Topping Off Uneven Boxes

Unregistered

Dear anyone who might help,

I have these pyramid looking boxes that are going to have cement poured in them. They are 40 x 40 inches on bottom and 24 x 24 inches on top. There is an open top and bottom. How would I go about chopping off an uneven top. The edges don't all fit exactly right. Some are higher and some are lower. I am trying to figure out how to easily mark it all the way around as well as what to use to cut it with

Sincerely,

A guy who doesn't know what he is doing

Unregistered

Place the boxes on a level surface, say a sheet of ply or similar. Find the lowest point at the uneven top and level a line across that side of the pyramid. If you measure up both edges to the line, they must be equal. Then just measure up all the edges and place a mark the same measurement as before. Join up all the marks round the pyramid and cut with a sharp hand saw. Buy one especially if neccessary, a hard point saw is fairly cheap now. Start cutting across a corner first towards the middle of the two faces - watching that the saw stays on both lines on each face, do that on all corners.
Finally finish cutting through all faces. Finish with a sharp block plane or medium glass paper. Good luck.

Unregistered

Just one thing, the above is not always so: it will be if the angles of the sides are all the same, but given that the tops are higgledy piggledy, the side angles might vary as well.

The above may well work perfectly well, but I'd prefer to use a level to extend the initial mark all round, rather than measure up, then you know it will be right.

Regards, NT