Author Topic: Hardness Tester  (Read 2226 times)

Offline tangler

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Hardness Tester
« on: October 08, 2015, 05:18:25 PM »
Hi Folks,

I've not been posting much lately since I've not been doing much that is relevant to MEM.  The wood working (a chitaronne) has not been going too well so for a bit of light relief I've made my hardness tester using the castings I bought last summer:





It's a Vickers hardness tester to a design by Dave Lammas published in Model Engineer in 1989.  I managed to get a standard test block for not too much on ebay;  I went for mid range 46.4 Rockwell C.  I measured the hardness on my machine at 454 Vickers.  According to a conversion table this is between 45 and 46.7 HRc.   :cartwheel:  Well chuffed or what.  Clearly testament to a good design.  Well done (the late, sadly) Mr Lammas!

That paintwork looks awful in the photo  >:(

Cheers,
Rod


Online Jo

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Re: Hardness Tester
« Reply #1 on: October 08, 2015, 07:17:44 PM »
My hardness testing is not as accurate:  :-[ It normally consists of trying a needle file on the surface and if it skates across it then I count that as success  :)

Jo
Enjoyment is more important than achievement.

Offline jadge

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Re: Hardness Tester
« Reply #2 on: October 09, 2015, 10:42:22 AM »
Rod: Doooh, having seen the same picture on another forum I've now realised who you are! Ah well, us country boys are a bit slow, and we're almost in the Fens here.

The hardness tester looks really neat, and made me dig out and read the original articles last night. It is also interesting that you are getting good results; that's encouraging. I have a full size tester that works on the same principle, as a result of a 'bother I won it' episode on Ebay. However, I have no manual with it, and while I understand the principle of operation I've never got to grips with it. Your posting has given me a bit of a kick to get on with it. Currently I use a set of specially hardened files to test hardness. They work, but go up in steps of 5 Rc, so are not particularly accurate. They are enough to tell me that I've failed to harden something properly though.  :-[

Andrew

Offline smithdoor

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Re: Hardness Tester
« Reply #3 on: October 13, 2015, 02:09:17 PM »
Great job and looks great too  :cartwheel:

Dave