What Size Drill Bits For An Ak Front Sight

In Part 5, I finally got the barrel headspaced, drilled and pinned into the trunnion that I had previously riveted into the receiver. My AK-74 projection was finally looking similar it would turn into a functional rifle.

The side by side step is to fit the rear sight cake, gas cake, and front sight block onto the barrel, and so drill and pivot them into place. Because the process is very like to drilling and pinning the barrel, and in that location's no headspace to worry nearly, I thought this step would be easy. The reality turned out a lilliputian more complicated.

The first problem I ran into was discovering that my American-made barrel was a bit oversized for my Bulgarian-fabricated rear sight block, gas block, and front sight cake. The lower handguard lock slid hands into place and locked upward at the pre-cut notches, but everything else was a few thousandths of an inch as well tight. Then I fell dorsum on skills I picked upward when I fitted a also-tight gas cake onto an AR-15 butt.

Not And so Fast

The outset trouble I ran into was discovering that my American-fabricated barrel was a fleck oversized for my Bulgarian-fabricated rear sight block, gas block, and forepart sight block. The lower handguard lock slid hands into place and locked up at the pre-cutting notches, but everything else was a few thousandths of an inch too tight. Then I savage dorsum on skills I picked up when I fitted a besides-tight gas block onto an AR-15 barrel.

Sanding The Barrel

I bankrupt out the Emery cloth, brass rod and ability drill, and began sanding. Offset, I hand sanded the specific locations on the barrel where the various parts would fit. I put the barrel into a vise, gripped the strip of Emery material at either end, and sanded using a "shoe smoothen" motion. I counted the strokes, doing l each from the 6, three, ix and 12 o'clock positions effectually the barrel to make sure I was taking off equal amounts of metallic from the whole circumference.

Sanding the 12 o'clock portion of the barrel near the gas port.

After doing 50 sanding strokes from all four directions, I paused to measure the barrel bore with a micrometer. Information technology took a few cycles of sanding each area of the butt to remove but a thousandth of an inch of metallic.

Sanding The Parts

Once the specific areas of the barrel were sanded, I removed it from the vise and replaced it with the rear sight block. This time, I put a strip of Emery cloth into the end of a slotted contumely rod and chucked the other finish of the rod in an electric drill. I then sanded the inside of the sight block's butt channel, making sure to move the rod back and forth, letting the Emery fabric wear evenly on the within.

After 100 back-and-forth strokes, I paused to micrometer. When I had removed a thousandth or then, I repeated the procedure on the inside of the gas block and the forepart sight block.

Finding A Bigger Hammer

Later on sanding, the rear sight cake slid into place later on a few advisedly-aimed whacks with a large, dense safe mallet. The central to proper rear sight block placement is to make sure the little "ears" on the bottom of the block slide within the respective little ears sticking up along the edges of the front trunnion.

There will be a little space to piece of work with, and so look down the barrel from the rear of the receiver to make sure the rear sight block looks as centered as possible. And so tap information technology into place until the rear edge of the sight cake is flush with rear edge of the front end trunnion. I learned this lesson the hard fashion - more nearly that in Function 7.

The rear sight block in place. — The rear sight cake in identify, ready to be drilled and pinned. Here, information technology'south easy to see the extra-shiny portion of the butt that'south been sanded downwards.

The gas block was trickier because the gas port in the block must align with the gas port in the barrel, or the rifle won't office. The Bulgarian gas block has a squeamish piffling hole cut in the underside of the block, directly contrary of the gas port in the block. All I had to do was apply a permanent marker to make a dot on the underside of the butt in line with the butt's gas port, and and then hammer the gas cake into place until the dot appeared in the centre of the hole. It sounds elementary, just it took quite a few hard smacks with the mallet to attain.

Just like the rear sight block, the just way I found to keep the gas cake vertically aligned was to frequently look downwards the length of the butt from the rear of the receiver, and eyeball it. If it looked crooked, I used the rubber mallet to tap it left or right until it looked directly again. As the gas block got close to its last position, I was able to utilise the gas tube and the gas piston to check and recheck terminal alignment before vigorously borer information technology into identify.

The front sight block was both piece of cake and difficult to properly marshal. The like shooting fish in a barrel role was finding the correct spot forth the barrel. I just tapped it into identify until the muzzle was affluent with the mouth of the threaded opening on the block. Vertical alignment was more than difficult, considering if the front sight block is off center, the rifle'south point of aim will be skewed.

Front sight block aligned flush with muzzle. — Front sight block aligned flush with cage.

Again, the best technique I constitute was to hold the barreled receiver up to my cheek and sight down the butt, looking for the forepart sight to exist in the exact centre of the rear sight. Adjustments were as simple as taps to the left or correct with the rubber mallet, but it proved very piece of cake to give one tap too many. Centering the front sight block took several minutes before I was satisfied it was correct.

Rear sight block, gas block, and front sight block are all finally in place, waiting to be drilled and pinned.

Same Erstwhile Drill

Once I was satisfied that the rear sight block, gas cake and front end sight block were all tapped into identify and correctly aligned, the barreled receiver went back to the drill press so I could cut the final notches into the exterior. This step was very fast and simple compared to sanding the barrel and the parts, then knocking them into place with the prophylactic mallet, all while constantly pausing to cheque for right alignment.

About to drill the pin hole for the rear sight block. — About to drill the pin pigsty for the rear sight cake.

Metal chips fly as the first gas block pin hole is drilled. — Metal chips wing as the first gas block pin hole is drilled.

Final hole drilled to pin on the front sight block. — Final pigsty drilled to pin on the front sight block.

The hardest part was finding a style to hold the barrel withal under the drill press so that the drill flake would get straight through and not wander around, particularly with the front sight block. I got some help from Jake Weikert of the Brownells R&D Department, who's been giving me technical guidance through this projection.

To choose the correct-size drill flake, Jake and I merely visually compared the drill bit diameters to the diameters of the corresponding pins. One time we found a close lucifer, the bit zipped through the border of the barrel very nicely, and minutes later nosotros had tapped and pressed in all the pins.

All parts pinned onto the barrel, and gas piston, gas tube and spring installed.

Painfully Close

What used to exist a collection of grease-covered parts in a box now looks even more like a completed AK-74. Next month, I'll install the hammer and trigger, and add together the buttstock and pistol grip. Then I need to go out to the range to sight in the rifle and give you a complete range study.

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