Cabin Tree Hardness Tester

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  • Last Post 19 March 2021
pat i. posted this 18 March 2021

I bought a new hardness tester because I needed a new toy. My question is the new conversion chart is different than the old one. Anyone know why and which is more accurate?

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Duane Mellenbruch posted this 19 March 2021

I am not sure when or why, but the chart I have shows pure lead at .020-.030" and with pure samples from Bill Ferguson, Pure should read .032"  The other samples were Ly #2 and Lino and the test chart and machine did agree with those samples.  Perhaps the chart was changed to update that or more likely there were production changes and the original heavy spring was changed or altered.

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pat i. posted this 19 March 2021

Thanks Duane. So which chart doyou find more correct....old or new? ...

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Duane Mellenbruch posted this 19 March 2021

This is the cross reference I use and have no way of knowing if it is old or new.  By the use of the proven pure metal samples, I have found that pure lead and I assume part of the soft reading alloys might be off a little from the chart.  Lab grade Lyman #2 is correct as is Lab grade Linotype.  As you can see, the numbers are not all that far off, and I try to avoid other errors by careful prep of the sample to be tested.  I also use a large caliber flat nosed bullet to cast test samples to keep it as consistent as possible.  Testing ingots can have a wide range of readings.for the same blend.  My pure lead reads .032" on the test unit that I have.  I suspect there might be some slight error until about mid way between pure and Lyman #2 but have no pure samples to verify that.  It fits my needs very well.

Tester Hardness Cross Reference 

Material            Dial Reading            SAECO            Brinell

Pure Lead*        .020-.030                0                       5

40-1                  .045-.050                5.5                    8.5

30-1                  .053-.056                6                       9

25-1                  .062-.065                6.25                  9.5

20-1                  .068-.070                6.5                    10

10-1                  .072-.074                6.75                  11.5

New WW**      .074-.076                7                       12.5 (est)

Aged WW**      .080-.083                8                      14  (est)

Lyman #2            .084-.086                8.5                   15

Linotype (old)      .086-.090                10                   22

Quenched WW# .090-.095                10.5                23-24

Mono/stereo type .095-.098                10.5-11.5       24-28

Heat treated #       .098+                        12+                32+

Small samples can "spread" giving distorted readings. On bullets, a 1/4" flat filed on the nose works best.  

*When checking pure lead, start the reading as soon as the point touches.  On pure lead, the reading must be taken very quickly.

** WW (wheel wts) vary in composition and your results may vary slightly.  The new WW reading was taken at 1 day and the old was taken after several months.

# Quenched and heat treated will vary a lot depending on your methods.  These are only rough estimates based on what I did. Quenched depends on how fast they are dropped out and water temp.  Heat treated has many variables.

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pat i. posted this 19 March 2021

Duane thanks much. That's the old chart you have which I think I have a little more faith in. I dont know why the charts would change except the new company uses a slightly different spring which would make no sense to me except if it was for some financial reason or they had a different batch of samples. Since its more a comparative tool than a lab grade tool I'll just use the chart you have live long, hopefully, and prosper, again hopefully. Thanks for replying.

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Pentz posted this 19 March 2021

Alot depends on when one begins the reading, e.g. when the point makes contact or when the dial begins to register. Ingots can vary wildly due to differential cooling.

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