One of my hobbies in life is gunsmithing, and one of the platforms that I do a fair amount of work on is the AK-47. I have a really nice parts kit that I'm going to be assembling soon and I wanted a better method of installing the barrel. For those that aren't familiar, and AK barrel presses into the front trunion and is retained by a 7mm pin. On a kit build where the barrel was previously drilled for the pin you have to press the barrel in to exactly where the pin lines up which isn't always the easiest task. On a virgin barrel, you press the barrel in and set the "headspace" (chamber depth), then drill for the 7mm pin. Headspace is measure in the thousandths, so it's a precise process and critical to safety and function.
In the past, I've used an AK-Builder tool in a HF 12T press. It's a 5 handed job to line everything up, it's scary, and you risk bending the barrel or other components if things go wrong. The other popular method is the "all thread" method, which has been used for decades, but is most commonly associated with the tool manufactured by Toth. Toth's tool is very popular as it eliminates the need for a press, is economical, and will push a barrel in and out. There are a few elements of the Toth tool I don't need (I use a Robert Forbus tool for pushing out) and few I tried to improve upon.Basically, you use the side plates to "sandwich" the receiver/trunion in a vise and press the barrel in by turning the big bolt that puts pressure on the muzzle. This allows very fine movement of the barrel compared to a hydraulic press that tends to be jumpy.
My design uses a standard thread protector (14x1LH) that would thread onto the end of a barrel. I used a boring head to mill out a piece of 1.000" round stock to slide on top of the thread protector. On the other side I used a .375" carbide burr (I didn't have a ball nose endmill) to make a dimple to retain a ball bearing. The same thing was done to the end of a 1/2"-20 grade 8 bolt. The carriage is simply 1.500"x.750" cold roll. I originally designed the tool around 5/16" all thread, but I quickly realised I had purchased 3/8"-24 high strength all thread.......
The receiver plates are the same.500"x.750" cold roll material. Dimples were made to clear the rivets by plunging an end mill. The top's received a cut so you can view the barrel pin channel (something I don't think is possible on the Toth tool). The plates were also drilled and tapped for the all thread (another difference). A .100" lip helps line everything up off the front of the receiver.
Here it is all setup on a demilled receiver with a barrel stub.