Here is a long delayed progress update.
I had to correct (change) many things on the fly:
1. the back side was cut long time ago when the hatch design was not thought out. As i started working on the hatch frame, I realized the bottom of the hatch won't even close as it was cut. So I some changes.
Here is pic before the hatch change, the hatch can't close on the bottom:
I rounded off the back side sharp edges, and more importantly, i cut a straight 1.5 inch vertical section on the bottom, now the hatch bottom can close, i'll have to deal with the near 90 deg bend for that 1.5 inch section when I skin and trim it
2. removable fenders, I welded fenders and some steppers along the frame, I realized they will interfere with the final skin install. So I changed the fenders and steppers to be removable.
with this, I can work on the skin not worry about the fenders. I welded some sleeves to the frame, the fenders will be slotted and bolted on.
3. I initially installed interior 1/8 birch ply skin, but I didn't know 1/8 ply has direction, i forced it on the wrong way, it's so rigid, I couldn't make it to confirm to the shape. I only accidentally found out the ply direction as I was mindlessly bending a small cut out piece. So i had to remove the skin, all the brad nails, and redo it
I guess you live to learn...
Now as I start on the insulation and wiring, I'm facing anther dilemma. I have 2 porch lights, the wires need to stick out to the outside. Do I need to install the exterior skin before wiring? otherwise, it can be a challenge to pull out the wires when install the exterior skin.