Although swords of this size will vary from warrior to warrior due to the individual's size and
fighting style, the average dimensions are 39 inches from primary blade tip to primary blade tip and 15 to 16 inches from the spine of the sword to the end
of the main blades.
See Image here
To properly size your batleth follow these directions:
Kneel down on the ground (as flat a stretch of ground as you can find). Have a buddy measure you from the top of your head to the ground. This measurement
will give you the tip-to-tip length of your bat'leth. Remember to be on one knee. This measurement is devised so that in the event you take a serious wound
to the leg, you can drop on one knee and continue to fight effectively
Handle holes(pIn'a' and the ghojwI'): - To determine the length of them, lay your hand flat on a table and stretch your fingers out as far apart as is
comfortable. Measure from the tip of your thumb to the tip of your pinkie finger across the back of your hand. This should yield the length of these
"holes". These holes then are as wide at the center as your clenched fist as if punching something.
The Grip: - This measurement is taken from the tip of your thumb to the first knuckle of the thumb add 1/4 inch (6.53 mm). This measurement also yields the
distance between the "holes" mentioned above.
The Width: - This is a bit trickier, but if you can do some basic math, no problem. The curvature of the bat'leth is a 3:1 ratio. Basically, for every 3
inches (7.63 cm) the bat'leth is long, it is 1 inch (2.54 cm) wide, i.e. a 45 inch (114.3 cm) bat'leth is 15 inches (38.1 cm) wide.
The Van: - The tip of the van(s) are 2 inches (5.08 cm) shorter than the tip of the tiq(s).
The rest you are pretty much on your own for.
You should really only need to draw out half of it and then transfer the first half over to make a full batleth.
BTW, these measurements can be found here also:
The origin of this info is from K'Tesh's site which is no longer online.
The site offered great insight on other Klingon weapons.