Pencil hardness testing methods

[oley55]

Although I have already digested the "lead pencil" sticky in it's entirety some years ago, I seek some clarification on the method/process.

Should I be looking for a shaving of lead, just a gouging of lead, or gouging with attention to the pencil's destruction/deformation? I ask because I processed some 400#'s of roof flashing/boot lead a month ago which should be in the pure lead range (I think). Today after having filed off the surface of a couple ingots I set about scraping the lead with pencil tips sanded to a flat sharp edge and held at a 45 degree angle pushed across the lead.

The 5B (7-8 BHN) pencil made a gouge without totally destroying the lead tip. The 6B (4-5 BHN) pencil made a gouge but the pencil point crumbled as it was pushed across the lead. Both distorted/altered the surface of the ingot, but which one is the best indicator of hardness?

[Wheelguns 1961]

I am not an expert on this form of testing, but have been using it for over a year or so. You definitely want a gouge in the lead. I would say that your 5B pencil are the results you are looking for. I haven’t experienced the point crumbling before. Maybe it is due to your actual point. Maybe you are pushing too hard. I am curious to what others say also.

[414gates]

Your lead hardness is closer to the 6B. You probably have close to pure lead. If the 6B didn't dent the surface, but the 5B did, it would be 5B hardness. The softest pencil that marks the lead is the lead hardness.

I used this when going out to buy ingots. It's a quick way to approximately confirm the claimed hardness.

You just need to put enough pressure with the pencil tip so that either the lead is deformed, or to confirm the pencil does not dent the lead surface.

Pushing the lead tip over the lead surface at an angle to maintain friction without breaking the pencil tip or sliding it is what you aiming for.