During the 1920s, steel shafts reinvented the game.  Wood was the only shaft material known to the game across the previous centuries, except for a few failed attempts to incorporate metal into shaft construction.

Offered here is a Spalding Olympic "O" model putter with a square steel shaft and unusual blade shape. The back of the head is stamped with the club's name and a variety of Spalding's markings along with patent information. Produced under a US patent issued in 1916 to Edwin Hamilton Winkworth Scott, the Spalding O putter is among the absolute earliest steel shaft clubs that a collector has any sort of reasonable chance to obtain. It was initially offered in Spalding's 1915 catalog. 

Straight as the day it was made, the 37 1/8" shaft is square across its entire length and the grip is old, dating back to the day this putter was in use.  The round grip has been built up under the left hand to assist the golfer.  Note that the grips on Winkworth Scott's own square steel shaft putters were typically square.

Scott also received a British Patent for his club in 1912 and 1913, long before the USGA's 1924 resolution legalizing metal shafts under USGA rules.  It was not until 1929 before the R&A changed their rules to allow metal shafts.

TCA2 V 2 p 656-657