Sometimes a plane iron just has to be thin, replacement blades for compass planes for example, where the frog is non-adjustable and the sole is riveted around the mouth so it cannot be filed to accommodate a thicker iron. Or very early US made Stanley models which had perilously thin irons and modification would be detrimental to the value of the tool.
This Sheffield made O1 plane iron is 2.2mm thick, the grinding is a little bit coarser than we are used to, but the hardness is perfectly acceptable at RC60 and the price is just fantastic. Teaming this iron with a Quangsheng or Clifton cap iron will still yield a significant performance improvement versus the original irons.
Standard 1¾" replacement blade for No.3 bench planes and No.080 compass planes and equivalents.