So I milled out my 4th and final 80% lower today.
As luck would have it, the lpk I ordered last week was waiting in a box by the gate.

I had to do a little fitting with the rotary to clearance the trigger and hammer. Lesson learned there was "don't be timid on the profiling op".

After assembly, a bit of discouragement came from function testing.
The trigger was extremely tight. Like 20lbs pull tight at a modest guess.

I started to get concerned, and just about posted a new thread about it... until...

I tried the search feature on the forum and was thoroughly disappointed that it only went back 30days/50posts...
Did not find anything there...

Did a Google search and sure enough found some answers...
On ar15.com lol.

Apparently... these things like to be lubed up before they get played with...

A few drops of 3-in-1 in the action slicked it up real nice. Im guessing im somewhere around 5-7lbs on the trigger now with the absolutely crispiest function I have ever felt on an ar.

Full blown addicted now.





Never trust Mazatrol to auto plug feeds and speeds for cutting aluminum with a 4fl em.



How about this action...
And i know I just dry fired... doesnt bother me.

https://www.youtube.com/watch?v=b9sFof8KF1c&feature=youtube_gdata_player

Nicely done.

And wouldn't you know it...
Just like building trucks, there are a hundred million choices for every little part on the thing.

that's the fun of it

I find the chips don't weld to the shank if you use a mill with flutes longer than the maximum depth you mill.

I made the mistake of trusting Mazatrol.
Was cooking a little hot with that 4fl TiN coated em. Very light passes. I was only dropping .020 per pass.

I did the 4th one back on the knee mill... had dug around the shop and found a couple 2fl hss em's and had the best cutting results so far.


I dont usually work with aluminum... so out of excitement and "i want it now!" Syndrome I just used what i had in the tool magazine.
I normally work with L80 and P110 steel. Typically 4130 is in my machines.

Plus I didnt give that 4fl em any coolant lol.

Ive found that milling aluminum with a solid aluminum rod isn't as effective as other methods.

I don't see the back cut groves in the lower floor for final tolerancing, looks like you just went forward cut on the whole process.

Do you have a picture handy you might share for comparison?
I basically roughed in the slot profiles conventional milling and left like .050 around the whole profile, then climb milled in 2 cuts. .5" and 1.25" for a "finish pass".
I ended up having to hand fit the trigger and hammer. Took about .010" off each side to clearance them.

To update the thread:

I had a little problem with the safety having play. Made for a sloppy movement with minimal detent engagement. Most concerning was the lever wanting to go into select fire position with a little forward pressure...

Pulled the lower back apart and inspected closely...
Could not find any signs of a burr or other interference.
Checked the spring... seemed fine...

I figured it had to be the pocket depth in the grip...
Took a finishing brad and cut it off about 3/16" from the t-head and stuffed in the hole...
Checked fit...
Too dang tight...

Pulled grip back off... drove the brad into the plastic with a steel punch and a hammer.
Rechecked fit...
Perfect!

The other issue that bothered me was the trigger.
Did the set screw fix...
Fixed it up real nice.
Shaping up as a nice start to a precision rifle i can be proud of!

Lol.  I never trust much of any software for anything.  For 4 flute cutters in 7075, I like to rough in conventional direction at about 1,200 RPM and do final passes climbing, taking 0.002-0.005 at 2,700.  I also plunge .250" at a time doing lowers with a 7/16" cutter.  I use 1.5 or 2" LOC 4 flute HSS end mills for these, BTW.

They come out pretty clean at those S&F, dry cutting.  I do not use jigs, just square up, index and watch the DROs





And in 2219-T6 (my 1/2 scale):



There's no need for coolant on 7075-T6 if your speeds and feeds are reasonable.  I've never had flutes clog like that in 7075 or 2219, whether using HSS, uncoated Ti , TiN or TiAlN.

As for your tight trigger, I would say the issue is the radius at the front of your FCG pocket.  It appears you attacked this lower with a 7/16" cutter, but the front of the pocket is carrying a larger radius; large enough that the hammer pivot is in that radius.  Did you have a hard time driving pins?



The terms are not forward and backward; it's conventional and climb.  And at the RPMs he was running that cutter, I'd have to stare at the image longer than I care to to be certain which way it was running in what part.  CNC and CAM do like to climb mill more often than not, though.

I used a 3/8" 2fl hss and a 1/2" 2fl hss for the pockets and a 4fl carbide TiN coated em for the trigger slot.

I climb roughed - .100" passes and left about .050 on the profile for finish.

I sped up rpm a little and conventional milled to finish.


To update:

One can blow the better part of a paycheck in a right damn hurry building a rifle...

Got all my goodies ordered except the barrel.
Still pondering on that one.

Great photos. Thanks

Nice to see some real artisanship going into a build.

Anticipation is making me want to cut out from work early to go watch for delivery trucks.

Everything for this build is ordered...

Should get my anderson stripped forged upper in the white today.
And the nickel boron bcg...
Maybe the upper parts kit and buffer tube/butt stock assembly.

Still need to get a wrench tho lol.

Ended up going with a 16" 1:8 .223 wylde in 416 stainless off fleabay.
For 114$ shipped I wont feel too bad beating the total hell out of it.

I will decline to share the rest of the build list until after I get it completed and have some groups on paper.

Thanks Richard.
Wouldn't quite call myself an artisan at building these things just yet.
Definitely some room for improvement, but I appreciate the morale boost!

Looks good. How are you going to finish them? Home brew anodize?

the upper and lower will stay "in the white". Barrel is 416 stainless and will remain in its bright machined finish. Foregrip is black with knurling... I will be stuffing it in a lathe and cutting the tops off the knurls...

Standard black 6 pos buttstock. Black hardware... for now.

Some more parts are slowly trickling in...
Still waiting on buttstock, handguard, barrel, and gas tube.

Here is the updated volley of images...

And it's complete.

Looks good. You gonna paint it?

Thank you, and no. I'm going to turn some of the black back off the foregrip and call it done. Wanted a shiny one... all I ever see in Black Rofled... are Black Rifles lol.

Results from first test run are encouraging.
Call me chicken if you want lol...

http://s1282.photobucket.com/user/Christofer_Taylor/media/Mobile%20Uploads/2015-03/20150314_162507_zpsov25pnkx.mp4.html

Should have tightened them set screws a little more...

http://s1282.photobucket.com/user/Christofer_Taylor/media/Mobile%20Uploads/2015-03/20150314_165631_zpsbnsa6pm3.mp4.html


That's more like it...
http://s1282.photobucket.com/user/Christofer_Taylor/media/Mobile%20Uploads/2015-03/20150314_165949_zpsmbn97tpg.mp4.html


Some holes in some paper...
Distance was about 30 yards stepped off in swampy muck.

3rnds semi supported
http://i1282.photobucket.com/albums/a540/Christofer_Taylor/Mobile%20Uploads/2015-03/20150314_201233_zpscditxgyt.jpg

5rnds
http://i1282.photobucket.com/albums/a540/Christofer_Taylor/Mobile%20Uploads/2015-03/20150314_201147_zpseymcsnkc.jpg

3rnds
http://i1282.photobucket.com/albums/a540/Christofer_Taylor/Mobile%20Uploads/2015-03/20150314_201207_zpsji7isjvf.jpg

The 3 that look like flyers on the 3rd target were not exactly flyers...
I'm going to need a new fcg...
I lost sear engagement and am getting hammer drop when I relax trigger after squeezing one off... took me 3 occurrences to figure out why it was double tapping...


So far... even with the craptastic factory crown job on the muzzle,  I'm pretty confident this one will be a nice shooter.

Weighed it before I went to the range and it's 6lbs 2oz with no mag.

Did it triple fire when the gas block slid forward or was that just extra gas?

It was a fire on pull, fire on release and surprised me so I squoze  off another one after the gas block was loose... blowing it into camera view.