Jump to content
I Forge Iron

Rockwell Hardness Tester. Model HR-150A


Recommended Posts

Pretty expensive piece of equipment if purchased new.  I would think every serious bladesmith would want one in their shop.  Probably the majority don't have one, but if you wanted to sell a blade and "claim" a Rockwell hardness number, I'd think you would want to be able to verify your claim.

Link to comment
Share on other sites

I know a lot of bladesmiths who provide a sheet of information when they sell a blade.  It contains method of making the blade, (forging/removal) type of material by name, Rockwell hardness and handle materials.  Those that do that typically use testing equipment such as Jennifer just purchased.

Link to comment
Share on other sites

Few realize that this is a great tool for Blacksmiths, bladesmiths or a tool maker..   Blacksmithing does not need to be low tech.   Understanding metallurgy and what or how a process works and why different steels behave the way they do is good knowledge for all.  

A master blacksmith should understand the concept of heat treatment and be able to apply it both from the stand point of what is happening in the metal but also why a certain axe or chisel or hammer or any hardened tool needs to have a certain shape or edge thickness.    Its what separates a factory made item to that of a custom tool maker. (I'm a custom tool maker as a blacksmith)..  We can give the steel nearly any exact attribute we think it needs to do the job above average.   IE Custom.. 

I took the hatchax out and ran it thru some cutting work both on Dead pine and ash to do some limb work..  Even after each wood, it was sharp enough to peel the skin off when doing and edge check after use. 

I had to harden and temper the blade for how I use it..        Having a hardeness tester is not only there to verify and document but to help others so they can take book work and apply it. 

Real world use is enough for many but in a teaching enviorment the ability to show what is taking place is important to take that book smarts, and boots on the ground learning and put the two together..   This way they can tell someone "Why". Vs I saw so and so do such and such so is the reason I do it.. 

Link to comment
Share on other sites

Dear Jennifer,

Back when I work in the steel mills in S. Chicago we used a Brinnell hardness tester on the material before it was shipped.  It pressed a hardened ball into the steel and measured the deformation to arrive at the Brinnell scale number.  However, the test left a small dimple in the steel.  I assume that this would not be an acceptable result in a custom knife although it would probably be OK in a custom tool.  Has testing progressed to the point that it does not leave a mark on the steel?  If so, do you test different areas of a blade or tool e.g. the back and near edge of a blade, to arrive at an ideal?

"By hammer and hand all arts do stand." 

Link to comment
Share on other sites

3 hours ago, JHCC said:

A less expensive (if less accurate) method is to use a set of hardness-testing files, but a proper Rockwell tester is really the most accurate way to go.

depending on what you are testing, its next to useless on pattern welded material due to its layering

Link to comment
Share on other sites

24 minutes ago, George N. M. said:

Dear Jennifer,

Back when I work in the steel mills in S. Chicago we used a Brinnell hardness tester on the material before it was shipped.  It pressed a hardened ball into the steel and measured the deformation to arrive at the Brinnell scale number.  However, the test left a small dimple in the steel.  I assume that this would not be an acceptable result in a custom knife although it would probably be OK in a custom tool.  Has testing progressed to the point that it does not leave a mark on the steel?  If so, do you test different areas of a blade or tool e.g. the back and near edge of a blade, to arrive at an ideal?

"By hammer and hand all arts do stand." 

Ideally you would test before the final grind/finish so the dimple/depression can be removed.

While this could be a value added feature on making/selling a knife ideally I got it as an educational tool.

My plan is to also have a metallurgical microscope so one can see the differences in the grain structures. 

They now have testers that are non penetration types and are reasonably priced. 

This will show more as to the reason it works.

From an educational standpoint,  visual,  audible,  and theoretical coming together is key.  

And if the tezhing center does not work out, then I'll use it as a sales ploy. Lol

Link to comment
Share on other sites

So one of my buddies who ran a machine shop called me because I had mentioned to him when I was there about his Rockwell hardness tester.. 

This was like 3 years ago..  about 2 years ago he said he was selling off his shop and was I interested in the tester.. I jumped at it and said.. "Of course".. 

That was that..  We never talked about it again..  Back in December we connected and he was like.. Hey, you still want this thing, It's the last thing int he shop and it's gotta move out. 

So, we established a price and I bought it with the word that he had to hold it at his place for a few more months.. Well here we are and now I own a Rockwell tester. 

This model will do A, B and C scale and work on all metals even case hardened ones..   (this might be interesting from a Damascus/layered billet stand point). 

It is a model HR-150A and has all the parts with it and original instruction sheet.  

I bought this to do several different things in the shop..  1,  is to verify the Hardness of items for testing purposes..   2, to show students the results of hardening and tempering and how this effects hardness.. 3,  to put Text book, information into real life application and to understand it vs  the "I saw so and so, do such and such and do it that way."..  

Again, this is a tool for learning..     

 

HR-150A (1).pdf

Link to comment
Share on other sites

Takes me back.

When I first left school I worked in the metallurgical lab of the local armaments factory. I did a lot of hardness testing (samples were encased in a bakelite button about 30mm in diameter and highly polished using diamond paste to remove all surface imperfections). From memory the tests were either Rockwell or Vickers.

They also did tensile testing. It was interesting to see high tensile steel rods of about 20mm diameter being PULLED apart. The machine had a clear safety shield so that you could watch. The test piece would form a slight waist, then come apart with a mighty bang, and the whole machine would jump. No idea how much force was needed. A bloke named Beetle would machine the rod to the correct dimensions for testing. Most of the testing done in the lab was on the pivot pins for the tracks of armoured personnell carriers ("track pins").

The track shoes were cast steel plates with Firestone rubber pads bonded to them. They were bored to take the pivot pins.

The factory is pretty well defunct now. One tremendously knowledgeable  blacksmith that I know ended up with a soft drink (soda?) delivery run. A huge engineering knowledge base was dissipated.

From a workforce of probably five or six hundred they are now down to about thirty people making plastic rifles.

Link to comment
Share on other sites

On 4/24/2020 at 1:54 PM, George N. M. said:

However, the test left a small dimple in the steel.  I assume that this would not be an acceptable result in a custom knife although it would probably be OK in a custom tool.  Has testing progressed to the point that it does not leave a mark on the steel?  If so, do you test different areas of a blade or tool e.g. the back and near edge of a blade, to arrive at an ideal?

From my discussions with Kevin Cashen regarding this, he also indicated that for accurate readings you need to test several times in a location where the steel is flat and parallel with it's obverse surface.  He often tests sections on his riccasso that get covered up by the guard shoulder, so the dimples get hidden.  Since this is the thickest part of the blade, any other hardened sections will be harder (which he has verified by leaving those areas flat on a sample blade or ten and testing those also).  On his takedown blades I believe that you can sometimes see that this testing has been done.  Of course he also uses high and low temperature salt baths for heat treatment and is notoriously anal about metalography.

I missed getting a Rockwell C tester off Craigs list for around $500 recently, and now regret it.  Still they have to be setup properly, calibrated and the testing points need to be correct.  Who knows if a used one would be, unless you are lucky like Jennifer and get one from a friend who had a working shop.

Link to comment
Share on other sites

33 minutes ago, Latticino said:

I missed getting a Rockwell C tester off Craigs list for around $500 recently, and now regret it. 

That's karma paying you back for the great deal you got on your fly press.

The industrial surplus place I get a lot of stuff from has half a dozen or so hardness testers that look interesting. I've avoided them so far, partly because I don't really need it, and partly because of the calibration issue Latticino mentions. However, they also have a soccer ball tester that looks kind of fun.

20191217091127617_L.JPG

Link to comment
Share on other sites

  • 1 year later...
On 4/28/2020 at 12:33 PM, Phil H said:

 

The factory is pretty well defunct now. One tremendously knowledgeable  blacksmith that I know ended up with a soft drink (soda?) delivery run. A huge engineering knowledge base was dissipated.

 

I only found out at his funeral that he had been foreman of the Heat Treatment section. A little bit of his knowledge rubbed off on me, but not nearly enough.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...