The following link is a google spreadsheet with results that I have gotten hardness testing commercial items and things made in my own shop.
https://docs.google.com/spreadsheets/d/1kAVLe_gU8rzojQmJD50vQnw84yx4-xUeGqHAzscie0g/edit?usp=sharing
The sheet describes the item being tested, the alloy, the hardness result and the date.
For my own items, I’ve added notes partially for my own benefit. These include the method used to heat the steel, and tempering temperature and other comments.
Categories are commercial newer (I have fewer of those tools on hand every day), commercial vintage tools and my own at the bottom.
Most of my own heat treating is fast heat and then quench, with forge shaping of the chisels and thermal cycles prior to quench to decrease grain size. Quenching is done in parks 50 or parks 50 top end and water to finish plus a trip to a -30F freezer at the end.
Testing is done with a portable hardness tester that is a full 150kg force diamond cone (not a superficial tester or non-destructive type ball rebound) calibrated against C scale testing blocks periodically. This tester works by taking a clean polished sample, forcing a diamond cone into the steel with a very specific force and then precisely measuring how deep the diamond was able to penetrate. In similar samples that are flat, accuracy appears to be about 0.5 points of variation.
I will continue to add samples of commercial, vintage and shop made tools.
I have recorded these results with some diligence in operating the hardness tester and do not expect any are inaccurate. If samples have not fit the tester anvil well or provided erratic readings, I haven’t included them here. For example, older laminated stanley irons subjectively read a high result vs. their actual behavior. I would anticipate the cause is the lamination layer being very thin – at or below the limit of what the tester will test, and the soft backing steel of the lamination allows the hard layer to be deflected into the soft steel.
This tester has a lower limit of approximately .045″ of steel, so I cannot test most saws or thin laminated stanley style irons. Solid irons of .08″ or so provide reasonable results. Older laminated wooden plane irons have a thicker lamination well above the minimum thickness requirement. The diamond cone, by reading, indents about 1/64″, and perhaps slightly less in high hardnesses like tools.
Of Making by Hand with Wood and Steel 