Hardness Testers - Rebound Type -vs- Traditional Indentation

[Flammable_Solid]

FYI - Wilson is just the brand of the machine. You will need to know what specific hardness tests a machine is capable of and which indenters to get with that machine. Some machines can only do a certain test, some can do multiple types. Also, figure out on the design of the axe where you want to check the hardness at and if it meets the requirements for thickness, flatness, parallelism, from the specs I listed earlier.

For what hardness testers cost and what it costs to keep them calibrated, most people just get parts tested at an outside lab.

 

[Tony Wells]

Out of the literally thousands of tons of various materials I have had heat treated, NONE of the HT'ers use rebound testers. You have to wonder why. One reason I can think of is the decarb layer. Not all materials have a significant decarb zone, and it can be virtually eliminated by controlled atmosphere so it's not always an issue. Many finished parts do not allow penetration marks, hence the practice of a test coupon. This also can be kept for future reference in case of a squabble with the customer. Most of the forgings and hot rolled Q&T has a considerable decarb layer, and this must be ground through leaving a reasonably flat area to test. I've used a chain-on tester for large diameter stock, and several benchtop testers, but always following strictly the ASTM guidelines applicable to each hardness range and material type. There is actually quite a bit involved in making legitimate hardness tests.

All that aside, the hobby machinist probably doesn't need all that traceability and super accuracy stuff. A rebound tester is not a new idea, and is acceptable in many cases. If you examine your needs realistically, and it meets your requirements, you can sure save some money.

 

[countryguy]

Thanks for all the good feedback folks. We're heading up to the local reseller/Lab place (Sun-Tec) near us. Owners Son is going to have us bring up the Kids stuff and we'll see what we can do. Nice guy to offer! To ames units look really cool! But they seem scarce on the used front. My final 3cents is that so many used and so many unknowns from the ebay and 'refurb' places- We're in no rush. Just wondering, learning, and checking into things. Thanks again, CG.