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Senior Member
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".
Member
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.
Senior Member
Yes, it's obvious. But that's not the question I asked.Originally Posted by Harv
Take a look at these two. Notice the difference??
How do you know this?Even though the bottom one was staked, the level of the staking did not move enough metal against the side of the screw.
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.
Member
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.
Former Member
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.
Firearms Instructor (R.I.P)
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.
Senior Member
Pat,
Who sells the MOACK and is there any pictures of them?
Senior Member
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.
Firearms Instructor (R.I.P)
Mr Raining,
I did an article on the MOACKS for SWAT a few months ago. You may be able to buy the PDF download.
Senior Member
Grant, does. See his comment earlier in the thread. Much cheaper than buying the tool.
"The very purpose of a Bill of Rights was to withdraw certain subjects from the vicissitudes of political controversy, to place them beyond the reach of majorities and officials and to establish them as legal principles to be applied by the courts." Justice Robert Jackson, WV St. Board of Education v. Barnette, 319 U.S. 624 (1943)
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