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AR 80% lower finishing - Order of operations?
- Thread starter ScrapMetal
- Start date
- Joined
- Sep 24, 2014
- Messages
- 926
I wish I could give pointers on the anodizing. I have yet to try out anodizing. The process appears to be straight forward. Calculating your surface area and setting voltage seem to be the critical elements along with temperature.
I plan to Ceracoat my first project. I picked up a starter set at Christmas.
- Joined
- Aug 24, 2013
- Messages
- 56
Mr. ScrapMetal,
Do not underestimate the value and use of jigs. How do you think Rosie the Riveter made such an impact in production during WWII? She did not edge find and locate the holes she drilled or milled in the millions of pieces of gear she produced. No, she used a jig. She had no clue of how to properly locate a hole. Did her items work? Absolutely. The layout man or foreman laid out all her work she just drilled the holes for the size drill she was given that day.
A properly made jig is a very valuable time saver in doing multiples work. If you are worried about accuracy incorporate hardened drill bushings into the plan. That way a ruined guide hole is quickly and cheaply replaced. I also do projects such as yours and find good quality jigs make things faster and more affordable all around. A hardened steel drill bushing will probably outwear the aluminum jig anyway.
Your KURT vice jaws are impressive. You seem to have the knack for doing clean work.
Do not underestimate the value and use of jigs. How do you think Rosie the Riveter made such an impact in production during WWII? She did not edge find and locate the holes she drilled or milled in the millions of pieces of gear she produced. No, she used a jig. She had no clue of how to properly locate a hole. Did her items work? Absolutely. The layout man or foreman laid out all her work she just drilled the holes for the size drill she was given that day.
A properly made jig is a very valuable time saver in doing multiples work. If you are worried about accuracy incorporate hardened drill bushings into the plan. That way a ruined guide hole is quickly and cheaply replaced. I also do projects such as yours and find good quality jigs make things faster and more affordable all around. A hardened steel drill bushing will probably outwear the aluminum jig anyway.
Your KURT vice jaws are impressive. You seem to have the knack for doing clean work.
- Joined
- Apr 6, 2011
- Messages
- 2,080
I did not intend to come across as being opposed to jigs in general as I use them all the time, they have their place. Depending on your equipment and what you are trying to accomplish though, they could be more of a hindrance than a help. In the case of jigs for AR lowers all the jigs I have seen have been built/designed for use with a drill press or at best a mill without DRO or accurate measuring tools and have also been constructed out of aluminum.
Now, if all you intend for is to make a single lower, are not too concerned with accuracy, and don't mind some less than optimal aesthetics one of these jigs could possibly get the job done. It would take a load of patience, attention to detail, and most likely a number of "Uhhg crap!
" moments but it can result in something usable.
Here are what I see as problems with these jigs:
First of all, when the 80% lower is completely enclosed within the jig there is no way to tell if the lower's orientation within the jig is correct, "square", etc. If it's not then everything done from that point on can be skewed.
Next, when you use the drilling guides you will never have the drill perfectly in line with the holes. Even if by some miracle it was there would still be run out on the drill bit, drill chuck, or drill press table that would cause it to be "off". Granted, some of these issues apply to the mill as well so we try and minimize them the best we can. As the jig is made from the same material you are cutting (or even softer), each time you use that hole it will become more oblong and less accurate. Drill bushings would be great for the side holes (trigger group pins, safety, etc.) but if the drill is not started in straight there would still be enough slop to make a difference.
This also applies to when you trying to mill out the fire control cavity. You will need multiply passes with an end mill and each time you hit the side of the jig you will be taking a chunk out of it. Since we are not using a DRO to tell us when to "stop" all we can go on is visual and audio clues, both of which will result in buggering up the jig "guide" a little bit more each time.
Then there are problems in just using the jig. The drill/route guides covering the top of the fire control cavity created a couple of issues in itself. The first of which is that any drill or end mill had to be an extra half inch long to reach the bottom of the cavity so instead of needing a drill/end mill with a cutting depth of 2.5" you will need one with 3" of depth, a costlier tool with less rigidity.
I also found that the jig made it more difficult to clear out the chips as the "guide" acted like a lid over the cavity and kept everything right there making it more difficult to see what the cutter was doing and making the cut less clean.
Another issue was when reconfiguring the jig as every time you take it apart to put in a different guide there was no guarantee that once it was re-assembled that it would be "zero" with itself or the lowers orientation within it would be the same.
I could keep going but I've gotten across the general experience I had with a jig in this case. I am sure that there are some AR lower jigs that would perform better than the one I had in hand but even then some of these issues will just not go away. In my opinion, if you have access to a mill with an accurate DRO and practice proper cutting, measuring, and mounting techniques you would be better off without trying to use one of the lower jigs on the market.
JMHO
Oh, and UncleRuss, thanks on the jaws. I try and do my best.
-Ron
Now, if all you intend for is to make a single lower, are not too concerned with accuracy, and don't mind some less than optimal aesthetics one of these jigs could possibly get the job done. It would take a load of patience, attention to detail, and most likely a number of "Uhhg crap!
" moments but it can result in something usable.Here are what I see as problems with these jigs:
First of all, when the 80% lower is completely enclosed within the jig there is no way to tell if the lower's orientation within the jig is correct, "square", etc. If it's not then everything done from that point on can be skewed.
Next, when you use the drilling guides you will never have the drill perfectly in line with the holes. Even if by some miracle it was there would still be run out on the drill bit, drill chuck, or drill press table that would cause it to be "off". Granted, some of these issues apply to the mill as well so we try and minimize them the best we can. As the jig is made from the same material you are cutting (or even softer), each time you use that hole it will become more oblong and less accurate. Drill bushings would be great for the side holes (trigger group pins, safety, etc.) but if the drill is not started in straight there would still be enough slop to make a difference.
This also applies to when you trying to mill out the fire control cavity. You will need multiply passes with an end mill and each time you hit the side of the jig you will be taking a chunk out of it. Since we are not using a DRO to tell us when to "stop" all we can go on is visual and audio clues, both of which will result in buggering up the jig "guide" a little bit more each time.
Then there are problems in just using the jig. The drill/route guides covering the top of the fire control cavity created a couple of issues in itself. The first of which is that any drill or end mill had to be an extra half inch long to reach the bottom of the cavity so instead of needing a drill/end mill with a cutting depth of 2.5" you will need one with 3" of depth, a costlier tool with less rigidity.
I also found that the jig made it more difficult to clear out the chips as the "guide" acted like a lid over the cavity and kept everything right there making it more difficult to see what the cutter was doing and making the cut less clean.
Another issue was when reconfiguring the jig as every time you take it apart to put in a different guide there was no guarantee that once it was re-assembled that it would be "zero" with itself or the lowers orientation within it would be the same.
I could keep going but I've gotten across the general experience I had with a jig in this case. I am sure that there are some AR lower jigs that would perform better than the one I had in hand but even then some of these issues will just not go away. In my opinion, if you have access to a mill with an accurate DRO and practice proper cutting, measuring, and mounting techniques you would be better off without trying to use one of the lower jigs on the market.
JMHO
Oh, and UncleRuss, thanks on the jaws. I try and do my best.
-Ron
- Joined
- Aug 24, 2013
- Messages
- 56
I can totally agree with every point you made. However, for the inexperienced it could scare the living devil out of them to the point that they would never even try to take on a project such as this. A gun is a rifle, a rifle is a gun. Point being that I am sure Eugene Stoner and his crew allowed for "slop" in their design efforts. Else every trigger pull would be the same in creep and let off. Exactly. Five million M1 Garands and six and a half million M1 Carbines attest to this point. The carbines for the most part being turned out in a bare two years of time. The manufacture of carbines also employed thousands of sub contractors, some even being Mom and Pop operations with a basement or garage machine shop. That is why most all carbine parts are marked as to maker so if there is failure or a problem they could track down who produced it.
Along these same general lines are the people think that a gun part is a piece of the holy grail. A screw is a screw and a pin is a pin, whether it came from Remington or the local hardware store. Some think that a screw replaced deletes from the value of the firearm. People bring me guns to work on all the time but I seldom work in front of them as they stare in fear of my methods. Although they are happy when they pick it up after my work.
Obviously you have the knowledge and ability to follow such exacting standards, I applaud you for your efforts. My point is with a little thought and desire a lot of "average" guys can complete a project such as this.
It sometimes amazes me how screwed up something can be and still function!
Along these same general lines are the people think that a gun part is a piece of the holy grail. A screw is a screw and a pin is a pin, whether it came from Remington or the local hardware store. Some think that a screw replaced deletes from the value of the firearm. People bring me guns to work on all the time but I seldom work in front of them as they stare in fear of my methods. Although they are happy when they pick it up after my work.
Obviously you have the knowledge and ability to follow such exacting standards, I applaud you for your efforts. My point is with a little thought and desire a lot of "average" guys can complete a project such as this.
It sometimes amazes me how screwed up something can be and still function!
- Joined
- Apr 6, 2011
- Messages
- 2,080
I agree completely!
(Except for maybe the part about my knowledge and ability. 
)-Ron
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