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2/21/2020 11:35:28 PM
Posted: 11/1/2015 8:57:30 PM EST
Does anyone have recommendations about these to finish an 80% lower? I've sifted through thousands on ebay and amazon and can't find what I need.

What did you use if not a milling machine?
Link Posted: 11/1/2015 9:18:45 PM EST
I always use a mill, but here some router info. Modulus
Link Posted: 11/1/2015 9:49:56 PM EST
[Last Edit: 11/1/2015 9:52:25 PM EST by alpharomeofifteen]
First- make sure your jig is router friendly. Many are not and require a milling machine. I assume you already know this but you did not say what jig you have.
Modulus Arms recommends a variable speed router. From their website:

Q: What router should I use?
A: We recommend the Ridgid R24012. There are many others we have had good results with including; Dewalt D26670, Makita RT0701C, Porter-Cable 7310, Bosch PR20EVSK and Porter-Cable PCE6430. Harbor Freight and Black and Decker have been known to have poor results. There are many that will work and the important thing is that is has a 1/4" chuck and is variable speed.

When I got my 80% Arms Jig, I bought the router they recommend: the Porter Cable PCE6430. It works fine but I think there are better ones out there. The depth adjustment is a bit cumbersome on the Porter Cable.

I order my end mills from MSC. https://www.mscdirect.com/product/details/60056785?rItem=60056785

Link Posted: 11/1/2015 10:08:35 PM EST
Thanks guys, lots of good info.
How many lowers could one bit do? I have two, and considering a .308 project as well.
Link Posted: 11/1/2015 10:22:40 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GlockPointer:
Thanks guys, lots of good info.

How many lowers could one bit do? I have two, and considering a .308 project as well.
View Quote


More than you will probably build if used properly. Good luck OP.
Link Posted: 11/2/2015 12:37:14 PM EST
Originally Posted By alpharomeofifteen:
]
A: We recommend the Ridgid R24012. There are many others we have had good results with including; Dewalt D26670, Makita RT0701C, Porter-Cable 7310, Bosch PR20EVSK and Porter-Cable PCE6430. Harbor Freight and Black and Decker have been known to have poor results. There are many that will work and the important thing is that is has a 1/4" chuck and is variable speed.


I order my end mills from MSC. https://www.mscdirect.com/product/details/60056785?rItem=60056785
View Quote


The R24012 has the best combination of desirable features that we've found.
If ordering an endmill elsewhere, be sure that it matches all the requirements (as the one you linked does) 1/4" X 4" X 1", center cutting, carbide
Link Posted: 11/2/2015 8:00:26 PM EST
Make sure to check your end mill often to see that it not coming loose, my did
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Link Posted: 11/2/2015 11:19:46 PM EST
(1.) Welcome to the sickness, GlockPointer!

(2.) I've had excellent results with the Makita RT0701C Compact Router -



It's got plenty of power, is compact enough to be easy to handle, and has a "vernier" knob that makes precise height adjustments super-easy.

I'm using it with an 80 Percent Arms Universal EZ Jig, along with the EZ Jig Tool Kit. The tool kit includes all essential drill bit sizes, along with a shortened-length end mill that works perfectly with their jig.
Link Posted: 11/4/2015 9:30:06 PM EST
What an unbelievable amount of bullshit this has been.
Got the Makita, got the 35$! bit and snapped it off twice before any work was done at all. The instant it hit turbulence it just snapped right off.
Completely over this needless fucking hassle.
I could have had three basic ARs for the money I've put into this.
The lower is still good but I AM DONE.
I'm going to find a lower and build the rifle I;ve been trying to build for months.
One million percent sorry I fucked with the 80%
Link Posted: 11/4/2015 9:34:59 PM EST
Link Posted: 11/4/2015 9:47:04 PM EST
You are not supposed to try to murder the damn thing.

It can take about 2 hours to properly mill out the lower with a router.

Link Posted: 11/4/2015 9:49:33 PM EST
Sounds like you might have been feeding too much material into the end mill at once - i.e., had the router set too deep on each pass.

I'm getting the best results by setting the router depth at around 0.05 inches (1/20th of an inch) each pass, lubricating the end of the mill with WD-40 before making each pass. This gives a very smooth cut on the relatively hard 7075 alloy lowers I'm finishing - You might be able to take slightly deeper passes if your lower is made of a softer alloy.

Naturally, you have to "swiss cheese" the lower with a drill bit before using the router on it - Attempting to use the router alone is a sure recipe for failure.

I had some problems with the end mill loosening out of the router chuck, until I used both of the chuck wrenches included with the Makita. Attempting to tighten the chuck with the pushbutton shaft lock and one wrench just doesn't give you enough tightening torque. A heavy pair of gloves helps you put more squeeze on the wrenches while tightening or loosening them.
Link Posted: 11/5/2015 11:07:17 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GlockPointer:
What an unbelievable amount of bullshit this has been.
Got the Makita, got the 35$! bit and snapped it off twice before any work was done at all. The instant it hit turbulence it just snapped right off.
Completely over this needless fucking hassle.
I could have had three basic ARs for the money I've put into this.
The lower is still good but I AM DONE.
I'm going to find a lower and build the rifle I;ve been trying to build for months.
One million percent sorry I fucked with the 80%
View Quote


People who undertake 80%ers need to be honest with themselves regarding their mechanical aptitude. These are very easy to do, but you need to be somewhat handy and have a basic understanding about how things work.
They are not for everybody, but if you are used to working with your hands, they are very doable.

Since you already have the jig, router and blank receiver, why not give it another shot? There are many people here who have done it successfully and are willing to help you out with any questions you may have along the way..
Link Posted: 11/5/2015 1:34:10 PM EST
sounds like user error to me
Link Posted: 11/5/2015 1:44:28 PM EST
[Last Edit: 11/5/2015 1:45:44 PM EST by tbonifie]
OP should have bought a mill...

This is one of those things (like reloading) that's takes a great deal of patience and attention to detail.

It's not for everyone, that's for sure.

Link Posted: 11/5/2015 3:16:10 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GlockPointer:
... got the 35$! bit and snapped it off twice before any work was done at all. The instant it hit turbulence it just snapped right off...
View Quote


This is the part that confuses me. Anybody got a clue as to what the OP is trying to say here?
I have never heard the word turbulence used in any type of machining operation. Leads me to believe that he may have been in over his head.
Link Posted: 11/5/2015 3:43:09 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By maxxx93:


This is the part that confuses me. Anybody got a clue as to what the OP is trying to say here?
I have never heard the word turbulence used in any type of machining operation. Leads me to believe that he may have been in over his head.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By maxxx93:
Originally Posted By GlockPointer:
... got the 35$! bit and snapped it off twice before any work was done at all. The instant it hit turbulence it just snapped right off...


This is the part that confuses me. Anybody got a clue as to what the OP is trying to say here?
I have never heard the word turbulence used in any type of machining operation. Leads me to believe that he may have been in over his head.


Maybe he went too fast and too deep, gigitty, with each attempted pass like one of the people above me said.
Link Posted: 11/5/2015 4:35:37 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GlockPointer:
What an unbelievable amount of bullshit this has been.
Got the Makita, got the 35$! bit and snapped it off twice before any work was done at all. The instant it hit turbulence it just snapped right off.
Completely over this needless fucking hassle.
I could have had three basic ARs for the money I've put into this.
The lower is still good but I AM DONE.
I'm going to find a lower and build the rifle I;ve been trying to build for months.
One million percent sorry I fucked with the 80%
View Quote


Dude, I'll pm you my address and I'll pay shipping and you can give it all to me. Lemme know. I'll take it all off your hands.
Link Posted: 11/5/2015 5:34:16 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By suprmatch:
Maybe he went too fast and too deep, gigitty, with each attempted pass like one of the people above me said.
View Quote


According to the OP he never even got to make a pass. But that's beside the point. My question was, what does any of this have to do with turbulence?
Link Posted: 11/5/2015 5:38:40 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By matel1ly:
Dude, I'll pm you my address and I'll pay shipping and you can give it all to me. Lemme know. I'll take it all off your hands.
View Quote


If he has made so much as one cut in the pocket area or drilled a single hole, it will need to be handled/transferred just like a finished receiver.
Link Posted: 11/5/2015 6:21:38 PM EST
No way would I put an end mill bit in my router.



Sure my PC 7518 could handle it but it ain't made for metal milling.

Kudos to ya'll who make this happen though.
Link Posted: 11/5/2015 8:58:22 PM EST
Take your time. It's not a race. It will take you several hours. If you try to get it done in an hour, you're taking too many chances.
Link Posted: 11/5/2015 9:45:14 PM EST
To clarify, the lower was drilled out with a drill press, easy enough. The jig I have had me drill 3 bigger holes for the main area instead of many smaller.

Then I acquired the Makita and the end mill bit and attempted to just barely engage the lower, I never thought this go quickly.

As soon as the bit touched aluminum it dug in and snapped off, get it? The bit broke. Snap. Twice.

It was only barely touching the lower.

I didn't think this would be a breeze but I didn't know I needed to be an artisan about hogging out some metal.

Did anyone know that you can just buy a lower ready to and don't have to do this crap anyway?
Link Posted: 11/5/2015 10:33:38 PM EST
I can't picture it.

Made my first lower with a Dremel a d hand tools. Then 5 or 6 with a drill press. Never broke an endmill.


Can you post pics of the lower in the jig and the router?
Link Posted: 11/5/2015 10:34:56 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GlockPointer:
The jig I have had me drill 3 bigger holes for the main area instead of many smaller.
View Quote


That might be part of your problem. I can't imagine removing much material with just 3 holes, regardless of their size.

What brand/model of jig are you using?
Link Posted: 11/5/2015 10:39:05 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GlockPointer:
To clarify, the lower was drilled out with a drill press, easy enough. The jig I have had me drill 3 bigger holes for the main area instead of many smaller.

Then I acquired the Makita and the end mill bit and attempted to just barely engage the lower, I never thought this go quickly.

As soon as the bit touched aluminum it dug in and snapped off, get it? The bit broke. Snap. Twice.

It was only barely touching the lower.

I didn't think this would be a breeze but I didn't know I needed to be an artisan about hogging out some metal.

Did anyone know that you can just buy a lower ready to and don't have to do this crap anyway?
View Quote
The 80% Arms Jig instructions recommends only taking 1/2 to 1/3 of a hash mark on each cut. (picture below) I have found that only taking 1/4 of a hash adds life to your end mills. Whenever I try to do the 1/3 of a hash, I end up chipping the flutes off of my end mills, but I've never broken one. There is around .200" between each hash, if you only went 1/4 hash, that's only .050" at a time. No, you are not taking very much material on each pass, but it is not a race to get done. I don't mean to nitpick your choice of words but the last thing you want to do is try "hogging" out some metal. Nibbling would be a more appropriate term.


Link Posted: 11/6/2015 12:19:08 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By alpharomeofifteen:
The 80% Arms Jig instructions recommends only taking 1/2 to 1/3 of a hash mark on each cut. (picture below) I have found that only taking 1/4 of a hash adds life to your end mills. Whenever I try to do the 1/3 of a hash, I end up chipping the flutes off of my end mills, but I've never broken one. There is around .200" between each hash, if you only went 1/4 hash, that's only .050" at a time. No, you are not taking very much material on each pass, but it is not a race to get done. I don't mean to nitpick your choice of words but the last thing you want to do is try "hogging" out some metal. Nibbling would be a more appropriate term.
View Quote


There's that magic number again.

So far, I've finished 9 lowers this way - and all of them came out perfect.
Link Posted: 11/6/2015 10:31:50 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GlockPointer:
Did anyone know that you can just buy a lower ready to and don't have to do this crap anyway?
View Quote


I find it hard to believe that anybody did not know this. Nobody builds 80's because they have to, they build them because they want to.
Link Posted: 11/6/2015 11:37:57 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By maxxx93:


I find it hard to believe that anybody did not know this. Nobody builds 80's because they have to, they build them because they want to.
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Discussion ForumsJump to Quoted PostQuote History
Originally Posted By maxxx93:
Originally Posted By GlockPointer:
Did anyone know that you can just buy a lower ready to and don't have to do this crap anyway?


I find it hard to believe that anybody did not know this. Nobody builds 80's because they have to, they build them because they want to.
That is not a totally off the wall statement by GlockPointer.......when I got into AR's, my first purchase was a jig and a lower receiver.
At that point I had no clue what was out there for parts and I would not have known what a "stripped lower" was if you asked me.
But I agree with you that we build because we want to.

Keep Calm and Build On
Link Posted: 11/6/2015 1:59:44 PM EST
I originally had issues and chipped a flute on my first attempt. After a few online conversations with Maxx at Modulus Arms, he was able to give me some tips that helped. I just finished my fifth lower this morning.
Link Posted: 11/6/2015 2:00:20 PM EST
[Last Edit: 11/6/2015 3:28:44 PM EST by LeonardS]
sorry, double post.
Link Posted: 11/6/2015 3:34:48 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By LeonardS:
I originally had issues and chipped a flute on my first attempt. After a few online conversations with Maxx at Modulus Arms, he was able to give me some tips that helped. I just finished my fifth lower this morning.
View Quote


I'm pleased that it worked out for you. I'm always glad to help out anybody with an 80% build question, whether you are a modulus customer or not.
Link Posted: 11/7/2015 3:51:38 PM EST
No I wouldn't want a bunch of aluminum chips going into my router either. I've never done a lower, but I do work with metal and most of my wood working stuff runs way too fast for metal. I use a lot of tapping fluid not WD40 for drilling metal and very light down force.

Too much RPM induces chatter, and that axial vibration tempers the cutting tool shank and that is what snaps it off. Higher speed give you a better finish but reduce tool life. Do you really need a high finish on this part of the receiver? It's not a mag well. Billet aluminum is much different than work hardened steels so you really need to understand the feeds and speeds. The tool can only remove so much material for a given speed just like the teeth on a saw blade.

Onsrud/LMT would be my first choice for a cutting tool. Onsrud is the long standing router bit supplier to industry and LMT (German company - no relation) owns them now.

Take your time. Machinists are very patient and detail oriented if this isn't you and you have to have a 80% lower, take it to a machine shop.

1/4 shanks are really lightweight so they need to be pampered a little. Know that the flutes of a cutting tool for aluminum can cut upwards toward the motor or away from the motor. Most people using these cutting tools have a preference so both are made.
Link Posted: 11/9/2015 12:46:21 AM EST
Went hunting this weekend so no progress on the lower.

It seems also that my jig might serve me better in a mill as apposed to one that might be better for the router. The top plate is right atop the receiver.

I didn't realize there was an 80% vendor? weighing in on the thread and to clarify I do not have the Modulus or 80% Arms products. I highly suspect this would go better if I did.
Link Posted: 11/9/2015 11:32:22 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Faust921:
No I wouldn't want a bunch of aluminum chips going into my router either. I've never done a lower, but I do work with metal and most of my wood working stuff runs way too fast for metal.

Too much RPM induces chatter, and that axial vibration tempers the cutting tool shank and that is what snaps it off. Higher speed give you a better finish but reduce tool life.

Machinists are very patient and detail oriented if this isn't you and you have to have a 80% lower, take it to a machine shop. .
View Quote



The router takes in cooling air from top and blows it out of the bottom. I would worry more about dust from cutting wood than I would about metal shavings getting in there. The chips get nowhere even close to the air intake and the bearing is sealed, so no worries there either.

Yes, full speed is too fast, that is why we specify a variable speed router.

The machine shop you take it to will need to have a 07 FFL in order to legally finish off the receiver and will also need to have it engraved showing them as the MFG. of the receiver.
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