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Wilson 3TT Superficial Hardness Tester

Nadim

Plastic
Joined
Dec 11, 2019
Hello,
I'm considering buying one of these older Rockwell hardness testers. Our parts are small (think watch size parts) so I have been advised that the 3TT is the model that will work for me. A quick search on ebay shows some with the designation 3TTBB. Anybody know if there is difference between a 3TT and a 3TTBB?
Also any idea where I can find a manual for these?
Many thanks,
Ned
 
I used a Wilson Tukon hardness tester when I was in grad school in 1963. It had a microscope to spot the location of each reading and to read the indentation length. There was a micrometer X-Y stage for moving the sample precise distances under the lapped diamond indenter. It is exactly what you want for watch-size parts. I suppose the current machines have a TV camera instead of a microscope, but they probably cost a fortune.

Here is one like I used for $2000: WILSON TUKON HARDNESS TESTER | eBay

You do not want a tester that takes C and B scale hardness readings. They are for much larger sample pieces.

You will probably also need equipment to embed the samples in plastic discs and to lap and polish them. The company where I worked had a metallurgical lab with several metallurgists and technicians, so I had many years to hang around and watch them work, and then peek through the microscopes at the samples.

Larry
 
Gentlemen,
Thank you very much for replying. I'll look into both those leads.
Larry, the Tukon one is very interesting with the microscope. I do need the C scale as my parts are heat treated to RC 50+.
Will the Tukon measure into the C scale?
Many thanks,
Ned
 
Gentlemen,
Thank you very much for replying. I'll look into both those leads.
Larry, the Tukon one is very interesting with the microscope. I do need the C scale as my parts are heat treated to RC 50+.
Will the Tukon measure into the C scale?
Many thanks,
Ned

What I meant is that a machine that measures HRC directly is not suited to tiny samples like watch parts because the indenter and the weights are too large.

For tiny samples, the Tukon tester is ideal. It can measure in either the Vickers or the Knoop scale, with the correct indenter and weights. You can convert Vickers or Knoop readings to the equivalent Rockwell C scale reading using a conversion chart.

https://www.nde-ed.org/GeneralResources/HardnessConv/HardnessConv.htm

The Tukon tester I used was set up for measuring Knoop hardness. The Tukon machine can also be set up to do Vickers hardness. Either system is capable of checking very hard steel, much harder than 50 HRC.

Tukon Microhardness Tester - TRL

Knoop hardness test - Wikipedia

Vickers hardness test - Wikipedia Note the "Vickers hardness tester" picture shows a Wilson Tukon machine like I used.

Wilson brand Tukon machines are still made, and they have been modernized to look nothing like the one I used.

Wilson 2100 Tukon Vickers/Knoop hardness tester

https://www.bergeng.com/product/VH1102-1202.html

Check eBay. Here is one in California for $799. https://www.ebay.com/itm/Wilson-Tuk...701821?hash=item4d9412307d:g:yC4AAOSwXitb~qaI

Larry
 
Larry,
Thank you that is EXCELLENT info. From reading your links, it sounds like the some part preparation is necessary. Is that a fair statement?
Our parts range from 0.020" to .120" thick and are typically 3/16 to 1" in diameter. We lap the surfaces parallel to within a tenth typically.
Also, the hardness value is not direct reading but rather but measuring the diameter of the indentation and doing the calculating correct?
DO you recall how big or small the indentation (mainly diameter) is? What is typical for the hardness range I mentioned?

Many thanks. Very useful info. The one in chino is not to far. I may check that out.
Ned
 
Look for a micro-hardness tester capable of outputting direct readings in the scale required. I use a Mitutoyo HM-200 for work similar to yours where I need C scale output. It has a small monitor so the impression can be measured on-screen.
 








 
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