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Testing Hardness

wawoodman

himself, himself
H-M Supporter-Premium
#1
I'm about to try hardening some small parts with cherry red and a torch, since I don't think I can do the furnace thing. So after I'm done, I would like to check the hardness.

I certainly am not going to go for a Rockwell tester. I saw these on the Bay: http://www.ebay.com/itm/TSUBOSAN-Ha...986884?hash=item3600c29804:g:w78AAOSwo3pWgobw

Has anyone used them?

On the other hand, do I need them at all? Will a simple file tell me (more or less) all I have to know?

Happy new year, y'all!
 

4gsr

Global Moderator
Staff member
H-M Supporter-Premium
#2
They work! As long as you don't use them as a saw as I've seen in my past. Just work with the hardest one first. If it cuts, go down one hardness and try again. Chances are it will be hard. But what you have to watch for is, sometimes the surface will be soft for a few thousandths deep. This is called carbon diffusion of the surface when heated in open air. But with a acetylene torch the carbon given off will create an carbon atmosphere around your part as long as the flame is present.

Oh, you can use a file, but if the file is harder than your part it will cut. Some files can be up to around 65-67 HRC. But the heat treat files work quite good. I have a set I snagged off of eBay years back here some where. Where did I put them?
 

bfd

H-M Supporter - Premium Content
H-M Supporter-Premium
#4
I saw somewhere in toolland a set of files for hardness testing these files had a range if hardnesses and if it cut the metal then the metal is not that hard. b ut maybe I'm just dreaming bill
 

BGHansen

H-M Supporter - Premium Content
H-M Supporter-Premium
#5
Grizzly has(had?) them for around $60. I recall picking a set up off eBay (new) for around $40. I've never used them so can't speak to their (or my) accuracy. I didn't find them on Grizzly's web site, here's a typical eBay listing for similar files.

Bruce

upload_2017-1-5_15-1-15.png
 

4gsr

Global Moderator
Staff member
H-M Supporter-Premium
#6
You can test them against a couple of Wilson hardness test blocks or with something with a known hardness. You won't get it down very close, but within +/-5 Rockwell points on the C scale.
 

chips&more

Active User
Active Member
#7
Never tried the files? I do have an Ames hardness tester (pic). Works great! Only drawback is it’s limited to the size of your test samples. But I have not had that problem yet. The only problem I have had is I can’t remember how to use it. It has a certain order of things to do when using it. And I can never remember them! So I have to look at the instructions each time I use it!...Dave
rctester.jpg
 

Hawkeye

Active User
H-M Supporter-Premium
#8
I just got a set of those same ones a couple of weeks ago. Surprised me on a few things I had assumed were harder. I'm glad I got them.