Rockford Ram Hardness Tester

[Ductmate]

We have a Rockford Ram Hardness tester in our shop, model 30-R. The rollformer line operators use it to check the hardness of our steel (mostly galvanized). It's never been calibrated to my knowledge but the operators know what the usable range is.

Someone lost the ball out of the indenter that they were using, so I'm not sure what size it had. The only replacement balls we have are 0.062" dia. The one they were using may have been 0.125".

I have little experience with hardness testers like this, so I was hoping someone could shed some light on which indenters we should be using and what difference the size makes.

From the chart i've seen, we're measuring on the Rockwell E scale around 70-80 or so.

I tried finding some info on this tester on line, but had no luck.

Thanks,
Vince

 

[lgearhart]

I always find it SO much easier to make those kinds of decisions when I know more about the topic. That's why I'd recommend you download your FREE copy of NIST's practice guide to Rockwell Hardness Measurement of Metallic Materials. Go to

http://www.msel.nist.gov/practiceguides/SP960_5.pdf.

Remember that a larger ball will test over a larger volume of material, so it'll average better, and be less sensitive to minor surface variations.

 

[Flesh]

Go to the following link:

http://www.hardnesstesters.com/rockwell-scales1.htm

A 1/8" ball is used for the "E" scale. With a 1/16" ball you will now be measuring on the "B" scale. This is under the assumption your minor and major loads have not changed.