80% Machining fail

[RazzB7]

I was hoping to post a picture of one of my newly machined FCP on here today. I have always thought it is just as important to post our failures as well as our successes on a forum like this, so everyone can learn. So, I swallow my pride and present my folly to you!

I've read on here how people have done these with a drill press and I've read on here how people have screwed them up with a drill press. Today you can count me in the second group. I'm bummed. It looks like it is FUBAR. The thin section right by the bolt release is my biggest concern.



I have a big old heavy industrial drill press and an X-Y table. So, I chucked up the 7/16 end mill and went to town. I was doing well and going slow. Feeling pretty proud of myself.

Then it happened, I got the dreaded "death wobble" and before I could shut it down I had screwed up my receiver.

So, I will be saving my pennies for a mill. I've been wanting one for a while anyway and I have other uses for one.

Colfax will be happy with me, they'll sell another 80% lower. At least someone's happy.

[goldfinger]

That will still work. Well, I've f'd two of mine in that area, both has holes through the mag latch, but still works. And I'm using a mill.

[incredablehefey]

That will still work.

i agree, finish milling it and put it together! you will never be able to tell once it is put together, plus there is no doubt that you made that receiver from an 80%

[Mud]

Did you try Hogging out the majority of metal with Drill Bits, then attack with end mills? I agree, still looks salvageable. If it makes you feel any better, I have 4-5 blocks of Aluminum that went south on CNC and now just taunts/laughs at me from the scrap heap

[chillypepper]

I agree it's salvageable. and agree with Mud, drill most it out with drill bits first. then finish it out with the drill press.

[savs2k]

its still ok. ugly but itll work still after you clean it up. Just try not to mill it too far up anymore but the sides shouldnt harm too much how it is

[armygunsmith]

It's at least salvageable. It will only do for a pistol lower.

[rob474]

check this out mill group buy might help you finsh your 80%

http://www.calguns.net/calgunforum/showthread.php?t=520563

[Jason_2111]

As long as you maintain tight geometry between the trigger pin hole, hammer pin hole, selector lever hole, and forward and rear takedown pin holes, there's a lot in the lower that can be forgiven if it gets screwed up.
It's the one part that really doesn't see as much stress as you'd think.

Don't chuck it. Put it to the side and do another one... and then later, you might decide to come back to that one and finish it off and have it as a "spare".

[five.five-six]

yup, will still worrk

[sharxbyte]

If you're REALY concerned, find someone with an argon tank and a welder, put a bead on it, and re mill. but like they said, it should work.


Also, a good idea not to dry fire it.

[Intimid8tor]

I'm not an expert, but I think it will be ok. Just go to the correct dimensions on the rest of the milling.

The first one I do will be on tactical machining lower then comes the quentin and finally the yellow logic.

[VytamenC Tactical]

thats not messed up lol. you need to plung with a drill bit(depth of 1.20") first then switch to an end mill to clean it all up and finish to a depth of 1.25 . remember all this section does is hold your fire control group. THATS IT

[kcstott]

One it not fubared. You stopped in time to save it.
Two: the next time hog it out with a drill then go like .030" to .050" depthe of cut. Drill presses are not designed to take a side load so they react very badly to deep depth of cut. keep your cutter shallow and it will be easy.

[E-120]

Im not an expert, but there is very little force on the lower receiver. Specially in that area. I see no problem with it. I have machined 3 FWIW.