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jmart
12-22-06, 10:18
How can you tell if a factory stake job is good enough?

I'll concede that when you visually compare a MOACKS stake job next to a BM or CMT stake job, the MOACKS definitely looks more robust. But is there a standard by which you can evaluate whether or not a factory job is good enough?

Or is everyone just approaching this from the standpoint "more staking is better staking, so I'll have more please".

Harv
12-22-06, 10:59
http://img.photobucket.com/albums/v494/harv24/IMG_1075.jpg

Take a look at these two. Notice the difference??

Even though the bottom one was staked, the level of the staking did not move enough metal against the side of the screw. Now it may work just fine and never give me a problem. But after a few thousands rds and some heating /cooling cycles from rapid fire, it may not be enough meta against he screw to keep it from loosening.

Since a big chunk of AR problem have been documented by many knowledgeable endusers as being caused by a loose gas key, you want the most robust staking job. And the correct way, the Way the TDP lays out is to have it done from the side and not from the top with a screwdriver or any other method. It's something you make sure is done once, done right and then you don't have to worry about it.

jmart
12-22-06, 11:28
http://img.photobucket.com/albums/v494/harv24/IMG_1075.jpg

Take a look at these two. Notice the difference??

Yes, it's obvious. But that's not the question I asked.


Even though the bottom one was staked, the level of the staking did not move enough metal against the side of the screw.

How do you know this?

I realize you are making a comparative analysis based on a visual comparison. It's obvious the upper one is better, but I'm trying to figure out if the lower one is good enough. And try as I might, I've never found a published standard by which one can evaluate the quality of a staking job.

To approach it from a different angle, if I'm not mistaken, carrier key bolts are supposed to be torqued to between 35-40 in-lbs. As long as that torque value is maintained then you shouldn't have a gas leakage problem, corect? In theory (note that I said theory, and that I'm not endorsing this), if one were to loctite screws down with a formula that could take the heat, then screw staking wouldn't be necessary. The combined friction bond of the screw and the mechanical bond of the loctite should be enough to ensure the 35-40 in-lbs of torque is maintained.

Instead we stake the screws. So how much lateral displacement of metal is needed to hold that screw in at the 35-40 in-lb level across all the heat and cooling cycles you mention? How much metal expansion and contraction occurs across these heat cycles?

Or to put it another way, install screws to 35-40 in-lbs. Apply stakes. Now, remove the screw. How much torque should be needed to break the stake and remove the screw? 50 in-lbs? 60 in-lbs?

I would love to know how much it would take to remove each of those screws pictured above, both when brand new and also after having sustained thousands of rounds and associated heat across their lifetime. I don't doubt that the torque values across the life of the screw will change, I just don't have any sense how much they'll change and how much SA usage affects them vs FA usage.

UVvis
12-22-06, 12:55
I think the problem is that there isn't any specific value that one is trying to get. If you were, the measurement might be screwy at best (.1 pie of screw or something?? maybe a hardness measure of the key, then a pressure per particular shaped staking object???) The goal is to move enough metal to keep the screw from moving. That said, more metal moved and jammed into the key screws, the better.

As you pointed out, trying to decide what is "good enough" can be a ton of work. Especially when you have the option of going overkill so you will never have to know if "good enough" is good enough.

rob_s
12-22-06, 15:15
I saw a key staked like the bottom pic come loose this past weekend on a fellow student's gun. I hit it with the MOACKS and it didn't come loose again.

Beyond that it's academic internet drivel.

Stake enough material in from the side such that it deforms a portion of the screw head and you'll be just fine.

Pat_Rogers
12-22-06, 15:26
I saw a key staked like the bottom pic come loose this past weekend on a fellow student's gun. I hit it with the MOACKS and it didn't come loose again.

Beyond that it's academic internet drivel.

Stake enough material in from the side such that it deforms a portion of the screw head and you'll be just fine.

Oh so true! The beauty of the MOACK is in its simplicity and consistency.
A proper staking is not rocket science, and the fact that so many companies fail to do so show just little they are concerned with the end user.

Proper staking is necessary. The MOACK is the best way to do it.
Anything else is just as you said- internet drivel.

Dave L.
12-22-06, 16:50
Oh so true! The beauty of the MOACK is in its simplicity and consistency.
A proper staking is not rocket science, and the fact that so many companies fail to do so show just little they are concerned with the end user.

Proper staking is necessary. The MOACK is the best way to do it.
Anything else is just as you said- internet drivel.

Pat,
Who sells the MOACK and is there any pictures of them?

jmart
12-22-06, 16:57
Ned Christiansen (sorry if I botched the spelling) sells them through his outfit, www.m-guns.com. They run around $100. Kind of a big price to pay if you are going to do a couple of staking jobs.

Does anyone offer HD staking as an aftermarket service? I wouldn't be opposed to sending my carrier to someone, but I'm not sure who offers this service. And, I'm not sure if my key needs a HD staking job, that's why I asked the question if there were an industry wide standard on determining whether or not a stake is adequate.

Internet drivel, perhaps. Call me a skeptic, but I don't think that every factory staking job is as bad as several let on. Again, it's obvious a MOACKS job is absolutely GTG, I'm just trying to determine if my key needs a little additional staking action.

Pat_Rogers
12-22-06, 17:03
Mr Raining,
I did an article on the MOACKS for SWAT a few months ago. You may be able to buy the PDF download.

Submariner
12-22-06, 17:10
Does anyone offer HD staking as an aftermarket service? I wouldn't be opposed to sending my carrier to someone, but I'm not sure who offers this service. And, I'm not sure if my key needs a HD staking job, that's why I asked the question if there were an industry wide standard on determining whether or not a stake is adequate.

Grant, does. See his comment earlier in the thread. Much cheaper than buying the tool.

jmart
12-22-06, 17:31
Thanks, I'll IM Grant but I don't see any response from him in this thread. Are you thinking about a different thread?

Nevermind, I found it in the other thread on bolts and carriers. Didn't realize he offered this service. Thanks for pointing that out.

Harv
12-22-06, 17:45
From jmart

How do you know this?

I realize you are making a comparative analysis based on a visual comparison. It's obvious the upper one is better, but I'm trying to figure out if the lower one is good enough. And try as I might, I've never found a published standard by which one can evaluate the quality of a staking job.

well.... not everything in life is black and white or cut and dry.. How do you know a reserve Chute will work based on visually comparing it to another? You don't, So what do you do... you rely on the skill and experience of others... And that's why I did not want to settle on good enough and send that BCG out to a fellow board member who applied the MOJACKS tool to it ad now it looks like this..

http://img.photobucket.com/albums/v494/harv24/IMG_1114.jpg

Sometimes a visual standard can be the best... along with a little help from some experienced guys who know some things about some things....

It's not always cold fusion.....;)

And that Bolt on the top pic... has 14K thru it...... not a loose key to be found.... that's a clue for me right there....:D

jmart
12-22-06, 17:54
Fair enough. But to answer the original question, it's obvious there's no published standard. It's pretty subjective. Nothing wrong with that, but all I've heard is "more staking is better staking, so I'll have more please". ;)

rob_s
12-22-06, 17:58
Sooner or later you will see "almost as good" fail. When that happens you'll know why "almost as good" isn't "good enough".

In the case of the carrier key that came loose at the EAG class this past weekend, nothing was lost to the shooter except a few minutes of training. However, this particular shooter is in the private security business and that "almost as good" staking job could have failed at a much more critical juncture.

I guess I just don't understand the point of the thread. You know what good enough is, you know what "almost as good" is, but you're wondering why you should bother with "good enough" when you have "almost as good"?

allow me to borrow a line from the Harley crowd;
"If you have to ask, you probably wouldn't understand"

jmart
12-22-06, 18:09
Rob,

Excuse Me for Posting a Technical Question on the Technical Board. Sorry, I Don't Know What I was Thinking.

And if your fellow classmates stake failed, it obviously wasn't "good enough" now, was it. Glad you were there to help th bro out, good on you mate.

BTW, where did I imply "good enough" meant it will hold out for awhile but will eventually fail"?

rob_s
12-22-06, 18:13
You still haven't answered the question. You know what good enough is, why not just do it and move on? Why do you expect to have some standard you can test in newton-meters on some whiz-bang gadget? Just stake the damn thing properly and move on.

This isn't rocket science. You're complicating the hell out of one of the simplest things to do when it comes to ARs, and getting pissy when people tell you so.

jmart
12-22-06, 18:21
No, if you read above after Submariner turned me on to Grant, I said I'd IM him. Which I did. I'm taking care of business, but thanks for caring.

All I asked if there were a published standard. Apparently there isn't. But there's published standards for attaching receiver extensions, barrels, muzzle devices, damn near everything else, so I was just wondering if there was a published PM one could perform to determine if their stakes are GTG. Like apply "x" amount of torque and try to loosen the stakes. If they can hold "x" amount of torque without budging, you are still GTG, otherwise replace your key and restake. Something like that.

When I asked the question I thought my options were to plunk down $100 for a excellent, but in my particular instance, a very limited use tool or to replace my BCG with a known, good one like a Colt or LMT. I wasn't aware that some folks offered restaking as a service. That's good to know.

Stickman
12-22-06, 19:48
Make sure there is enough metal displaced so as to be useful. Look for actual contact, and not just metal being moved on the carrier key.

Robb Jensen
12-22-06, 20:15
rob_s,
no need for religion in this thread (so I edited it out of your post). I also didnt' see where jmart posted 'almost as good', he asked what was the standard, which you couldn't quantify.

jmart,
I degrease the carrier (key area and threads), the gas key and screws with BreakFree Carbon Blast, dry and then torque the screws to 55in lbs, stake with a MOACKS tool and counter stake the screws with a Starrett spring loaded punch. I don't use any Loc-Tite or Rocksett on these screws because if the key ever did need replacing it would take drilling and an Easy-Out to remove the screws. I've never had any carrier key come loose after using my method. At VA Arms we sell a lot of ARs and I restake many of the carrier keys on these rifles before they're sold. The only ones we sell that don't ever need restaking are new S&W and Colt ARs.

uranus
01-03-07, 23:56
This is a brand-new CMT factory BCG. I have another, and the staking is identical. Does the staking seem adequate or should it be re-staked? Is this indicative of CMT's staking?

Compared to the photos in Harv's post, the second post in this thread, it certainly does not have as much metal displaced as with the MOACKS, but there appears to be more metal displaced than in the comparison carrier.

C4IGrant
01-04-07, 11:24
This is a brand-new CMT factory BCG. I have another, and the staking is identical. Does the staking seem adequate or should it be re-staked? Is this indicative of CMT's staking?

Compared to the photos in Harv's post, the second post in this thread, it certainly does not have as much metal displaced as with the MOACKS, but there appears to be more metal displaced than in the comparison carrier.

It is not staked properly and is how all STAG (CMT) carriers look. This is why I personally stake all the CMT carriers that leave my shop.


C4

jmart
01-06-07, 13:07
Grant,

Carrier received. Many thanks for the improved staking job. One less thing to worry about now.

C4IGrant
01-06-07, 13:09
Grant,

Carrier received. Many thanks for the improved staking job. One less thing to worry about now.

Glad you got it ok!

C4