as a owner of a crown special I try to use a wide field ektar 100mm
is anybody here to help me with the shape or the design of such a cam?
or where I can find it?
or the best precise way to make it?
thank you for all your answer

You'll find two very helpful pages on this site. One lists the Graflex part numbers for the cams it made for top-rangefinder "Pacemaker" cameras (the cam for a 100mm. lens is #29). See

http://www.graflex.org/speed-graphic/top-rangefinder-cams.html

Unfortunately, these things are very hard to find. The few people who (1) have them and (2) know what they are tend to charge amazing amounts of money for one. Your idea of making one yourself therefore seems like a good one. You'll find instructions at

http://graflex.org/articles/oakes/

I've never seen this information anywhere else, and I have been looking for a long time.

Good luck!