For shade tree mechanics who want to replace the L5 timing belt by the book and don’t want to buy a cam lock tool, here is how I made my own:

Materials:

2” x 3/16” angle steel about 9” long.
Flat tool steel about 2” wide and 6” long (an old lawn mower blade works fine)
Nuts and bolts
Sharpie for marking positions
Painter’s tape
I used a metal cutting disk on a skill saw for all cutting and a hand drill (The bits don't last long)

The slots in the camshafts are in the right position parallel to the top of the cylinder block and in line with each other. This makes the tool much easier to build.

Cut the angle steel to the width of the back of the motor.

Cut two short pieces of tool steel for the blades to fit into the camshafts. I used an old lawn mower blade. The thickness was just right. A short piece of the hot rolled angle steel will work but if you try to remove the VVT units with it the torque will bend the blades like a pretzel (how do I know this?)
Hold the angle steel against the back of the motor and dry fit one of the blades to the top. Mark the position with a sharpie, the drill two holes in both pieces and bolt them together. Repeat the process for the other cam.

(Note: the intake cam slot is a little higher that the exhaust cam slot. I compensated by bolting on the left side blade with a washers as spacer.)

Hold a piece of paper against the back of the motor. Tape it to the motor at the bottom and press it against the top two motor mount bolt holes to mark their positions Dry fit the tool against the motor, pull and crease the paper over the tool, and tape the paper to the tool at the top. Now you have a template for drilling the holes to bolt the tool to the motor.

It’s not pretty but I used it successfully to remove and replace the VVT units and timing belt.