I've not heard of the Bambino, but I suspect it is just a compact version with the electronics built into the tube-thing (a technical term).
They are rebound testers; a electronic Scleroscope if you will. The Tube-Thing has a hard-tipped anvil that is released when you press the button and the electronics measure the height of the rebound. They make a very small indentation that would be un-noticeable on just about any surface except ground or polished ones.
If you control their use and are careful about interpeting the results, they can be useful. They will never replace a Rockwell or Brinell test. They can be very dependent on the operator. They can be very dependent on the size and shape of the piece being tested. They are very dependent on surface condition.
They can be useful. Say, for example, you have mixed two lots of 17-4 PH stainless valves, one you know is heat treated to H900 and the other to DH1150. This tester should be able to seperate them.
Likewise, if you wanted to verify the lobes on a camshaft had been hardened prior to grinding, this tester would work.
If you wanted to verify that a component had been adequately hardened to 32-36 HRC and this device said it was only 30.5 HRC, I wouldn't believe it. Likewise, if it said it was 35 HRC, I would want some other verification of the hardness to base acceptance on.
Most importantly, if you had to work to a Sour Service specification that required, for example, the hardness to be 22 HRC or below, I would not recommend such a tester to verify conformance.
The Equotip is very useful for checking hardness (Leeb scale) on large die blocks that otherwise won't fit in a Rockwell or Brinell. Any specimen that will not rock or vibrate while testing is a candidate for this tester.
Excellent post from redpicker fairly sums up any of the electronic portable hardness testers. Lovely bits of kit but be aware of their limitations. Similar to Proceq is GE-Krautkramer's range of machines:
"Hardness is...not a fundamental quantity of a material but always a response of the material to a certain load or test method. A hardness value is calculated on the basis of the rsponse of the material to this load."
Try to get hold of a copy of GE's "Mobile Hardness Testing" booklet to clarify all the points regarding the difference between the traditional "static" Brinell, Rockwell and Vickers test and the "dynamic" Equotip/DynaMIC tests.
If its portability you require sometimes the non-electronic comparison bar Telebrinell or Poldi methods are best, depending of course on your application.
I evaluated one of the Krautkramer units about 20 years ago when they first came out. It worked well for sorting aircraft brake rotor assemblies where some segments were slightly off spec on hardness. As a metallurgist, I thought it excelled at the task. Unfortunately, our product engineers decided they wanted sorting cabability with the accuracy of a standard Rockwell, something these testers can't deliver.
