Edw. Preston 24″ Patternmaker’s Contraction Rule,

Edw. Preston 24″ Patternmaker’s Contraction Rule, Used By Patternmakers To Make Wooden Patterns A Little Larger So That The Metal Will Cool To The Right Size After Pouring. Two Contraction Scales On The Back, 1/10″ Per Foot For Iron And 1/12″ Per Foot For Brass Markings And The Name Are Generally Quite Faded. It Has An Old Split Down The Middle, Repaired And A Small Burn On The Back. Two Brass End Tips In Good Condition, Brass Pins At The 1″, 2″ And 3″ Marks.