Formerly it was the practice to change the gear on the end of the Reversing Shaft or the one between the Reversing bevels.
"Illustrated Catalogue of Cotton Machinery"
Howard & Bullough American Machine Company, Ltd.
Tools used for forming the angles of two adjoining surfaces, are squares and bevels.
"Woodworking Tools 1600-1900"
Peter C. Welsh
If bevels, use ratio radii .
"Modern Machine-Shop Practice, Volumes I and II"
Joshua Rose