Knoop Hardness Chart? - Wilson Tukon M30 model
03-20-2008, 03:26 PM,
 ExtremeCoatings Active Member Posts: 13 Threads: 6 Joined: Jul 2007 Reputation: 2
Knoop Hardness Chart? - Wilson Tukon M30 model
I was wondering if anyone could lead me in the right direction. We have purchased and Microhardness tester for one job in particular and to save some money we bought a dinosaur Wilson Tukon model M30. I have instructions but it discusses a chart which I do not have in relation to the KHN. The manufacturer no longer has any documentation in regards to charts for this.

We have no experience with this technology and we have gotten to the point where the machine makes the indentation, but now the calculation part is not working. Maybe someone could give me a quick run down on how to proceed after the indentation.

Russell
03-20-2008, 04:04 PM,
RE: Knoop Hardness Chart? - Wilson Tukon M30 model
Hi Russel

For measuring Knoop hardness KHN, after making indentation with a specific force, measure the long diagonal only. Usually you would convert this measurement using conversion tables supplied with the equipment, but you should be able to use other Knoop conversion tables as the method is pretty universal. You can also use a conversion formula.

Visit https://www.gordonengland.co.uk/hardness...rdness.htm and you will find the Knoop formula and a calculator to make things easier. I will have a look around to see if I've got any tables, trouble is many pages covering all the different applied forces, so maybe problem copying and posting.

Also, this instrument should be capable of Vickers hardness testing by simply changing the diamond indenter. Visit https://www.gordonengland.co.uk/hardness...htm#hvcalc for Vickers formula and calculator
03-20-2008, 07:00 PM,
 ExtremeCoatings Active Member Posts: 13 Threads: 6 Joined: Jul 2007 Reputation: 2
RE: Knoop Hardness Chart? - Wilson Tukon M30 model

I think I am having a problem figuring the mm from the filar units.

Instructions say to take Filar units x Objective Factor which equals microns and then multiply by 0.001 to get mm.

Next step is to read corresponding KHN from chart(which I don't have)

I am pretty sure I am measuring using the Filar correctly but after that I am having the issue in calculating.

The Objective factors I have are 10x, 20x, and 50x.

03-21-2008, 02:57 PM,
RE: Knoop Hardness Chart? - Wilson Tukon M30 model
Hi Russel

I can't remember actually using a Tukon tester before, so bear that in mind

I think the objective lens factor (correction for eye piece Filar measurement) is not the same as the objective lens magnification ie x10, X20, X50. Usually, (could be wrong with your model) the standard measuring objective lens will be X50 giving you an image magnification of ~X500 with a x10 eye piece or X625 with a x12.5 eye piece (x100, x200, x500 or x125, x250, x625 magnification sets). Using X50 objective I would expect the Filar units to be directly in micrometres ie correction factor x1. The X10 objective would have correction factor x5 and x20 objective x2.5.

It would be wise to check/calibrate the optical measuring system using a accurate stage micrometer or with micro samples of known dimension. That way you know for sure how to convert your Filar units. Then do some hardness checks using a calibrated hardness test block.
03-21-2008, 07:46 PM, (This post was last modified: 03-21-2008, 07:47 PM by ExtremeCoatings.)
 ExtremeCoatings Active Member Posts: 13 Threads: 6 Joined: Jul 2007 Reputation: 2
RE: Knoop Hardness Chart? - Wilson Tukon M30 model
Thanks again Gordon. You are right about calibrating.

I talked to manufacturer again and they got a chuckle that someone is still using this model.

So I kinda know what I need to do next and after that using your links I should get it.

03-21-2008, 09:46 PM,
RE: Knoop Hardness Chart? - Wilson Tukon M30 model
Hi Russell,

It might be a bit of an antique, but sure it will be fully functional and might even out live some of the modern day plastic stuff
04-18-2008, 03:04 PM,
 ExtremeCoatings Active Member Posts: 13 Threads: 6 Joined: Jul 2007 Reputation: 2
RE: Knoop Hardness Chart? - Wilson Tukon M30 model
Gordon Wrote:Hi Russell,

It might be a bit of an antique, but sure it will be fully functional and might even out live some of the modern day plastic stuff

Thanks for your help Gordon. We finally figured out how to use this dinosaur. We have sent our sample that we tested out to make sure we are accurate with our readings just to make sure we have it solved.

-Russ

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