Hardness measured by bounce height... could be a project

[bkbville]

Here is an interesting hardness test by the Canadian Youtuber "AvE" (His videos are quite interesting and entertaining.)

He's measuring hardness by bouncing a bearing ball in a clear tube and measuring the height of the bounce to determine the hardness.

https://www.youtube.com/watch?v=qUpape0XgVs


At the end of the video he identifies that such a device does already exist.

Still, it gets the brain thinking...

A more limited range of BHN measurement - maybe up to 30 BHN? I think it could be used for testing bars of alloy; not sure how practical on the base of individual boolits.

Optical sensors could be used, triggering as the bb passes, each spaced at the heights correlating with BHN steps, the sensors would be connected to a micro - maybe an arduino - and displayed on a screen.

[NoZombies]

Unfortunately ingot hardness usually doesn't correlate to finished bullet hardness because of the differences in cooling speed. We used to bounce ball bearings off of anvil faces to get an idea of the rebound.

[Tazza]

As soon as i read the post heading, i was going to say there was a video by AVE that talked abut this, good to see you watch his vajoes too

The one issue i see is that the test material needs to be flat and on a hard surface to not loose any energy from the impact, so no cushioning.

[Alstep]

Here's some interesting stuff on hardness testing.

http://www.gordonengland.co.uk/hardness/scleroscope.htm

[44MAG#1]

Mountain molds has or did have a description on how to make a hardness tester with a ball bearing and the math to use to figure out the hardness. I did it and got very good results after first using it on old lead that probably is closer to "pure" than this reclaimed stuff listed as "pure". Even tested some non burned out Linotype and got extremely close results. If you have a loading press you can make the tester. It doesn't require someone smart to make it or to do the math. If it did I would have not been able to do it.
The Mountain Molds tester is probably more accurate in the long run.

[KMac]

Just looked at Mountain molds and the article is still there:
https://www.mountainmolds.com/bhn.htm
Pretty interesting.

[popper]

Actually I'd just hook a mike up to a steel plate and listen to the 'ping'. Could run it through a FFT on the computer and see the difference. Like a trucker hammering his tires to check for pressure.

[RogerDat]

One of these days I might buy an actual hardness tester but since they run $75 to purchase I decide for now I'm using artist pencils (sticky in the Lead and Alloy forum) By taking known alloys (XRF gunned or foundry) and using an artist pencil I can determine hardness. Then use a cheap spring loaded center punch, sometimes called a prick punch to make a dimple. Not exact but I can repeat the same dimple on an item in a scrap yard and determine if it looks like BHN of soft, somewhat hard, fairly hard, hard, or freaking zinc that someone threw in the lead bin. Prick punch with its spring just makes making the dimple repeatable, the pencils give me a BHN number for known lead.

[Larry Gibson]

Some years back I was pretty good at telling the hardness of a drop zone by the height of the bounce........

[popper]

Larry, how hgh does the Abrams bounce?

[Larry Gibson]

Larry, how hgh does the Abrams bounce?

Depends on the hardness of the dop zone........