Turned out okay so far.  Here's a brief photo

assisted explanation of building those doors.

Pine or Oak, or Maple or almost anything - even Sweetgum.  I didn't want my doors to be heavy so I used 1/2" pine. Use boards of sufficient length to fit door opening well (no kidding sherlock!) .  I like to build mine a little extra tall and wide and then cut down a little after.

For instance if the opening is 32 inches I will build it 33 or so inches wide and then cut it to fit later.  That way if the opening or the door is a little out of square - who will know!

On the photo on right, I have made a mark, then lined up my saw with the mark and I am using the square to help hold the saw straight.  I usually hold the square across the top but I had to remove my hand for the photo.

In picture on the right, notice that the horizontal cross pieces for the Z's are equally spaced from top to bottom (well close to equally). 

Also, notice in photo to right and below, that the horizontal pieces are not all the way to the edge.  I leave about 3/4" from the outer edge.  Final outer edge that is.  Remember, we added extra width so we can cut it down later to fit more perfectly.  Thus, we need to leave 3/4" plus the extra. 

ALSO...I used two of the half inch pine boards stacked on each other to make the horizontal & diagonal parts of the Z's.  So, in fact, my Z parts were 1 inch thick.  Needs to be strong to hold the shape.

Popping a line for straight screwing.

What order should I put the Z parts together. 

First put the horizontal boards of the Z's together. 

Once I cut the horizontal boards of the z to length, I used my square to help me place it at a 90 degree angle or perpendicular to the outside vertical boards. 

I then squeezed the boards together.  Sometimes I might use a bar-clamp for this or a friend to push the boards from the other side while I push from mine.  Or, if really desperate, I just use my own strength to pull them together.  When they are tight together I put a  screw or two in each vertical outside board to hold them together. I measured 1/2" from edge to place the screws.   

To give a nice straight screw line, simply pop a chalk line right at the desired place for the screws.  This makes screw placement fast & accurate. 

shameless plug:  check out my invention the Hold-It on my drill to the left.  For more info visit www.bit-grip.com.

After horizontals are secured in place, simly lay the z diagonal in place and mark.  

 Make a mark on each side.  Notice the V mark.  V-marks are much better than one straight line.  It is much easier to mark an exact point and then find it later. 

On the right, you can see that I have marked both sides of the diagonal's end.  I then repeat this at the other end without moving the board at all. 

Next,  I turn the board over, draw a line that connects the two marks and cut with a table or circular saw.

Continue with the second diagonal if you are doing a DOUBLE-Z DOOR.

We're getting close but sometimes casual observers aren't that excited about the process.

At this point, you should have all the pieces cut and in place. 

Completely screw the door pieces down. 

I used 2 rows of screws on each board guided by the chalk lines.  I spaced my screws fairly close together because it really helps hold the door together and helps the thin (1/2"pine) wood maintain its shape.

I put the door together and stood it in front of my opening to check the fit.  If it was too large in place, I simply mark the offending parts and cut them off. 

That sounded weird huh?

To right:  Tired Daniel with (almost) finished double z door.  Needs more screws and hinges though.  See photo at top for ideas on hinges.