Sticky LBT hardness Tester

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  • Last Post 07 December 2010
Fg1 posted this 04 December 2010

Made up a 20# batch of alloy and when testing a sample bullet to get an idea if it was close enough I found that my tester was sticking . Then real slowly the needle would rise .:shock:

After adding a hunk of babbit to sweeten a bit i poured several bullets for checking . Filed the bases just enough to ensure no little bumps from spru to interfere.

Same thing every time , it would stick and drag slowly raising. It would always stop a touch above 15 after sweetening with the babbit .

The lever/bar is clean but has some little scratches from the indicator dragging so I think Ill stone it some then buff with dremel and rouge.

Anyone else run into this ?

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CB posted this 04 December 2010

A couple of things First your bullets need to age a bit before you will get anything close to an accurate reading.

Second you must release the arm slowly, a rapid release will give an erroneous reading.

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Fg1 posted this 04 December 2010

I do the slow release when letting the arm up . It looks like the little indicator arm is sharp on the end and has been digging in . I have had and used this since 87-88 a lot . Surprised it isnt wore out !

At any rate I was blending alloy and needed to get somewhat of an idea where I was in hardness . Ill recheck in a few days but need to fix that dragging first.  

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CB posted this 04 December 2010

just so you dont ruin it, go to verals website and ask him what to do, I am sure he will help you out. http://www.lbtmoulds.com

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Fg1 posted this 04 December 2010

Ill give him a holler on monday .

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JetMech posted this 05 December 2010

Any hardness tester should/will specify a dwell time that the penetrator is in contact because exceeding that limit will lead to false readings. My Cabin Tree tester does the same thing. Checking some linotype I got from RotoMetals, it read correctly when I first applied pressure according to the instructions, about 22BHN. 5 minutes later, it was reading around 15BHN. Take the reading within the first 5 seconds and you should get the correct reading. The softer the alloy, the faster the reading will change.

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Fg1 posted this 07 December 2010

Well , I took a piece of flannel and buffed the spot on lever/arm then dusted it with white motor mica . Tested some bullets other day with it from the alloy I mixed and it showed right at 15 bhn. I filed indents away and tested today and get 17.5-18 bhn. Thats after 2 days .  

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CB posted this 07 December 2010

Well that sounds much better... Looks like you cured your woes.. I would see if you can quantify that result with another tester so you know your result is accurate.

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Fg1 posted this 07 December 2010

I only have the one I got from Veral 20 some years ago . It doesnt do the sticky thing no but moves smoothly . The motor mica is slick stuff ! Ill just keep it and the little shaft dusted with it that the springy indicator rides on . The bullets “clack” pretty good when you tap the noses together so their pretty hard. They dont have a dull 'thud' to them . Pretty scientific observation ......huh .>.> :firefire:fire

Im knew to this age hardening thing with the alloys . Have always in past since beginning not give it much thought . Just cast after reaching a reasonable bhn, inspect , lube , load and shoot .

So , what would be a good rule of thumb timewise for when the bullets will stabilize as far as hardness ?

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Dale53 posted this 07 December 2010

My “rule of thumb” is two weeks. They will continue to age harden but it nearly all will be finished in two weeks.

A good friend doesn't have a hardness tester. He had some certified bullet metal and wanted to see if the hardness was “as advertised". He brought some bullets to the club. They all measured softer than they should. I asked him when he had cast them. He said he had cast them that day. I told him to bring them back in two weeks. He was dubious but agreed. The next time, the hardness was “AS ADVERTISED".

Dale53

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Fg1 posted this 07 December 2010

At this rate if it goes to 20 bhn I might just back off the babbit sweetener a little bit .

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