These are some perhaps obvious things to do when using the 5D Jig (and its clones). Just some things I learned while doing 2 lowers so far using this jig, router, and a drill press. And yes, this does mean I did the opposite of each of these on one lower or another.

1. Grip the router at the base plate. Gripping any higher will put slight torque on it at the pivot point (think of it toppling over) and eat into the walls of the lower as the endmill is at an angle. For me this caused the ramp where the walls thicken (just in front of the selector) to be uneven and actually split into two distinct ramps.

2. Make absolutely sure that the endmill is centered in the pilot-hole and won't grab the walls of the lower as it spins up - this will kick it around in your hands and it'll bite into some part of the fire control pocket. What I did was take extra time centering it, and when necessary I would widen the pilot hole with the drill press (on the surface, and not when at the bottom of the pocket).

3. Do slow methodical finishing passes on the walls

4. Make sure the jig is level horizontal when doing the side drilling. Depending on your vise you may need a wood block or some machinist's parallels at the bottom of your vise. Also watch out for jaw lift on the vise. As always, make sure the drill press clears the jig bushings by pressing it in and seeing if it returns on its own (while not under power). Binding in the bushing is bad news.

Even with this my lowers aren't CNC perfect but I think the remaining flaws are due to the jig. The left wall on my latest lower is thinner than the right wall.
Feel free to leave any more tips you have which aren't obvious to a newbie or not included in the manual, for mine and everyone's sake.

I use a foot pedal power switch to turn my router on and off. That lets me keep two hands on the router all the time that it's running.

I bought cheaper endmills instead of paying extra for the 5D endmills. They work ok and I don't feel bad if I chip one.

My next lower I'll be experimenting with a radius on my endmill.

How do you drill the LRBHO roll pin hole?

Which company makes a lower without that hole being drilled? That's fubar. I'll avoid them like the plague!!!

#2 my solution  for this is to go to a larger drill bit and drill the entire hole save the last 3/16”or so. I accomplish this by measuring the receiver depth, then marking the drill bit with paint or tape so you know when to stop. You could also use a stop on a drill press. This way there is less chance of the mill grabbing in start up.( and yes, I did  it on my very first one

I had heard it was Anderson.

Smart, I was just using the same drill bit and letting it run after offsetting slightly from the hole. You can't do more than a millimeter like this because the bit deflects and wants to go down the pilot hole. Plus you'd have to do this often which is more setup time.


I see, makes sense. I also still have some roughness/divots where the ramp occurs and the wall thickens, which are my main gripe about the jig.

I am looking forward to [color=#ff0000]this. Thanks!! [/color]

NoDak Spud does.


Edit --  No, my mistake.  The hole they don't drill that most do is the one for the selector detent.

are you sure it's not tapped?  threaded?  I presume you're talking about the bolt catch roll pin only having a through-hole on one side.

I had heard here, some time ago, that Anderson sent their 80% sample to BATFE Tech Branch w/o the LRBHO roll pin holes drilled, and thus, they sold their 80% lowers, w/ ATF approval letters, w/o the LRBHO roll pin holes drilled.  This is old information & may have changed.

Perhaps I was misinformed, or it was a long time ago.  I've had more than 40 Sabre Cav Arms Mk 2s pass through my hands, mostly as gifts, and have never had to drill the LRBHO roll pin holes.

I think I saw a couple of posts about bolt catch holes not drilled on lowers but that was on a companys finished lower not an 80%. Never seen anyone complain about an 80% with undrilled bolt catch holes.

The Nodak 80 % lower I bought did not have the selector detent hole completed but that was clearly stated on their web site it was not done and actually the selector detent hole is supposed to be located off the selector location so it only makes sense that if you want a straight selector lever it would not be done until after the selector hole is located within the prints allowances.

just as an aside, not sure why you're referring to the bolt-catch roll-pin hole as the "LRBHO" (last-round-bolt-hold-open) roll-pin hole.  although everybody here understood which hole you're referring to.

checking for LRBHO is something you do when evaluating whether you got the right buffer weight, buffer spring, or gas from the gas port.

The CNCGuns jig would do a bolt catch hole. Not sure it they still sell them and never seen a new style 80% that needed it done.

I have one of those jigs from back in the day when the original style 80% lowers were out.  Their web site is still up, but I have no idea if they are actually still in business or if they are still making jigs or still have those old style ones.

https://www.cncguns.com/tooling.html

Between modern jigs and the old CNC jig and all the extra taps and drill bits it required I could actually do about a 40 or 50% lower if I had to.  I'd still have to get a real milling machine to do 0% though.

If Biden forces us to forgings there will be router forging jigs in about 87 days.

Hell, I'd buy one right now if they were available.  If they ban forgings then worst case I have most of what I'd need to do castings of 0% blanks.  That would be hard to stop but yeah I know, not as good as a forging, but I could make as many as I wanted for relatively cheap.

What are they going to do then...  ban buying scrap aluminum?  Will they require every billet of aluminum to be registered and serial numbered and require a license and background check to buy?  Are they going to require a license to buy a milling machine?  A trim router?  Mill bits?  Jigs?  How can they do that given our current legal code?  How would they enforce it?

Decking the top of the upper, truing up the rear part of the buffer tube area and broaching the magazine well are the big things I can't easily do with what I have.  Many of the other milling operations I could make router jigs myself to do pretty easily.  If I have to I will find a way to buy a mill.

I do think you are right that Biden and his disgusting sycophants at BATFE may find that they will create a monster if they aren't careful.  What happens when you cut off the head of a snake and it just sprouts dozens more heads?

Many people will go out of their way just to prove the Stalinist regime is wrong and do it just out of spite.

F Biden up his bung hole with a rusty spike.  He's an A-hole and just a puppet for the socialist bastards that pull his strings.

Look up the Ray-Vin method for the magwell.  Broaches are not needed.

Well...  Nice.  That guide plus forgings or even castings lays it out pretty much so anyone with a milling machine can create lowers.

It would be super awesome to see something like this for doing a lower from a billet. I'd like to see Biden try to regulate billets.

Let's see them try to regulate Coke cans - and Legos.  

Exactly.  I have most of what I need to cast 0% lower blanks or make billets.  I even have a pretty good source of better than soda can aluminum for more or less free.