The Front sight is very easy to reassemble.
Start by simply pulling the front sight on to the
Gas Cylinder's dovetail. Note that the thicker part
of the sight is to the rear.
If you have marked the Gas Cylinder
with a Sharpie Marker when you took the sight apart,
you will line the sight up even with the mark. Marking
before disassembly lessens the guesswork when reassembling
and makes re-zeroing the rifle much easier.
The next step is to
simply drop the Front Sight Screw into place into
the rear portion of the Front Sight at its base.
When the screw is in
place turn it clockwise with fingers until it is
too far down into the countersunk hole to grab and
then I finish tightening it with a 3/16 inch Allen
Wrench (aka: Hex-Key).
Tighten the sight down
very snugly and use Lock-Tite so as to keep the
screw from backing off.
The photograph below shows the Front Sight
fully assembled and in place on the M1 Garand Rifle.
Now, reassemble the Rear Sight.