The question about staking came up in another thread. Rather than derail it, I thought I'd start another. I originally posted this in another forum.
I work on aircraft and my job that I take a variety of training courses to remain current with up to date techniques and get refreshers on others. On of the most recent refreshers I had to take was on staking and I thought I'd share some notes-
It's very easy to over-stake the endplate so that the endplate crushes into the threads of the RE. You want just enough material pushed into the castlenut slot to keep the nut from loosening from vibration. A little bit goes a long way. A couple of small stakes are better than crushing the endplate and damaging the threads of the RE. Over-staking the gas key can damage the bolt heads enough they'll shear which will FOD out your rifle with broken partsStaking must be done carefully to avoid damaging parts
If you make the staking on either the endplate or the gas key too deep, the displace material will crack and won't hold anything in place. It's particularly important with the gas key for two reasons. First, the gas key is harder and more likely to crack than the endplate. Second, if the head of the screws are too small for the counterbore, staking deep enough to contact the heads of the screws will crack the displaced material. Make sure the heads of the screws are the right diameter before staking the gas key and don't over do itThe metal that is displaced must not separate from the parent material
When staking, try to position the tool to be "normal to the surface" or as close to 90* as practical. If the angle is off, the raised edge will be higher on one side than it is on the other. But don't over think it. Sometimes, the staking tool has to be angled a bit to push the displaced material in the direction it's needed to go.The raised edges around the staking impressions must be of even height and there must not be any burrs sticking out
The raised edges shouldn't have any burrs. Burrs are the result of staking too deeply, or from staking tools that are too sharp, pointy, rough or jagged such as a thin bladed screwdriver, nail, center punch with a point like a scribe or needle, or a tool with a tip that's deformed or broken. A burr is material that's ready to break away and reduces the effectiveness of the stake
Basically, this is to ensure the staking tool used leaves a clean, smooth, regular shaped stake. To leave a smooth, regular shaped stake, the tool must be smooth and regular shaped. The use of a jagged, broken or irregular end is not acceptable because it will damage the part. Proper staking tool for the end plate and gas key will have either a circular (round), or rectangular, end.Staking impressions may be of one of three shapes- Small circles, small rectangles or small rings
(Small ring staking is applied with a special staking tool that presses a ring around the perimeter of the part (such as a bearing) and won't be used on the endplate or the gas key. I included it because it was part of the course.)
I know many of you old pros know this stuff already, but the newcomer with a fistful of questions should find this handy. Use a smooth, clean staking tool, go easy, plan your work and you'll get a good stake every time
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Originally Posted by JM Campbell
