Converting a Milled M70 Front End for a Sheet Metal Receiver Using Screws

Ok, let’s take the heresy a step further.  In a previous post I described taking a milled stub and welding it to a sheet metal receiver.  Another approach is to drill, tape and use alloy screws.  So, let’s talk about that a bit.  I did this build back in 2010 also.  I actually still have the rifle and it’s one of my most reliable AKs.  It takes about any ammo I stuff in it and I don’t recall ever having any issues.

For those of you who are wondering why I didn’t do rivets – I was bored and wanted to try something different plus this is a range gun and not something mission critical.  Here we are 7 years later and it’s still doing fine – no cracks, no loose screws … but it isn’t stressed either.  When in doubt, do rivets or a milled gun.

In terms of this build, I milled the trunnion down the same as I did for the weld build.   I used my Hungarian AMD trunnion as an approximate guide for locating the holes and used two #10 screws for the front top and a 1/4″ for the rear.  In both cases, I opted for national fine.  10-32 and 1/4-28.  So, for 10-32, I used a #21 drill bit to make the hole  and for the 1/4-28, I used a #3.

For drill locating and drilling the receiver holes, I used the AK-Builder trunnion rivet locating jig.  You just put the trunnion on the jig, locate the hole, slide the receiver on and drill the hole.

Now for tapping, being square is a good idea.  I squared my table to the drill press’s chuck and used it to hold the tap.  I use Tap Magic cutting fluid to lubricate everything.

For the screws, I used alloy button heads and secured them with red thread locker.  I reached in with a Dremel and ground down protruding screws.

So there’s the front.  I used an air riveter to do the trigger guard.

I’ll post some more on this build in future posts.

So, here are some links for you:

 

#3 drill – these are expensive on Amazon.  Before you buy any drills or taps from Amazon, check out McMaster, MSC and other industrial sources first.  I used to get a lot from Enco but they were acquired by MSC so I pretty much look at MSC and McMaster for cutting tools plus a few specialty items from other places.

AK-Builder Trunnion Hole Jig

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