Cabine tree tester cross reference graph.

[yammerschooner]

This evening I graphed the tester hardness cross reference for cabine tree testers. Those of you who have one, what do you all think of the jump from 15 to 22?

Anyone tweaked the numbers at all to reflect their experience and make that curve a little smoother? I am guessing the differences are in the plus/minus accuracy values inherent in the machine, but I have found my postulations to be wrong on a semiregluar basis.

http://i69.photobucket.com/albums/i54/yammerschooner/cabinetreegraph.jpg

Here is the info it is reflecting.

http://www.castingstuff.com/tester_hardness_cross_reference.htm

[freakshow10mm]

The jump is apparent. I can't explain why that is. Surely there has to be a measurement for a BHN of 18 or so.

There is overlapping in the 80-85 & 84-86 measurements, but are 1 BHN off, which is insignificant.

I'd make a 80-83 a 15 BHN and the 84-86 an 18 BHN, then the 86-90 a 22 BHN. That's pretty much how I interpret it for my use.

That jump all of a sudden seems weird. Something that should be more linear shouldn't have spikes like that.

[MakeMineaP99]

Lance,

Some constructive feedback.

I'm assuming you have BHN on the Y and alloy type on the X. Wait, upon further review, I see that is dial reading. What are the units on the dial reading? Arbitrary? I'm a bit slow at times, maybe some axis labels are in order for those of us who are stupid?

Interesting data. What would be even more interesting would be another series from the Brinell tester (the real one) showing the accepted hardness values.

[freakshow10mm]

Here's a copy of a post I made on the CT tester on another forum:

I use a Cabine Tree tester. Works off a dial caliper. The depth of impression in the bullet or ingot is measured on a dial caliper and the number is then applied to the supplied chart for the BHN measurement. This can test from pure lead (5BHN) to heat treated alloys at 32+ BHN.
Here it is all set up.
http://img.photobucket.com/albums/v239/freakshow10mm/Boolit%20Casting/DSC02898.jpg
Here the dial indicator is centered on this screw.
http://img.photobucket.com/albums/v239/freakshow10mm/Boolit%20Casting/DSC02900.jpg
The bullet is put in between the pointed screw and flat screw and the screw tightened just enough to hold the bullet in place. To get consistent readings your starting tension needs to be consistent, so I tighten the hold to .002" and then reset the dial face to 0. When the spring is relaxed, it will read .002" off of zero. Put the bullet in. Tighten the screw until the dial show ZERO. Then make the full turn from there. This will give the same starting tension, which is the secret.
http://img.photobucket.com/albums/v239/freakshow10mm/Boolit%20Casting/DSC02899.jpg
The brass pin marks the starting point. Once the bullet is suspended by the screws, turn the pointed screw one full turn, then read the change in depth from 0 to full turn.
http://img.photobucket.com/albums/v239/freakshow10mm/Boolit%20Casting/DSC02901.jpg
After a full turn, we can see the change is .094".
http://img.photobucket.com/albums/v239/freakshow10mm/Boolit%20Casting/DSC02902.jpg

[freakshow10mm]

Applying that to the included chart (probably can't read it here) it indicates an approximate BHN of 27. This is some hard stuff.
http://img.photobucket.com/albums/v239/freakshow10mm/Boolit%20Casting/DSC02903.jpg
You can also test ingots.
http://img.photobucket.com/albums/v239/freakshow10mm/Boolit%20Casting/DSC02904.jpg
This one measures a .091" change or a 23-25 BHN.
http://img.photobucket.com/albums/v239/freakshow10mm/Boolit%20Casting/DSC02905.jpg

[yammerschooner]

Sorry about the lack of labels. I hadn't planned on posting when I graphed the literature out. When I started I was looking to get a better visual representation of the how the numbers played out.

Does Adam's post clear it up a little more?

I haven't taken any readings. The numbers came from the literature that comes with the tester, and it just seemed a little off.

Those dial readings are how much the springed bolt moves in thousanths of an inch as it is compressed. The compression corresponds to various hardnesses.

You are right, I need to hunt down the various materials, take some readings, and get them sent off to someone with access to a calibrated tester.:seeya:


ETA: When do you guys sleep?




Lance,

Some constructive feedback.

I'm assuming you have BHN on the Y and alloy type on the X. Wait, upon further review, I see that is dial reading. What are the units on the dial reading? Arbitrary? I'm a bit slow at times, maybe some axis labels are in order for those of us who are stupid?

Interesting data. What would be even more interesting would be another series from the Brinell tester (the real one) showing the accepted hardness values.

[gokyo]

I may have access to a brinell tester. Let me see if I can get some time on it.

I could do a little comparitve study.

[yammerschooner]

MMP99s got one. By the time I actually get around to getting everything together on this one it will be four months down the road and he will be back to a place where he has accessibility.

With the lead tester repeatability test I have going on right now, I have enough to keep me busy for a bit.