Lee Hardness tester consistency question

[GBCAPT]

I have a Lee Hardness tester, which I finally have figured out how to use thanks to a members suggestion to use a clear plastic bottle as a holder!

I picked up seven C309-150 F bullets from a recent casting session and indented the meplats using my iPod as a timer. The measurements were:

1) 0.062 2) .059 3) .058 4) .066 5) 0.64 6) .060 7) .061 AVG.=.0614

Inspection shows that #4 actually overlapped the edge on a side, and #5 is so close to an edge that some edge deformation is visible. So if I reject #4 &#5:

1) 0.062 2) .059 3) .058 6) .060 7) .061 AVG.=.0600 or BHN 14.3

Do others with more experience with the Lee Tester see similar measurement spreads, and is a 5- 10 bullet sample adequate?

[Motor]

It's kinda hard to use the measuring glass. I didn't buy mine to be pin point precise or to do case lot inspections. I got it so I would have a good idea of how hard my alloy is and it works great for that purpose. It's a heck of a lot better than guessing or using your thumb nail.

I have a mould I made to make a ingot for a special fishing sinker I make. This ingot has a flat on it that is perfect for the Lee tester. So the only time I really measure my hardness is when I'm getting ready to cast. I haven't heard of bullets becoming softer with age so if they age harden a little I don't really care.

I can tell you that since I started powder coating I found that I can use 12 BHN for just about anything I cast for from .38spl to 500 S&W and when I empty my pot into a ingot mold the next time I melt that ingot it still measures right around 12 BHN. That's good enough for me.

Motor

[MUSTANG]

The most difficult part of using the Lee Hardness Tester is getting a calibrated Eye Ball. I too use a clear plastic bottle with cap on it to hold the Lee Scope with measurement gauge in a fixed position. I agree with Motor that it is repeatable enough to get a good grouping of alloys (soft, medium, hard, super hard) and applying a number against them. The number might float + or - a fraction; but it beats guessing.

[No Blue]

Try following the instructions; they say to file a flat onto the bullet and do your indentations in the flat. You doing it into the meplat is not gonna work.

You downwind from the Dow plant?

[W.R.Buchanan]

What you are looking for with this tool as a consistent and repeatable method of making the indent.

The way to do this is to adjust the die so that the press goes over center at the bottom of the stroke and the handle stays down. At that point with the plunger is flush with the top of the die you are getting the same spring pressure on the ball every time .

Having the press go over center insures that press is doing the same thing everytime.

The depth of the imprint is then only reflective of the hardness of the material, and not some other flaw in the operation of the press.

This is the easiest method that will deliver consistent readings with this tool. I have one and I use it just this way.

I also have a very big Optical Comparator in my Shop that allows me to take very accurate measurements of the dimples and I can extrapolate Hardness Readings using the chart to .1 of a point.

Randy