We are going to take a short break from the lower receiver and do some work on the upper rear top cover. This piece is what holds the ejector in place and covers the rear of the upper receiver. In the original rifle it also contained the fire control mechanism. Due to the changes that we made to the fire control system it is now installed in the lower receiver.
In the first model reproduction this piece was made with only a single rib.
Pressing is an interesting art and science. While we do everything in solid works their sheet metal program is not actually designed for this type of work. A lot of steps were taken to get to the design that we wanted.
In this first picture is the basic sheet steel cut out that we started with to test the new stamping dies that we made for the pressing of the ribs.
Here are a few pictures of the top cover rib stamping dies.
With the rib design correct and the overall shape correct it was time to test out the next step. This is to bend it into the correct shape for the rear top cover.
This next series of pictures is the actual bending of the top cover. This series was to test the actual die out and before it was installed in a set of die plates.
As a quick side not. The press used in this operation was a 20 ton from Harbor Freight.
Once through this operation the flat will come out with a rounded shape.
But the work does not stop there. Even though it has a basic shape it still needs to sharply defined. This next set of steps shows that being done.
The next post will deal with more on the upper rear top cover. I hope you enjoyed this presentation so far.