The early samson posts were usually 8 to 10 feet high. The center of the walking beam balances in a saddle on the post and moves freely due to a center pivot. Thus the up and down motion of the walking beam can be achieved as soon as a pitman, bandwheel and power are hooked up (see illustration above). The early walking beams (before standardization) were 16 to 20 feet long and about one foot thick in the middle.
By 1884 the standardization of the wooden drilling rigs (the standard cable tool rig) was clearly achieved and the specifications of a carpenter's rig was in print as noted in an Oil Well Supply Company (Pittsburgh and Oil City, Pa.) catalog of that year. However, slight variations were still present depending upon the rig builder (or manufacturing company) and, later, on the region where it was to be used such as California, Appalachian Basin, Canada, etc.
The standard rig walking beam was 26 feet long and was 12 inches wide by 26 inches thick in the middle and bevelled to one foot or 14 inches square at each end. The samson post was 13 feet high, 18 inches by 20 inches thick at the base and 18 inches square at the top.