The Chassis The Frame
Construction and Material Used---the frame is made up of two long straight side members, and front and rear cross members. Side members are made of channel section pressed steel. Front cross member is bent down to form a support for the semi-elliptic transverse spring. Rear cross member is bent upward to fit the arch of the rear cross spring and to add more strength.
Dimensions---Length of side members of the Model "T" 100 inches.
Length of side members of the Model "TT"--- 123-25/32inches.
Width of front cross member of Model "T"--- 23 inches.
Width of front cross member of Model "TT"--- 23 inches.
Width of rear cross member of Model "T"--- 25-1/8" to center line of bracket holes.
Width of rear cross member of Model "TT"--- 32-5/8" to center line of body bracket holes.
Method of joining parts---Hot riveting.
By this method the rivet contracts as it cools, thus filling the hole in frame.
Brackets---These are used to support the body, running boards, truss rods, fenders, lamps, control rod quadrant. They are fastened to the frame by rivets, excepting the fender and lamp brackets, which are bolted.
Truss Rods---Purpose---To give added support to the frame. Are used on running board brackets.
Taken from the Model T Ford Club web site.
http://www.mtfca.com/books/ford.htm#chas
Anything you could ever want to know about a T is on their sire.