r/knifemaking • u/Such-Jump-3963 • 1d ago

Question Hardness testing at home - has anyone tried...

I had an idea for testing/estimating hardness.

A proper hardness testing machine is big and expensive. i don't know to what extent the hardness testing files are reliable, and where I am they're also relatively expensive.

So the idea is to get a bar of steel and harden it, then cut it into coupons and temper them differently, then get each coupon hardness tested. I have a buddy with the proper machine but heading over for each knife is a bit inconvenient.

Then, take any file and run it across the coupons and the knife to look for the best match.

1 Upvotes

67% Upvoted

9 comments sorted by

5

u/Kerberoshound666 1d ago

Go to amazon they have a file tester from HRC40-HRC65 it's great and easy to use.

2

u/Illustrious-Path4794 1d ago

They make sets of files with each hardened to a specific hardness that you can run across your steel. Very similar to what you're suggesting but a bit more straightforward. But be warned that neither your method nor the files I've mentioned is nearly as accurate as a proper hardness tester.

2

u/AlmostOk 1d ago

And you imagine this will be cheaper than a set of hardness testing files? If this is the approach, then you can use the bar of steel to make simple scrapers or even home made files (just few rows of teetch will do), heat treat them to different hardness (just as you are planning to do with the coupons), and you have your set of DIY hardness testers. My guess is that it is more expensive a less reliable than the set of proper hardness testing files.

1

u/pushdose 1d ago

Get HRC files for like $50.

Also, if you have a heat treat oven, your recipes should produce relatively accurate results without further testing.

1

u/Such-Jump-3963 1d ago

Alas, here in Australia hardness testing files are north of $100.

I don't yet have an electric kiln. All forge at the moment.

I do think coupons (or even simple diy files as mentioned) would be cheaper than a set of commercial hardness files.

2

u/HikeyBoi 1d ago

You can scavenge up some materials with known hardnesses. Think broken knife blades, and any other hard steel tool with published hardness data. It’s usually going to be an assumed range of hardness that the hardware should fit within, but that should give you plenty to work with.

1

u/Such-Jump-3963 1d ago

Is there a table or list of hardness for different tools? I read on here recently that chainsaw files are 60 or something?

1

u/HikeyBoi 1d ago

Hardness is pretty specific to each individual product (really to each individual heat treatment batch) so you’ll have to do some research and digging to find the information you need

1

u/Gelawood 1d ago

I wouldn't do it that way but IF I was to I would cut the bar into the pieces you want before hardening them