Spent some time digging in the dirt today, getting the area in front of the rear chamber rake out hole squared away (literally).
It had been an eyesore, work blockage (wheel barrow always got stuck in the depression), and health hazard (rocks roll down inside and then you step on them, twisting your ankle).
I had some left over wood pieces and brick laying around, so I spent a few hours digging out the square and setting the frame in, then wedging it in with old brick fragments, etc… The digging was the hardest part, I was determined not to have to cut wood and as luck would have it it worked out that way.
At some point in the future I suppose I will lay some concrete in there sloping up and away from the hole, for maximum raking pleasure.
This gives you a vague idea of the original state of the pit.
Here it is finished, second pic with castable hole cover in place.
When not in use, a plank or two can be plunked down for easy passage, or alternatively punji stakes can (cheaper than bear traps) be set in the floor to catch unwary neighborhood kids who ignore warnings not to play in the kiln area.