View Full Version : worn anodizing in pivot pin hole on brand new Daniel Defense upper
Androctonus
04-12-19, 21:33
Hi guys. I just got a DDM4 V7 upper. On inspection, it all looks near perfect besides the pivot pin and takedown pin holes. Each of those has the anodizing already worn through in spots. The pivot pin hole is worse. I tried to get a good picture. The anodizing is patchy and it looks like the aluminum in the hole is maybe a little marred too. It's got a very rough look to it.
The upper's been attached/detached from a few of my lowers maybe a dozen times. Funny thing, the upper locks up near perfectly with my lowers. Not too tight, but no wiggle. Think I should contact Daniel Defense about this? Or is this just chipped finish? I don't really care about the latter.
I would be absolutely amazed if attaching/detaching the upper a dozen (or several dozen) times would cause the amount wear in the anodizing shown in your photo.
What did they look like before you began attaching and detaching the upper?
My guess is that after the anodizing was applied, DD performed some additional QC testing and determined that some remediation was needed in those areas, and
removed a bit of material (and anodizing). If this is the case, then it's a good thing, since they seem to be dimensionally correct. This wouldn't be the first time, and
certainly not the last, that a dimension was modified after the anodizing step.
Androctonus
04-12-19, 22:40
Unfortunately, I didn't look at the pin holes before attaching the upper to a lower. I was too excited. But, I agree that the attaching/detaching I did probably wouldn't have caused the wear, even without applying lube first. My other two uppers don't look near like that after much more use.
I wondered if DD did some work on the holes. It doesn't really look like incomplete anodizing. I'm just concerned about the pin holes wearing out faster in the future due to the removed anodizing. But, the aluminum there should still be hardened from the anodizing?
Androctonus
04-15-19, 21:32
Thanks guys. I talked with DD and they said they do indeed hone pivot pin holes for a good fit.
Thanks guys. I talked with DD and they said they do indeed hone pivot pin holes for a good fit.Thanks for updating. You bought a great rifle.
Thanks guys. I talked with DD and they said they do indeed hone pivot pin holes for a good fit.
FPNI. They're feeding you a line. More than likely they found a dimensional issue during assembly where the pins wouldn't fit and the holes were reworked and never re-anodized. The lack of anodizing isn't likely to affect the fit, form or function of the gun itself but they sent it out anyway.
Androctonus
04-16-19, 19:44
FPNI. They're feeding you a line. More than likely they found a dimensional issue during assembly where the pins wouldn't fit and the holes were reworked and never re-anodized. The lack of anodizing isn't likely to affect the fit, form or function of the gun itself but they sent it out anyway.
Yeah, maybe they fed me a line. I was a little surprised to find such a thing on a DD upper, but, as long as it is a non-issue, I'm good with it. Worse things could've happened. The gas block is straight, the rifling looks good, no gas port burrs, the bcg and barrel extension look great. I never assume I'm getting a perfect rifle or upper just because I spent big bucks. I've had function issues straight out of the box, from a well respected manufacturer after they did function testing. They took care of it though.
SouthwestAviator
04-17-19, 16:07
I’ve had the same thing on my upper and lower pin holes. Daniel Defense told me it does not effect function at all. Does anyone know if it can affect overall lifespan of the lower, though?
MorphCross
04-17-19, 16:51
I’ve had the same thing on my upper and lower pin holes. Daniel Defense told me it does not effect function at all. Does anyone know if it can affect overall lifespan of the lower, though?
With regards to the pivot pin area, the lower will outlive multiple barrels, bolts, and springs.
SouthwestAviator
04-18-19, 13:43
Is finish wear in the pivot pin areas normal?
Is finish wear in the pivot pin areas normal?Kinda. Wear is normal in all areas where parts are moving against each other and creating friction. I imagine the less you take your rifle apart, the less wear you'll see in the pivot pin areas.
I’ve seen a bunch of uppers over the last year at least with DD doing this.
Androctonus
04-18-19, 22:14
If this isn’t an uncommon thing for DD to do, I guess it can’t really be bad. DD knows ARs well. But, pivot and takedown pin holes seem like a bad area to be without anodizing to harden the surface against the pins. I separate uppers and lowers frequently and it feels like there is friction in there, even with grease.
If this isn’t an uncommon thing for DD to do, I guess it can’t really be bad. DD knows ARs well. But, pivot and takedown pin holes seem like a bad area to be without anodizing to harden the surface against the pins. I separate uppers and lowers frequently and it feels like there is friction in there, even with grease.Maybe not bad, but not good either. At the very least indicative of a broken process. There's no good reason that these receivers shouldn't have been re finished.
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Androctonus
04-18-19, 23:26
Maybe not bad, but not good either. At the very least indicative of a broken process. There's no good reason that these receivers shouldn't have been re finished.
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The only reason I can think of is that re-anodizing would, as far as I know, slightly decrease the diameter of the pivot pin hole and potentially lead to fitting problems again. But, maybe that could be accounted for in the amount of removed material before re-anodizing. I’m tempted to ask them to switch over the parts to a new receiver, but I don’t want to argue with them about it.
Maybe not bad, but not good either. At the very least indicative of a broken process. There's no good reason that these receivers shouldn't have been re finished.
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They'd have to ream slightly larger than re-finish. Then hope it's the right size. Type III anodizing can be as thick as .003". Doesn't sound like much, but can make a pin hard to get in. Frankly, I don't see a single issue with them reaming to size.
They'd have to ream slightly larger than re-finish. Then hope it's the right size. Type III anodizing can be as thick as .003". Doesn't sound like much, but can make a pin hard to get in. Frankly, I don't see a single issue with them reaming to size.That's a call they're supposed to make through nonconformance reporting and quality/engineering disposition. If they can't meet the requirements (all of them, material, dimensional & anodizing) through rework, the parts get scrapped, or regraded (blem). They basically shipped non-conforming (blem) receivers and sold them as 1st quality, only question is whether they did it knowingly because someone would have to sign off on the decision to do it under any standard quality system.
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SouthwestAviator
04-19-19, 07:18
That's a call they're supposed to make through nonconformance reporting and quality/engineering disposition. If they can't meet the requirements (all of them, material, dimensional & anodizing) through rework, the parts get scrapped, or regraded (blem). They basically shipped non-conforming (blem) receivers and sold them as 1st quality, only question is whether they did it knowingly because someone would have to sign off on the decision to do it under any standard quality system.
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Couldn't it just be that everything was done right at the factory, but it's so tight that firing it causes the finish wear in the pin holes (there is almost no play between the upper and lower on mine)? I was told it was normal. My only concern is whether it will cause the receiver to have less service life. It’s present in the lower on mine.
ETA: I never noticed the finish wear in my pin holes until after I had about 1000 rounds through it. Not sure if I just hadn’t noticed it before then or if it was part of the break in.
Androctonus
04-19-19, 07:37
Couldn't it just be that everything was done right at the factory, but it's so tight that firing it causes the finish wear in the pin holes (there is almost no play between the upper and lower on mine)? I was told it was normal. My only concern is whether it will cause the receiver to have less service life. It’s present in the lower on mine.
That seems unlikely. Potentially sacrificing receiver service life for an extra tight fit doesn’t seem like something DD would do. Tight fit is nice, but isn’t all that important.
SouthwestAviator
04-19-19, 07:43
That seems unlikely. Sacrificing receiver service life for an extra tight fit doesn’t seem like something DD would do. Tight fit is nice, but isn’t really important.
Are you saying that the finish wear is unlikely to affect service life?
Androctonus
04-19-19, 07:51
Are you saying that the finish wear is unlikely to affect service life?
No. I’m concerned about finish wear affecting service life. My upper may fit tight now, but wondering if the lack of finish will lead to a looser fit later. Maybe it will, maybe it won’t.
Seems unlikely that leaving pin holes without anodizing would be standard operating procedure for them. Don’t think they do that to have a tight fit, but with a reduced service life.
Couldn't it just be that everything was done right at the factory, but it's so tight that firing it causes the finish wear in the pin holes (there is almost no play between the upper and lower on mine)? I was told it was normal. My only concern is whether it will cause the receiver to have less service life. It’s present in the lower on mine.From those pics, not likely. I'd imagine there's a whole batch of receivers just like it that they sent out.
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Androctonus
04-19-19, 08:01
From those pics, not likely. I'd imagine there's a whole batch of receivers just like it that they sent out.
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Yeah, that’s probably true.
No. I’m concerned about finish wear affecting service life. My upper may fit tight now, but wondering if the lack of finish will lead to a looser fit later. Maybe it will, maybe it won’t.
Seems unlikely that leaving pin holes without anodizing would be standard operating procedure for them. Don’t think they do that to have a tight fit, but with a reduced service life.Theoretically it could reduce service life, the holes are now bare aluminum now with no hardened anodized layer. In actual practice, how often are you swapping uppers?
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SouthwestAviator
04-19-19, 08:26
Theoretically it could reduce service life, the holes are now bare aluminum now with no hardened anodized layer. In actual practice, how often are you swapping uppers?
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It’s not the swapping uppers I’m worried about. It’s once I get to high round counts. This sucks to even have to worry about with a $1600 rifle.
My wear looks a little different from the OP’s. It looks more like it was from firing as it’s in the direction of the the recoil and is spotty. Will post pics shortly. DD customer service assured me it was normal break in with the steel pins in an aluminum receiver.
Androctonus
04-19-19, 08:36
On average, I separate uppers and lowers once or twice a week if I had to put a number on it.
This is ARFCOM levels of goofball. There is nothing at all wrong with that upper.
It’s not the swapping uppers I’m worried about. It’s once I get to high round counts. This sucks to even have to worry about with a $1600 rifle.
My wear looks a little different from the OP’s. It looks more like it was from firing as it’s in the direction of the the recoil and is spotty. Will post pics shortly. DD customer service assured me it was normal break in with the steel pins in an aluminum receiver.Pics?
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This is ARFCOM levels of goofball. There is nothing at all wrong with that upper.Speaking as a quality manager, your statement is not correct.
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SouthwestAviator
04-19-19, 09:43
https://imgur.com/a/HE4wmah
Thoughts? There’s some crap on one that someone else thought was a crack but it’s just fuzz from cleaning. The only imperfection is the obviously worn spots.
It’s not the swapping uppers I’m worried about. It’s once I get to high round counts. This sucks to even have to worry about with a $1600 rifle.
My wear looks a little different from the OP’s. It looks more like it was from firing as it’s in the direction of the the recoil and is spotty. Will post pics shortly. DD customer service assured me it was normal break in with the steel pins in an aluminum receiver.
We already established, and you've admitted, that you worry way too much about what happens "at high round count" in other threads... By the time you've worn this rifle out you won't even care anymore. Just go shoot the damn thing.
On average, I separate uppers and lowers once or twice a week if I had to put a number on it.Why?
And if I'm coming across as snarky, well you've read me right. I'm normally one of the least confrontation members, but this shit is starting to push me over the edge.
https://imgur.com/a/HE4wmah
Thoughts? There’s some crap on one that someone else thought was a crack but it’s just fuzz from cleaning. The only imperfection is the obviously worn spots.Pictures are crap, looks like material has been displaced at the front pin hole?
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And if I'm coming across as snarky, well you've read me right. I'm normally one of the least confrontation members, but this shit is starting to push me over the edge.
Take a step back....https://www.youtube.com/watch?v=yooamJf-T_8
That's a call they're supposed to make through nonconformance reporting and quality/engineering disposition. If they can't meet the requirements (all of them, material, dimensional & anodizing) through rework, the parts get scrapped, or regraded (blem). They basically shipped non-conforming (blem) receivers and sold them as 1st quality, only question is whether they did it knowingly because someone would have to sign off on the decision to do it under any standard quality system.
It would seem to me that if DD is following their normal process by hand fitting the take down pins, they are following their processes. From what the Sid Sleuths have found on internet searches, it is apparent that this is a 'trademark' (if you would) of Daniel Defense.
This is what the OP said: Funny thing, the upper locks up near perfectly with my lowers. Not too tight, but no wiggle. Think I should contact Daniel Defense about this? Or is this just chipped finish? I don't really care about the latter.
Later post: I talked with DD and they said they do indeed hone pivot pin holes for a good fit.
Seems the process works. Probably meets some ISO 9001 bullshit to boot.
thegreyman
04-19-19, 18:27
Think about this:
http://www.irvingberlin.com/god-bless-america
or this:
https://www.youtube.com/watch?v=RqnfndXHuXk
This is ARFCOM levels of goofball. There is nothing at all wrong with that upper.
Truth.... this place is forked.
Take a step back....https://www.youtube.com/watch?v=yooamJf-T_8
Thanks. I loved that movie.
I stepped away. Went to my property and fired a few Failure to Stop drills with my G19 and went back to working on my roof. :D All is o.k. in my world.
Androctonus
04-19-19, 23:47
https://imgur.com/a/HE4wmah
Thoughts? There’s some crap on one that someone else thought was a crack but it’s just fuzz from cleaning. The only imperfection is the obviously worn spots.
The pic looks a bit fuzzy, but the inside of your lower's pivot pin hole looks similar to the one in my upper.
It would seem to me that if DD is following their normal process by hand fitting the take down pins, they are following their processes. From what the Sid Sleuths have found on internet searches, it is apparent that this is a 'trademark' (if you would) of Daniel Defense.
This is what the OP said: Funny thing, the upper locks up near perfectly with my lowers. Not too tight, but no wiggle. Think I should contact Daniel Defense about this? Or is this just chipped finish? I don't really care about the latter.
Later post: I talked with DD and they said they do indeed hone pivot pin holes for a good fit.
Seems the process works. Probably meets some ISO 9001 bullshit to boot.
Yes, it seems apparent that this is a "trademark" of DD receivers. Good enough for me. Time to go shoot the rifle and enjoy the nice new upper. Thanks for the helpful replies and apologies to those who thought all this was a bit silly. I get a bit OCD about my rifles sometimes, but I do put them to good use.
Yes, it seems apparent that this is a "trademark" of DD receivers. Good enough for me. Time to go shoot the rifle and enjoy the nice new upper. Thanks for the helpful replies and apologies to those who thought all this was a bit silly. I get a bit OCD about my rifles sometimes, but I do put them to good use.
There's usually no need for apologies here for different opinions. I'm the first one to beat up DD on their old horrible gas port sizes... But this is a total non issue in my opinion.
And someone suggested that DD was giving you a line of bull. I'd challenge them to answer the phones and field the barrage of insane inquiries these poor folks must get every day.
Uncoated 7075 Al will form an oxide layer that is plenty hard enough to handle pins being pushed out by hand. The idea that the lack of anodizing in the pin holes will cause wear is silly.
Could someone please find and exhibit ONE example of receiver pin holes “wearing out,” either from separation of upper and lower or from “firing high round counts?” I’ve never seen one, but I’m always willing to learn.
Androctonus
04-20-19, 18:21
There's usually no need for apologies here for different opinions. I'm the first one to beat up DD on their old horrible gas port sizes... But this is a total non issue in my opinion.
And someone suggested that DD was giving you a line of bull. I'd challenge them to answer the phones and field the barrage of insane inquiries these poor folks must get every day.
Thanks. Seriously, I've wondered what it's like to run CS for a company like DD. It probably gets rough sometimes. I've heard people complain about DD's being over-gassed, but, one could use a heavier buffer.
Could someone please find and exhibit ONE example of receiver pin holes “wearing out,” either from separation of upper and lower or from “firing high round counts?” I’ve never seen one, but I’m always willing to learn.
I searched and couldn't really find anything. I've read about military M-16s being sloppy as hell in the upper lower fit from use, but who knows what abuse those get over the years. Even then, it seems the rifles still do their jobs quite well.
Are DD receivers anodized or powder coated?
Are DD receivers anodized or powder coated?
They are type III anodized. Some of their receivers get a cerakote job on top of that.
This is ARFCOM levels of goofball. There is nothing at all wrong with that upper.
THEN: Pointy elbows, would not bang.
NOW: Fitting marks, would not buy.
It would seem to me that if DD is following their normal process by hand fitting the take down pins, they are following their processes. From what the Sid Sleuths have found on internet searches, it is apparent that this is a 'trademark' (if you would) of Daniel Defense.
This is what the OP said: Funny thing, the upper locks up near perfectly with my lowers. Not too tight, but no wiggle. Think I should contact Daniel Defense about this? Or is this just chipped finish? I don't really care about the latter.
Later post: I talked with DD and they said they do indeed hone pivot pin holes for a good fit.
Seems the process works. Probably meets some ISO 9001 bullshit to boot.
Hand fitted take down pins? :lol: I almost spit out my coffee! Now that's some epic ARFCOM level of silliness, despite what the customer service guy says. I'm sure he's keyed into what's happening on the machine shop floor though honing isn't even the proper operation to use... :rolleyes:
My issue here isn't that pin holes are going to wear out, I suppose that it's theoretically possible but not likely. My issue is that those receivers are basically rejects that were half-ass reworked and sold off as 1st quality at a premium. We as consumers shouldn't accept this just like you shouldn't accept unstaked carrier keys, and rifle barrel extensions with M4 receivers.
Hand fitted take down pins? :lol: I almost spit out my coffee! Now that's some epic ARFCOM level of silliness, despite what the customer service guy says. I'm sure he's keyed into what's happening on the machine shop floor though honing isn't even the proper operation to use... :rolleyes:
I don't know how DD does it.
The OP said DD told him they honed them, to ensure proper fit, I guess that might be classified as hand fitting.
CajunCourier
04-22-19, 13:48
I was also told that it was due to honing the fit, presumably in order to be snug with little or no wobble between receivers.
SouthwestAviator
04-22-19, 14:34
I spoke with someone at DD who was very helpful. What he explained lines up with what others have said: they hone the pin holes which can lead to some of the color coming off, but the anodizing process still changes the surface structure of the metal even if the color has come off.
I'm not sure I'd put color wear in pivot pin holes in the same category of unstaked gas keys and lack of M4 feedramps. Those two things affect reliable function and durability, and it sounds like the pivot pin hole thing doesn't.
Androctonus
04-22-19, 15:33
I spoke with someone at DD who was very helpful. What he explained lines up with what others have said: they hone the pin holes which can lead to some of the color coming off, but the anodizing process still changes the surface structure of the metal even if the color has come off.
I'm not sure I'd put color wear in pivot pin holes in the same category of unstaked gas keys and lack of M4 feedramps. Those two things affect reliable function and durability, and it sounds like the pivot pin hole thing doesn't.
Thanks for the update. I got a the same answer when I called DD. They assured me that no accelerated wear of the pin holes would occur. They're a good company, so there's no reason not to trust them. Every manufacturer is going to do things a little bit differently.
Yeah, shiny aluminum in pivot pin holes is not even in the same league as unstaked gas keys and incorrect feed ramps.
DD is free to do and tell you guys whatever they want. This "process" sounds fishy AF from a manufacturing standpoint (applying a surface conversion treatment or coating, then performing further machining operations that remove it) and I can't figure why on God's green Earth anyone would spend valuable machine time further working takedown pin holes after machining that's not part of a rework. To what end? Is there a surface finish requirement? Can't we hold this tolerance during the initial operations?
Like really, it makes no sense to me. But whatever, I got my own shops to run. I'll bow out.
Androctonus
04-22-19, 16:37
DD is free to do and tell you guys whatever they want. This "process" sounds fishy AF from a manufacturing standpoint (applying a surface conversion treatment or coating, then performing further machining operations that remove it) and I can't figure why on God's green Earth anyone would spend valuable machine time further working takedown pin holes after machining that's not part of a rework. To what end? Is there a surface finish requirement? Can't we hold this tolerance during the initial operations?
Like really, it makes no sense to me. But whatever, I got my own shops to run. I'll bow out.
I get your point. It's weird and I'd rather have anodized pin holes, but it's a nice upper and I'm going to enjoy it. I'm sure the whole thing started because a lot of people get bent out of shape about upper/lower fit, which, as far as I know, is a non-issue. I once had an accu-wedge in one of my rifles and quickly tired of it.
I looked at a friend's DD rifle. I see the same thing that OP noticed, but it was done to the lower, and not the upper.
It doesn't affect the function of the rifle, but I can understand if it bothers someone.
Androctonus
04-22-19, 18:45
Yeah, DD "hones" the holes in both their uppers and lowers.
I guess if I wanted to have receivers that fir snugly together with no wobble, I'd spec the holes at the bottom end of the spec - tight. Then I'd go ahead and put them in a jig, get some deadnuts-to-mid-spec pins and ream to that spec.
As SryOfcr mentioned, I don't think 'honing' is the best way to do that. Either process would remove surface finish.
Give me a break, likely they’re performing a perfectly legitimate operation on parts that are slightly out of tolerance after anodizing. Anodizing can add up to .003 to dimensions. That’s huge especially on a hole, and even more potentially problematic with hole size AND location tolerance stacking on mating parts. Hell, a couple tenths will make you have to use a punch to get your pins out. These aren’t space shuttle parts.
What they probably do is have assemblers put any receiver that doesn’t go tegther easily by hand in a bin and rework them later.
Androctonus
04-22-19, 19:40
I guess if I wanted to have receivers that fir snugly together with no wobble, I'd spec the holes at the bottom end of the spec - tight. Then I'd go ahead and put them in a jig, get some deadnuts-to-mid-spec pins and ream to that spec.
As SryOfcr mentioned, I don't think 'honing' is the best way to do that. Either process would remove surface finish.
Ah, I don't claim to know much about machining processes. I was just using the word I got from DD.
Honing is just abrasive machining, usually in reference to making holes round and the proper size.
I've thought about this overnight. Wouldn't this "honing" step make it into a factory second, or b grade product? How was the upper advertised?
Androctonus
04-23-19, 11:33
I've thought about this overnight. Wouldn't this "honing" step make into a factory second, or b grade product? How was the upper advertised?
I too have thought of this. The upper wasn’t advertised as a blem and it seems others have had the same experience. I’m sure manufacturers differ as to what is considered blem. The honing is apparently SOP for DD. I don’t have anything against blems anyway. Good way to save some dough, but I already did that with this upper.
Doc Safari
04-23-19, 11:35
I've thought about this overnight. Wouldn't this "honing" step make into a factory second, or b grade product? How was the upper advertised?
Just in general I would say ANY hand-fitting on an AR part goes against mil-spec and would certainly not be part of the TDP. My suspicion is that DD thinks it's a smart marketing move to order receivers with pivot holes that are undersized by a few thousandths. That way they can do some hand-fitting to make the customer think they're getting a precision-matched receiver set or something. That's my speculation only.
I've thought about this overnight. Wouldn't this "honing" step make into a factory second, or b grade product? How was the upper advertised?
I looked at an advertisement and didn't see anywhere they claimed each hole was anodized.
In terms of a second rate product, pretty sure most custom shops do some honing and handfitting of parts.
I'm just a hobby assembler, but if you get a rifle from me it will have the anodizing at the front of the receiver gone because I lap that portion of the receiver to square it as much as possible before installing the barrel. Does this help? I'm sure some, IDK how much, but I enjoy the process.
Don't agree with the second rate product mindset. Would folks be happier if DD daubed some aluma-black in there after honing?
Yeah, DD "hones" the holes in both their uppers and lowers.
I looked at a friend's DD rifle. I see the same thing that OP noticed, but it was done to the lower, and not the upper.
It does not appear that this is a repeatable manufacturing process. If it were, either every upper, every lower or both would be "honed" without exception. Seems more likely that...
What they probably do is have assemblers put any receiver that doesn’t go togther easily by hand in a bin and rework them later.
Which would be standard manufacturing process for handling non-conforming material for an shop that has any type of industry standard quality management system. Whether API, ISO, AS9100, TS16949, ect. But then again, someone should be questioning why the hell these parts are making out of the machine, over to ano then to assembly before we caught a dimensional issue?
8.7 Control of nonconforming outputs
8.7.1 The organization shall ensure that outputs that do not conform to their requirements are
identified and controlled to prevent their unintended use or delivery.
The organization shall take appropriate action based on the nature of the nonconformity and its effect
on the conformity of products and services. This shall also apply to nonconforming products and
services detected after delivery of products, during or after the provision of services.
The organization shall deal with nonconforming outputs in one or more of the following ways:
a) correction;
b) segregation, containment, return or suspension of provision of products and services;
c) informing the customer;
d) obtaining authorization for acceptance under concession.
Conformity to the requirements shall be verified when nonconforming outputs are corrected.
8.7.2 The organization shall retain documented information that:
a) describes the nonconformity;
b) describes the actions taken;
c) describes any concessions obtained;
d) identifies the authority deciding the action in respect of the nonconformity.
I looked at an advertisement and didn't see anywhere they claimed each hole was anodized.
In terms of a second rate product, pretty sure most custom shops do some honing and handfitting of parts.
I'm just a hobby assembler, but if you get a rifle from me it will have the anodizing at the front of the receiver gone because I lap that portion of the receiver to square it as much as possible before installing the barrel. Does this help? I'm sure some, IDK how much, but I enjoy the process.
Don't agree with the second rate product mindset. Would folks be happier if DD daubed some aluma-black in there after honing?
And I don't see anywhere that they're claiming hand fit take down pin holes... Seems like they'd want to advertise that feature to Mr. Fudd. But they are advertising Type III Hard Coat Anodizing and I didn't see an asterisk *except for pin holes.
LOWER RECEIVER: Mil-Spec with Enhanced Flared Magazine Well and Rear Receiver QD Swivel Attachment Point. CNC Machined of 7075-T6 Aluminum, Type III Hard Coat Anodized
UPPER RECEIVER: Mil-Spec with Indexing Marks and M4 Feed Ramps. CNC Machined of 7075-T6 Aluminum, Type III Hard Coat Anodized
In my world, anything that needs to be handfit on a modular platform is nonconforming. This isn't the turn of the [20th] century, CNC machining is capable of turning out incredible, repeatable precision and you can model fit and function in SOLIDWORKS. If they wanted a tighter tolerance on the pin holes, all they have to do is program it. I'm coming from a Crosby quality school of thought where the definition of quality is conformance to requirements. Which means that it's not 1st quality unless it meets all applicable material specs, dimensional specs, coating specs, assembly specs, inspection/test specs and has all of the documentation to prove it. So no, dabbing some Aluma-Black on the holes wouldn't make me happy. What would make me happy is if they sold these clearly as 2nd quality (like BCM), or reworked them back to 100% in-spec where no one would be the wiser. After all, would we be having this conversation if there wasn't clear evidence that something "wasn't right" regardless of DD's cover story?
EDIT: I called DD, and their shop does not have a certified quality system, which is not necessarily a horrible thing. I'd just have to jump through extra hoops to validate them. And dammit, I said that I'd bow out...
1_click_off
04-23-19, 15:18
http://everyspec.com/MIL-SPECS/MIL-SPECS-MIL-A/download.php?spec=MIL-A-8625F.002377.pdf
This is a little dated, but it addresses what is acceptable touch up anodizing. I have a few lowers that I would question if they would pass, but I have no plans to take them out in saltwater daily. They are from a well know company. I was surprised to see the touch up on them.
I am almost of the mindset that manufacturers call their items blems when they are overstocked or they need some cash flow. I have never purchased a blem and was actually able to find the blem.
Androctonus
04-23-19, 15:47
Yeah, corrosion isn’t likely an issue. I’ve got a piston upper that got a bunch of cam pin wear at first. It freaked me out, but it’s since stabilized and doesn’t change appearance. The bare aluminum is always covered in oil. It was a blem and has a very small dent. I wouldn’t be surprised if the overstock thing held true sometimes though.
http://everyspec.com/MIL-SPECS/MIL-SPECS-MIL-A/download.php?spec=MIL-A-8625F.002377.pdf
This is a little dated, but it addresses what is acceptable touch up anodizing. I have a few lowers that I would question if they would pass, but I have no plans to take them out in saltwater daily. They are from a well know company. I was surprised to see the touch up on them
F is actually the current revision, there was an amendment in 2003. But yeah, specs. There's specs for process control monitoring, coating thickness and even design including what to do about dimensions and holes!
6.10 Design information.
6.10.1 Surface dimension of parts. On specifying the thickness of coatings,
especially for the Type III coatings, allowance must be made for dimensional
increase. Both a machining dimension and a coated dimension should be placed
on applicable drawings. An increase in dimension, equal to one half of the
thickness of the applied coating, can be expected for each surface coated due
to surface growth. For example, for a 0.004 inch (4 mils) coating on close
tolerance parts, a pre-machining allowance of 0.002 inch (2 mils) per surface
must be made prior to hard coating. If close fits are specified in design
drawings, buildup in thickness caused by anodic coatings, especially Type III,
may result in interference on assembly.
6.10.1.1 Holes. In the case of small holes and tapped holes, coating
thickness can vary from no film to a full normal coating. Holes, both tapped
and not tapped, over 1/4 inch should be anodized. Parts with Type II
coatings, external or internal, with a total tolerance of 0.0004 inch or
less, if lapped, honed or stoned to size after anodizing, should be
subsequently treated with QPL-81706 materials to provide surface protection.
Discoloration on the surface that has been sized is acceptable (see 6.6).
The designer is cautioned to require adequate thread and hole sealing
operations in subsequent assemblies as may be required to produce the
necessary corrosion resistance.
I think it’s pretty obvious that DD runs parts on the low end of tolerance: People seem to bitch more about slop than a tight fit requiring a punch to get the pins out. Second, anodizing is colorless; dye is added. The absence of color does not necessarily mean they cut all of the anodized material away. And again, even if it were, the oxide layer that forms on the bare aluminum is harder than the steel pins.
F is actually the current revision, there was an amendment in 2003. But yeah, specs. There's specs for process control monitoring, coating thickness and even design including what to do about dimensions and holes!
Pin holes are .250. Reads like what DD is doing is completely within milspec.
I'm just a hobby assembler, but if you get a rifle from me it will have the anodizing at the front of the receiver gone because I lap that portion of the receiver to square it as much as possible before installing the barrel. Does this help? I'm sure some, IDK how much, but I enjoy the process.
I'm not a fan of lapping the nose of the lower receiver, but at least it's not a moving part.
Bare aluminum against steel in the pin holes, you are setting up for bimetallic corrosion, etc. And long term, potentially increased wear.
I would not accept receivers that required this, nor do I believe it ia mil-spec. For good reason.
This is not cosmetic, it's a dimensional fit issue.
Less of an issue than cutting M4 feedramps after hardcoat, but same generaal theme.
If it was sold as a blem and the buyer was aware it would be fine. But if sold as a first-line product from a fairly expensive manufacturer? I'd be asking for my money back.
When you can get $50 uppers and lowers that fit well and are dimensionally in spec, there is not justification for a premium mfg to do this.
Androctonus
04-23-19, 22:21
There are some Colt 6520 uppers floating around with M4 feed ramps factory cut after anodizing. I doubt Colt would do that if it presented a functional issue. Colt finish can suck, but they build solid rifles. If somehow I have an issue with the pin holes, I'll have DD replace the upper. But, I've heard there are a lot of uppers and lowers out there like this. Couldn't find anyone complaining yet of any function or fit issue.
It bugs my OCD, but so did other finish wear spots before I just stopped letting it get to me. Those other things have remained non-issues. Have a piston upper that eats into the sides of buffer tube lips. Shiny aluminum there, but it's stabilized. I freaked out, talked to the well respected manufacturer of the expensive upper and they showed me a photo of one of their test fire lowers. Same wear in the buffer tube, thousands of rounds through it. I don't love the wear, but non-issue, the rifle chugs along without a hickup.
Pin holes are .250. Reads like what DD is doing is completely within milspec.
That's an assumption, that standard as written is not clear. I'd have to submit for clarification: =/< .250? As measured or per print/drawing? Don't get me on my soap box about "should" vs "shall". Also, lets not assume that this spec is applicable to the M4's TDP, it might be, but I don't have it to look.
What's amazing to me is folks making excuses for this stuff or saying that it doesn't matter. It may not cause a malfunction, at the very least it's an indicator to me that they're willing to cut corners in a willful and systematic way. That coupled with now knowing that they don't have any external pressure (industry certification/ISO) to maintain good quality processes and continual improvement raises red flags to me. But what do I know, I'm just the corporate quality manager for 4 machine shops, a quality consultant and ISO/API lead auditor.
Outlander Systems
04-24-19, 09:54
OP, both my DDs are like this. You'll be fine.
It's certainly not the prettiest thing in the world, but the fitment between upper and lower on the two DDs I have are the tightest of any AR I've handled.
Despite what Sry0fcr says, your upper will not spontaneously explode, crack, warp, rust, corrode, exhibit massive POI shift, become wobbly and cattywampus between receivers, etc.
Have a piston upper that eats into the sides of buffer tube lips. Shiny aluminum there, but it's stabilized. I freaked out, talked to the well respected manufacturer of the expensive upper and they showed me a photo of one of their test fire lowers. Same wear in the buffer tube, thousands of rounds through it. I don't love the wear, but non-issue, the rifle chugs along without a hickup.
Carrier tilt is an issue that seems to have plagued many retrofit uppers, few have dedicated the engineering resources to prevent it. Including the well respected manufacturer of your expensive upper. You should expect more.
Despite what Sry0fcr says, your upper will not spontaneously explode, crack, warp, rust, corrode, exhibit massive POI shift, become wobbly and cattywampus between receivers, etc.
My issue here isn't that pin holes are going to wear out, I suppose that it's theoretically possible but not likely. My issue is that those receivers are basically rejects that were half-ass reworked and sold off as 1st quality at a premium. We as consumers shouldn't accept this just like you shouldn't accept unstaked carrier keys, and rifle barrel extensions with M4 receivers.
Please don't misrepresent what I'm saying.
Androctonus
04-24-19, 13:27
Carrier tilt is an issue that seems to have plagued many retrofit uppers, few have dedicated the engineering resources to prevent it. Including the well respected manufacturer of your expensive upper. You should expect more.
I’ve read all about carrier tilt. The wear is not in the typical spot indicative of tilt and an anti-tilt buffer tube wears just the same as a mil spec one. The manufacturer claimed it was due to bolt carrier bounce. But, lots of people have these rifles, use them quite a bit, and no one has had an issue that I know of or had to replace a buffer tube. Anyway, this is getting off topic, so I’ll stop.
OP, both my DDs are like this. You'll be fine.
It's certainly not the prettiest thing in the world, but the fitment between upper and lower on the two DDs I have are the tightest of any AR I've handled.
Despite what Sry0fcr says, your upper will not spontaneously explode, crack, warp, rust, corrode, exhibit massive POI shift, become wobbly and cattywampus between receivers, etc.
Thanks. Good enough for me.
I’ve read all about carrier tilt. The wear is not in the typical spot indicative of tilt and an anti-tilt buffer tube wears just the same as a mil spec one. The manufacturer claimed it was due to bolt bounce. But, lots of people have these rifles, use them quite a bit, and no one has had an issue that I know of or had to replace a buffer tube. Anyway, this is getting off topic, so I’ll stop.
I think it's on topic RE: Accepting manufacturing/design defects. You even admit that it was enough of an issue for you to "read all about carrier tilt" and that you contacted the manufacturer about it. They just convinced you that it was okay because all of their guns do it. Obviously there's some kind of tilt, otherwise the carrier wouldn't be impacting your receiver extension...
The irony of the parallels between the anodizing and receiver extension damage isn't lost on me. You see the issues, just can't seem to hold anyone accountable for it... Any QA manager worth a damn wants your feedback, if we don't know about the problem we can't make anyone fix it.
I'll bow out seriously this time, I've lead you to water...
This is ARFCOM levels of goofball. There is nothing at all wrong with that upper.
There is at least one other sane person here. Thank-you for restoring my confidence in humanity.
Speaking as a quality manager, your statement is not correct.
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Just stop, please.
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