower or two.

That's kinda what I was thinking but I cant find anyone on you tube who doesn't use a jig. I would like to see the process without one. It looks to be just drilling and carving out the mag well???? I assume, other than the drill bits, I would need a milling bit to use in my drill press. I am hardly a perfectionist so a glich or two on the lower wouldn't bother me. Putty and superglue are my best friends!!!

[AreWeFree]

That's kinda what I was thinking but I cant find anyone on you tube who doesn't use a jig. I would like to see the process without one. It looks to be just drilling and carving out the mag well???? I assume, other than the drill bits, I would need a milling bit to use in my drill press. I am hardly a perfectionist so a glich or two on the lower wouldn't bother me. Putty and superglue are my best friends!!!

You're milling out the FCG pocket, and the reason for a jig is so you can keep the part level, lock the part in place while working, and it provides top plates so you have a template and don't need to make all of the measurements, just need to measure depth.

[tackdriver]

Yes, I understand that. Im just hoping/thinking I can get away without having to buy any jig. Like I say, I don't need perfection, just functionaility. Every how to site I find all use a jig.....

[stix213]

Anecdotal evidence from people I know who have completed 80% poly lowers is they will eventually snap just forward of where the buffer tube attaches with anything beyond light range bench shooting. If you're rough at all with your guns, or do any running around with them, expect it to break eventually.

[AreWeFree]

Yes, I understand that. Im just hoping/thinking I can get away without having to buy any jig. Like I say, I don't need perfection, just functionaility. Every how to site I find all use a jig.....

I'm sure you could figure it out just fine then. Go take an existing lower and make all of your measurements then scribe your 80% and start cutting. There are several threads here which show what it will look like once it's done.

[12voltguy]

Not trying to niggle, just want the facts correct.

There are...

Machined forged lowers of either 6061-O or T or 7075-T.
Machined billet lowers of either 6061-O or T or 7075-T.

A forged lower will be stronger than a billet.
7075 will have higher tensile strength than 6061.
6061 will be more corrosion resistant than 7075.
6061 is weldable, 7075 is generally not thought of as weldable, some have been successful with minor repairs.
I believe all Military M-16s are 6061. I know older M-16s are.

Machined billets can have many nice features or details programmed into the CNC machine and the final product.
Forged lowers generally follow the blueprint mil. spec. standard.

Any Aluminum lower you chose is GTG!

don't forget the CAST ones
I have a few unfinished

[-hanko]

What about those ATI Omni Hybrids? I myself will stake my Cav 15 complete lower against any aluminum or forged lower.

The "ATI" would be enough to make me very wary.

The only plastic lower with a reliable history is Cavalry Arms'.

Anecdotal evidence from people I know who have completed 80% poly lowers is they will eventually snap just forward of where the buffer tube attaches with anything beyond light range bench shooting. If you're rough at all with your guns, or do any running around with them, expect it to break eventually.

The general vibe here has changed from moist-with-anticipation for the Plum Crazy POS lowers, to the same with Ares' lowers, to kind of the same except for .22LR only.

Given that the AR was designed with aluminum as the material, to me it's ludicrous to think you could change something as basic as the raw material and not have problems.

Plastic lowers here are popular since anybody can finish one without machine tools, but you get what you pay for.

Again, the only plastic lower with proven reliability is from Cavalry Arms, and they don't make an 80%-er.

I'm sure you could figure it out just fine then. Go take an existing lower and make all of your measurements then scribe your 80% and start cutting. There are several threads here which show what it will look like once it's done.

AR blueprints with dimensions are all over the web.

[Cannon-Arms]

Not trying to niggle, just want the facts correct.

There are...

Machined forged lowers of either 6061-O or T or 7075-T.
Machined billet lowers of either 6061-O or T or 7075-T.

A forged lower will be stronger than a billet.
7075 will have higher tensile strength than 6061.
6061 will be more corrosion resistant than 7075.
6061 is weldable, 7075 is generally not thought of as weldable, some have been successful with minor repairs.
I believe all Military M-16s are 6061. I know older M-16s are.

Machined billets can have many nice features or details programmed into the CNC machine and the final product.
Forged lowers generally follow the blueprint mil. spec. standard.

In my opinion, any Billet or forged Aluminum lower you chose is GTG!

I clarified my opinion above, noted in red.

[Cannon-Arms]

don't forget the CAST ones
I have a few unfinished

I purposely left them out of my little ditty above. The strength of castings is somewhere just a notch better than polymer. both far weaker than the forged or billet lowers.

I suppose I should have made that clear in my last sentence from my post above.

[2GQ4U]

Not trying to niggle, just want the facts correct.

There are...

Machined forged lowers of either 6061-O or T or 7075-T.
Machined billet lowers of either 6061-O or T or 7075-T.

A forged lower will be stronger than a billet.
7075 will have higher tensile strength than 6061.
6061 will be more corrosion resistant than 7075.
6061 is weldable, 7075 is generally not thought of as weldable, some have been successful with minor repairs.
I believe all Military M-16s are 6061. I know older M-16s are.

Machined billets can have many nice features or details programmed into the CNC machine and the final product.
Forged lowers generally follow the blueprint mil. spec. standard.

In my opinion, any Billet or forged Aluminum lower you chose is GTG!


I clarified my opinion above, noted in red.

Very informative post. Thanks!

I bought several forged lowers a couple of years ago for $60 apiece and always assumed that billeted was a higher end product based solely on the price difference.

[Germz]

I finally decided to do one before it's too late. Is there any pro/con between an aluminum lower vs a poly? Do all makers require the same type of prep work or are some easier than others?

Thx!!

before it's too late? do you know something we don't?