This post will go through the steps necessary to machine one of the lower receiver. I was going to do a video, but there was not much to see with the coolant on.
If you remember the last post on the lower receiver we had finished welding it up and it looked like this.
Now comes the part where we remove everything that is not part of the rifle.
First a couple of pictures of the fixture that was made to do machining. You can see that this fixture will support and clamp in the receiver securely.
What we are going to do is clamp a receiver into the fixture.
The first step is to install a center support for the receiver.
The it is clamped into the fixture.
We do this to mark it so the excess can be plasma cut off prior to machining.
You can see the magic marker on the sheet metal where it was plasma cut. You can also see the 3 holes that were drilled to allow clamping the front and rear clamping blocks
Now it is back into the fixture for machining.
After a slow and careful machining op, sheet metal has a tendency to grab the end mill and come out of the fixture. We are finished with this phase.
A couple of close up pictures of the receiver after machining but still in the fixture.
This is how it looks coming out of the fixture and prior to de-buring.
This how they look after the initial de-buring.
After the receiver is cleaned up a final machining operation is conducted on the manual milling machine to clean up the inner area of the receiver.
With this operation we have gone from rough weld up to a finished machined part ready for the next operation.