TexasMac's Web Site
Notes:
1) HB is the same as a common #2 pencil
2) WW (wheel weights) – Depending on the manufacturer, wheel
weights can vary in hardness from 8 to 13 BHN.
3) An excellent high-quality set of drawing/drafting pencils is the
Mars Lumograph set made by Staedtler Mars GmbH & Co. ($10 to $15
at office supply stores). Ranging in hardness from 6B to 4H, the set
comes in a nice thin aluminum box, which is easy to take along when
searching for scrap lead. But other brands of good quality pencils
can be used including mechanical pencils with replaceable cores of
known hardness.
4) For lengthy discussion on the pencil test go to the following link:
http://castboolits.gunloads.com/showthread.php?t=75455
Simple low-cost hardness tester
Finally, if price is the overriding factor, you can make a simple low-
cost tester with a single ball bearing and a vice, as long as you have
access to a small amount of lead or lead alloy of known hardness.
Knowing the hardness of the reference material is the key to this
technique. The results will be at least as accurate as using one of
the commercially available testers noted above.
You’ll need two bottle caps, a vise, a ¼” to 3/8” diameter ball
bearing and a sample of lead or lead alloy of known hardness for the
reference material. Pure lead is an excellent reference material
since it has a known hardness. You’ll also need a caliper for
measurements.
1. Start with two steel bottle caps. Set the caps on a brick and
heat with a propane torch to burn out the plastic inner seals. Let
the caps cool and dump out any burnt residue.
2. Melt enough lead to completely fill one bottle cap with the
unknown sample, and the other with the known hardness reference
lead. The surfaces should be as smooth and flat as possible when the
lead hardens and cools. You may have to skim off some crud or
oxides and re-melt the samples a couple of times to obtain good
surfaces. Allow the samples to cool by themselves (do not quench
with water to speed the cooling).
3. When the samples are cold, put the ball bearing between the
two lead surfaces and squeeze the "sandwich" in the vise until the
ball bearing is driven partly into both surfaces (just enough to make
fair size indentations, but definitely not past the middle of the ball).
4. Remove the sandwich and, using the caliper, measure the
indentation diameters as accurately as possible. Using the following
formula, calculate the hardness of the unknown sample.
Hu = Hr(Dr)(Dr)/(Du)(Du)
...where Hu is the Brinell Hardness Number (BHN) of the unknown
sample, Dr is the diameter of the indentation formed in the
reference sample, Du is the diameter of the indentation in the
unknown hardness sample and Hr is the BHN of the reference sample
Assuming you know the hardness of the reference sample, this
method is as accurate as your ability to measure the indentation
diameters. A relatively smooth surface is necessary to provide a
"clean" diameter to measure. A rough surface will throw off the
answer because you may not get a true diameter to measure. As
noted in the beginning of this article, the BHN value for “pure” lead
can vary. If you're using pure lead as the reference sample, you’ll
have to decide on the BHN value to use.
The measurements should be taken shortly after the samples have
cooled as lead/tin alloys will age soften and lead alloys such as wheel
weights with antimony will age harden.
Wishing you great shooting,
Wayne
1) HB is the same as a common #2 pencil
2) WW (wheel weights) – Depending on the manufacturer, wheel
weights can vary in hardness from 8 to 13 BHN.
3) An excellent high-quality set of drawing/drafting pencils is the
Mars Lumograph set made by Staedtler Mars GmbH & Co. ($10 to $15
at office supply stores). Ranging in hardness from 6B to 4H, the set
comes in a nice thin aluminum box, which is easy to take along when
searching for scrap lead. But other brands of good quality pencils
can be used including mechanical pencils with replaceable cores of
known hardness.
4) For lengthy discussion on the pencil test go to the following link:
http://castboolits.gunloads.com/showthread.php?t=75455
Simple low-cost hardness tester
Finally, if price is the overriding factor, you can make a simple low-
cost tester with a single ball bearing and a vice, as long as you have
access to a small amount of lead or lead alloy of known hardness.
Knowing the hardness of the reference material is the key to this
technique. The results will be at least as accurate as using one of
the commercially available testers noted above.
You’ll need two bottle caps, a vise, a ¼” to 3/8” diameter ball
bearing and a sample of lead or lead alloy of known hardness for the
reference material. Pure lead is an excellent reference material
since it has a known hardness. You’ll also need a caliper for
measurements.
1. Start with two steel bottle caps. Set the caps on a brick and
heat with a propane torch to burn out the plastic inner seals. Let
the caps cool and dump out any burnt residue.
2. Melt enough lead to completely fill one bottle cap with the
unknown sample, and the other with the known hardness reference
lead. The surfaces should be as smooth and flat as possible when the
lead hardens and cools. You may have to skim off some crud or
oxides and re-melt the samples a couple of times to obtain good
surfaces. Allow the samples to cool by themselves (do not quench
with water to speed the cooling).
3. When the samples are cold, put the ball bearing between the
two lead surfaces and squeeze the "sandwich" in the vise until the
ball bearing is driven partly into both surfaces (just enough to make
fair size indentations, but definitely not past the middle of the ball).
4. Remove the sandwich and, using the caliper, measure the
indentation diameters as accurately as possible. Using the following
formula, calculate the hardness of the unknown sample.
Hu = Hr(Dr)(Dr)/(Du)(Du)
...where Hu is the Brinell Hardness Number (BHN) of the unknown
sample, Dr is the diameter of the indentation formed in the
reference sample, Du is the diameter of the indentation in the
unknown hardness sample and Hr is the BHN of the reference sample
Assuming you know the hardness of the reference sample, this
method is as accurate as your ability to measure the indentation
diameters. A relatively smooth surface is necessary to provide a
"clean" diameter to measure. A rough surface will throw off the
answer because you may not get a true diameter to measure. As
noted in the beginning of this article, the BHN value for “pure” lead
can vary. If you're using pure lead as the reference sample, you’ll
have to decide on the BHN value to use.
The measurements should be taken shortly after the samples have
cooled as lead/tin alloys will age soften and lead alloys such as wheel
weights with antimony will age harden.
Wishing you great shooting,
Wayne
| EVALUATIONS & RECOMMENDATIONS FOR LEAD-ALLOY HARDNESS TESTERS By Wayne McLerran |
Last update: 2/6/18
Having participated in online discussions concerning lead hardness
testers some time ago, I thought I’d post some of my comments and
observations here. The threads discussed the preferred tester for
black powder cartridge rifle (BPCR) shooters and the pros/cons of the
four readily available units (SAECO, LBT, Cabine Tree and Lee
Precision). I’ve used all four. But before discussing the individual
testers, the subject of lead hardness and the Brinell Hardness Number
(BHN) should be touched on.
Until recently the BHN value of 5.0 has been assigned to what bullet
casters commonly refer to as “pure” lead. Therefore, three of the
four testers to be discussed are either calibrated to directly read
“pure” lead as having a BHN of 5.0 or come with a BHN conversion
chart based on the same value. More recently, some well-controlled
long-term testing has indicated that the correct BHN of “pure” lead
lies in the range of 4.0 to 4.5 depending on the true purity. 99% pure
lead may measure 4.5 whereas 99.9999% pure lead may approach a
BHN or closer to 4.0, but would be unrealistically expensive for bullet
casters to purchase. I have very recently tested some “pure” lead
and essentially substantiated the above noted experiment. The lead
measured a BHN of 4.2 to 4.3. But the penetration technique used by
the following testers is not a highly accurate method to measure and
determine the true BHN value of a lead alloy. Therefore, attempting
to measure hardness to a decimal point is highly questionable. Hence,
assigning a BHN value of 5.0 may be as accurate as using 4.5.
Fortunately the bullet caster does not benefit from knowing the
hardness to decimal point accuracy. With the above comments in
mind, following are my evaluations of the four commercially available
testers plus a discussion on two low-cost techniques.
The SAECO tester has been around for many years. It certainly has a
small and handy form factor, but will not test ingots and is limited to
shorter bullets unless the bullet is cut shorter for testing. It’s the
highest priced of all and requires using a conversion chart to obtain
the BHN. The chart is based on pure lead having a BHN of 5.0.
Although I have not owned a SAECO, I have tried one and did not like
it for soft alloy testing. It may work fine for the harder alloys
typically found in hard-cast bullets, but is inaccurate when measuring
pure lead or the softer alloys used by BPCR shooters.
Having participated in online discussions concerning lead hardness
testers some time ago, I thought I’d post some of my comments and
observations here. The threads discussed the preferred tester for
black powder cartridge rifle (BPCR) shooters and the pros/cons of the
four readily available units (SAECO, LBT, Cabine Tree and Lee
Precision). I’ve used all four. But before discussing the individual
testers, the subject of lead hardness and the Brinell Hardness Number
(BHN) should be touched on.
Until recently the BHN value of 5.0 has been assigned to what bullet
casters commonly refer to as “pure” lead. Therefore, three of the
four testers to be discussed are either calibrated to directly read
“pure” lead as having a BHN of 5.0 or come with a BHN conversion
chart based on the same value. More recently, some well-controlled
long-term testing has indicated that the correct BHN of “pure” lead
lies in the range of 4.0 to 4.5 depending on the true purity. 99% pure
lead may measure 4.5 whereas 99.9999% pure lead may approach a
BHN or closer to 4.0, but would be unrealistically expensive for bullet
casters to purchase. I have very recently tested some “pure” lead
and essentially substantiated the above noted experiment. The lead
measured a BHN of 4.2 to 4.3. But the penetration technique used by
the following testers is not a highly accurate method to measure and
determine the true BHN value of a lead alloy. Therefore, attempting
to measure hardness to a decimal point is highly questionable. Hence,
assigning a BHN value of 5.0 may be as accurate as using 4.5.
Fortunately the bullet caster does not benefit from knowing the
hardness to decimal point accuracy. With the above comments in
mind, following are my evaluations of the four commercially available
testers plus a discussion on two low-cost techniques.
The SAECO tester has been around for many years. It certainly has a
small and handy form factor, but will not test ingots and is limited to
shorter bullets unless the bullet is cut shorter for testing. It’s the
highest priced of all and requires using a conversion chart to obtain
the BHN. The chart is based on pure lead having a BHN of 5.0.
Although I have not owned a SAECO, I have tried one and did not like
it for soft alloy testing. It may work fine for the harder alloys
typically found in hard-cast bullets, but is inaccurate when measuring
pure lead or the softer alloys used by BPCR shooters.
The LBT tester has also been available for many years. It’s the only
tester that is directly calibrated in BHN (no conversion scale is
required). It’s fast and easy to use, but does not work well on ingots
and is limited to shorter bullets unless the bullet is cut shorter for
testing. It seems to work fine for the harder alloys typically found in
hard-cast bullets, but is inaccurate when measuring pure lead or the
softer alloys used by BPCR shooters. I sold my LBT tester a couple of
years prior to authoring this article, so I’m unable to provide a decent
photo of the unit. You’ll have to go to the LBT web site listed above
to see a small image of the tester.
I own the Cabine Tree Dual Purpose Tester. Cabine Tree LLC offers
two tester models. The Standard Lead Tester is designed for only
testing lead hardness. The Dual Purpose Tester not only measures
lead hardness, but also bullet runout, case concentricity, case wall
thickness and bullet roundness. The testers are extremely sturdy,
very well made and versatile. They will handle just about any shape
of lead, including standard bullets, thin sheets of lead and much
thicker ingots. Testing is fast and repeatable. Another big plus is the
ability to easily recalibrate the testers should something unforeseen
happen such as knocking the unit off the loading bench on to a
concrete floor. Both testers do require a cross-reference chart to
obtain the BHN. The chart is based on a BHN of 5.0 for pure lead. I
really like the tester due to its flexibility and ease of use and can
vouch that Jim Cornaggia (owner of Cabine Tree LLC) is a great guy to
buy from. He continues to support his products after the sale. The
Cabine Tree tester is available through Buffalo Arms.
tester that is directly calibrated in BHN (no conversion scale is
required). It’s fast and easy to use, but does not work well on ingots
and is limited to shorter bullets unless the bullet is cut shorter for
testing. It seems to work fine for the harder alloys typically found in
hard-cast bullets, but is inaccurate when measuring pure lead or the
softer alloys used by BPCR shooters. I sold my LBT tester a couple of
years prior to authoring this article, so I’m unable to provide a decent
photo of the unit. You’ll have to go to the LBT web site listed above
to see a small image of the tester.
I own the Cabine Tree Dual Purpose Tester. Cabine Tree LLC offers
two tester models. The Standard Lead Tester is designed for only
testing lead hardness. The Dual Purpose Tester not only measures
lead hardness, but also bullet runout, case concentricity, case wall
thickness and bullet roundness. The testers are extremely sturdy,
very well made and versatile. They will handle just about any shape
of lead, including standard bullets, thin sheets of lead and much
thicker ingots. Testing is fast and repeatable. Another big plus is the
ability to easily recalibrate the testers should something unforeseen
happen such as knocking the unit off the loading bench on to a
concrete floor. Both testers do require a cross-reference chart to
obtain the BHN. The chart is based on a BHN of 5.0 for pure lead. I
really like the tester due to its flexibility and ease of use and can
vouch that Jim Cornaggia (owner of Cabine Tree LLC) is a great guy to
buy from. He continues to support his products after the sale. The
Cabine Tree tester is available through Buffalo Arms.
The Lee Precision tester is the latest lead-alloy hardness tester to be
introduced for bullet casters. I’m a sucker for new technology or new
apparatuses, especially when it comes to casting and reloading stuff.
So when Lee Precision, Inc. introduced their very reasonably priced
tester (https://leeprecision.com/bullet-casting/lead-hardness-tester/)
had to get one to try it out and to compare readings with the Cabine
Tree unit. I highly recommend the Lee Hardness Tester Kit. The three
components (die, microscope & “V” block) are very well made,
relatively inexpensive and simple to use. It will work on any bullet
length and can be used on ingots with a simple modification to the
setup.
introduced for bullet casters. I’m a sucker for new technology or new
apparatuses, especially when it comes to casting and reloading stuff.
So when Lee Precision, Inc. introduced their very reasonably priced
tester (https://leeprecision.com/bullet-casting/lead-hardness-tester/)
had to get one to try it out and to compare readings with the Cabine
Tree unit. I highly recommend the Lee Hardness Tester Kit. The three
components (die, microscope & “V” block) are very well made,
relatively inexpensive and simple to use. It will work on any bullet
length and can be used on ingots with a simple modification to the
setup.
By the way, having a background in optics, the one thing I always
check for when purchasing an optical device is what the lenses are
made of. It's especially important when cleaning the lenses as some
cleaners can etch plastic. Even with the appropriate lens cleaning
solutions, plastic is softer than glass and therefore more susceptible to
scratching when cleaning. In the case of the Lee Precision 20X hand
held microscope that comes with their hardness tester, the lenses
appeared to be glass, but many low-end optical devices have plastic
lenses these days. Since the instructions did not mention the lens
material and did not address cleaning the lenses, I checked with Lee.
Lee confirmed the lenses are made of glass. Still, as a precaution & to
minimize contamination, it’s a good idea to keep the microscope
stored in a closed plastic bag when not in use.
The chart that accompanied the Lee tester starts at a BHN of 8.0,
which is fine if you’re a hard-cast bullet shooter. Since BPCR shooters
tend to use softer alloys, a chart extending the BHN value down to
around 4.0 should be more applicable and can be used to test for pure
lead. An extended chart is available online and has been passed
around on some of the BPCR discussion forums, but it has
some errors. Using the original chart provided by Lee, I worked up an
MS Excel spread sheet, using it to check the accuracy of the original
chart and also to extend the indent diameters and subsequent BHN
values. See the chart below. Given a specific tester ball diameter
and load, in this case a 5/32” ball and 60 pounds of load or force, the
standard BHN formula was used. A couple of good articles on the Lee
tester can be found at the following links:
http://www.castpics.net/subsite2/HowTo/Leehardnesstester.pdf
http://www.realguns.com/archives/118.htm
check for when purchasing an optical device is what the lenses are
made of. It's especially important when cleaning the lenses as some
cleaners can etch plastic. Even with the appropriate lens cleaning
solutions, plastic is softer than glass and therefore more susceptible to
scratching when cleaning. In the case of the Lee Precision 20X hand
held microscope that comes with their hardness tester, the lenses
appeared to be glass, but many low-end optical devices have plastic
lenses these days. Since the instructions did not mention the lens
material and did not address cleaning the lenses, I checked with Lee.
Lee confirmed the lenses are made of glass. Still, as a precaution & to
minimize contamination, it’s a good idea to keep the microscope
stored in a closed plastic bag when not in use.
The chart that accompanied the Lee tester starts at a BHN of 8.0,
which is fine if you’re a hard-cast bullet shooter. Since BPCR shooters
tend to use softer alloys, a chart extending the BHN value down to
around 4.0 should be more applicable and can be used to test for pure
lead. An extended chart is available online and has been passed
around on some of the BPCR discussion forums, but it has
some errors. Using the original chart provided by Lee, I worked up an
MS Excel spread sheet, using it to check the accuracy of the original
chart and also to extend the indent diameters and subsequent BHN
values. See the chart below. Given a specific tester ball diameter
and load, in this case a 5/32” ball and 60 pounds of load or force, the
standard BHN formula was used. A couple of good articles on the Lee
tester can be found at the following links:
http://www.castpics.net/subsite2/HowTo/Leehardnesstester.pdf
http://www.realguns.com/archives/118.htm
The Pencil Test
Using a set of drawing or drafting pencils of known hardness, for
example, 6B, HB, H, 4H, etc., the relative hardness of lead alloy can
be determined by attempting to scribe the surface using the flat tip
edge of a pencil. Following is a brief overview of the technique:
Start by selecting or flattening a small section of the lead alloy
surface with a file. The base of a large caliber bullet is sufficient.
Prepare the pencils by peeling or removing any wood for a short
distance away from the tip, leaving a short exposed section without
any taper. Next, sand a flat surface on the tip with a file or 500-600
grit sandpaper, being sure to completely remove any taper. The
exposed section should now be a short rod with straight sides, a flat
tip with sharp 90 degree edges.
From the chart below, select a pencil that you believe to be softer
than the alloy. Hold the pencil at 45 degrees to the lead alloy surface
and press firmly forward along the axis of the pencil with the sharp
edge. If the pencil skids over the alloy surface, even if it leaves a
slight scratch, it’s softer than the lead alloy. Work your way up to
progressively harder pencils until you get to one where the sharp edge
digs into the surface, pushing up a curl or mound of alloy in front of
it. Using the largely subjective cross reference chart below, the
hardest pencil that will NOT dig into the alloy is used to determine of
the hardness of the alloy in question.
Following is a tabulation of subjective experimental data, some of
which was reported in a long thread on the Cast Boolits forum with
the understanding that it was accumulated by different untrained
people, using different brands of pencils and on alloys of unknown age-
hardening/softening. At least it provides a rough idea of lead
hardness. As a “coarse” reference, I included lead alloy Brinell
Hardness Numbers (BHNs) from other sources based on the type of
alloy tested.
Using a set of drawing or drafting pencils of known hardness, for
example, 6B, HB, H, 4H, etc., the relative hardness of lead alloy can
be determined by attempting to scribe the surface using the flat tip
edge of a pencil. Following is a brief overview of the technique:
Start by selecting or flattening a small section of the lead alloy
surface with a file. The base of a large caliber bullet is sufficient.
Prepare the pencils by peeling or removing any wood for a short
distance away from the tip, leaving a short exposed section without
any taper. Next, sand a flat surface on the tip with a file or 500-600
grit sandpaper, being sure to completely remove any taper. The
exposed section should now be a short rod with straight sides, a flat
tip with sharp 90 degree edges.
From the chart below, select a pencil that you believe to be softer
than the alloy. Hold the pencil at 45 degrees to the lead alloy surface
and press firmly forward along the axis of the pencil with the sharp
edge. If the pencil skids over the alloy surface, even if it leaves a
slight scratch, it’s softer than the lead alloy. Work your way up to
progressively harder pencils until you get to one where the sharp edge
digs into the surface, pushing up a curl or mound of alloy in front of
it. Using the largely subjective cross reference chart below, the
hardest pencil that will NOT dig into the alloy is used to determine of
the hardness of the alloy in question.
Following is a tabulation of subjective experimental data, some of
which was reported in a long thread on the Cast Boolits forum with
the understanding that it was accumulated by different untrained
people, using different brands of pencils and on alloys of unknown age-
hardening/softening. At least it provides a rough idea of lead
hardness. As a “coarse” reference, I included lead alloy Brinell
Hardness Numbers (BHNs) from other sources based on the type of
alloy tested.