SN63BS hardness? I’m getting 10 on Cabine Tree

[psychbiker]

I think I’m doing something wrong with the cabine tree tester I have. I did buy it used from here bout 2 years ago.

I tested some sb63bs (63 tin 37 lead) and it comes out around 10bhn. Online says it should be higher. I also have been using wheel weight ingots and those are coming in around 9-10bhn.

Shouldn’t the tin/lead allow come out harder?

[Dusty Bannister]

Have you verified the accuracy of the readings with known pure samples?I know that my Cabintree reads a little off at the low end. Lab pure lead reads .032" and the chart shows a range of .020-.030" for a reading of 5 BHN. I usually do not need to know that range of hardness since I work with scrap lead. It is correct at mid and upper range readings.

If you think you may have an error in operation, I found that a thin business card held to the threaded shaft with a small tie wrap helped me keep track of the setting. you may have to sand the tie end down to clear the brass pointer. It needs to be loose enough to rotate on the shaft, but tight enough to not slip when turning the handle to apply one full rotation of force on the sample.

I also follow the LBT instructions in preparing the sample for testing. Sand or file the nose and the base flat. I use a 45-50 cal RF bullet mold for all samples so the reading will be more consistent. The samples are usually aged 2-3 weeks to allow for any hardening changes the alloy might make. Led/tin should not change, but it is still a good idea to double check your samples anyway.

Ingots have their own problems since they have a different cooling rate, and heavy ingots might resist sliding on the base and screw up the reading. The indent should be just touching the sample, apply the load on soft samples and take the reading without delay. Dwell time of the pressure on the soft lead might allow deeper penetration and again mess up the reading.

Once you have validated the readings with pure lead, pure Ly #2 and pure lino, you will know the unit is reading correctly or not. Then you can concentrate on the sample prep and test process. Then you can say, "wow, that is unexpected", but still trust your readings. Dusty

[Dusty Bannister]

To follow up on my earlier post, I tested a factory bar of 63% Tin solder on my Cabin Tree tester and got a reading of .071". According to the sheet with my unit .068 to .070" is BHN 10. .072 to .074 is BHN 11.5. So it might take several readings to get a good average, but quick and dirty this bar is about 10.5 to 11 BHN and decimals are meaningless with these home testing units. When you are taking readings where .002 gives a theoretical change of 1.5 BHN, your expectations exceed the capability of the equipment. Just use it as a guide and be happy. The gun or game will never know the difference.