Testing hardness with pencils

[Blublister]

I have been reading about building a hardness tester for some time and never got around to building it. Im glad I didn't get to it since now I only have to sharpen some pencils. This is the new sliced bread. Great info!!! Thanks

[meshugunner]

Agree. Staedtler brand is the ONLY one to buy, and they do cost from $12-16. Let's not go all cheapash here!!!! Just spend the money. After all, you are squealing out of buying a $160 Cabine tester!

Do not use any thing but the recommended brand because they are repeatable time and time again. Staedtler pencils, so I have been told, have been used by the paint industry for many decades as the field test for paint hardness, so they are made uniformly. Not like brand XYZ you buy on the cheeeeeeep from "your guy" or WalMArt or a swap meet.

bangerjim

I draw with pencil and have complete sets of about 20 different artist's brands. There are *NO* standards, one mfr's HB might be another's B etc. Also, with cheaper brands there can be uneven steps in hardness and inconsistency between batches. I completely agree with banger - use Mars Lumograph pencils. They are high quality, consistent and fairly easy to find. Also you will be able to compare your results with those of other people. Sheesh we are talking about a few dollars difference in price for something that you want reliable and consistent.

[mike 30-06]

Lee makes a good and cheep lead hardness tester kit. Chapter 10 in lee's modern reloading second edition describes how lead hardness can be matched with chamber pressure to produce most accurate and non barrel leading loads. The same manual gives 1 grain reduction factor for both projected speed at muzzle and pressure. Both can be calculated with limited rifle cartridges and powders. No 1 grain factors are provided for pistol.

Mike

[Traffer]

I've been reading all the various posts about methods and devices for testing alloy hardness. One post by Molly recommended using pencils of varying hardness to compare against the surface hardness of bullets and ingots. This is widely used in labs to test hardness of metal coatings by scratching the surface in a particular way to see if the pencil digs into the surface or glides over it.

After some searching, I found that Office Depot, a large chain of stationary stores here in the US, carries just what I needed - the Staedtler Mars Lumograph set of pencils for artists. Cost is $10 for the set of 12 wooden pencils in a flat metal case, already sharpened, ranging from 6B to 4H.

Molly said 6B pencils are same hardness as pure lead and H equal to linotype. Can anyone provide an approximate BHN number for the other pencils in between? These are 6B, 5B, 4B, 3B, 2B, B, HB, F, and H. The set continues on up to 2H, 3H and 4H, but if H is lino, I won't be using alloys any harder than that. BTW, I tried out the pencils on the base of a fresh bullet cast from what I believe to be Lyman no 2. F scratched the surface, but HB just left a trail of graphite on the shiny surface, as predicted.

I really like this method. Its quick, cheap and repeatable. No spring loaded devices, no ball bearings, no measuring indents with a digital caliper. Just apply the pencil and see immediately if it scratches or writes. You assistance in converting the pencil numbers to BHN is appreciated. thx - CW

This is what I have for hardness:

Hardness Reference

Pencil BHN Common Alloys
7B 4 pure & sheet lead
6B 5 lead wire
5B 7-8 40:1 Golden Bullet
4B 9 25:1
3B 10 20:1 WW, My Casts
2B 11-12 Range Scrap
B 13
HB 14-15 Lyman #2, 1:1 Linotype
F 16-18 Commercial cast bullets
H 20-22 linotype/WW, linotype
2H 26-28 Monotype, Quench WW

[rhouser]

You know, every now and then a topic comes back up and it is a good thing.

Molly's threads on pencil testing led me to buy a set of Staedtler pencils some years back and I have been using them ever since.

Today, I pulled a bag of about 500 .32 cal 94 gr PB commercial bullets with absolutely no markings what so ever on the bag and no memory of when I bought them. I am loading them into a 32 Mag for use in my rifle. I pulled out my pencils and polished one with a B but cut it with HB and an F. I now know that I can jump the velocity's into the 1000 FPS range without too much leading. I have some cowboy action bullets in 32 that can get messy if I get into the high 800's

My point is that Molly gave me a useful tool that I use when I am not sure of a group of "muffins" hardness (cause at 65 I sometimes forget). I marked them 6 or 8 years ago when I alloyed them for my use, but, sometimes the markings wear off etc. I use the pencil testing to evaluate my current starting points etc.

Thank You Molly if you are still out there.

v/r rch

[6622729]

Greatest idea yet! I hate my Lee hardness tester. The pencils are so easy to use!!! You can try to use the pencils empirically (that means actually try to put a hardness number to the test by the chart created in this thread) or at an absolute minimum have a great super fast way of comparing two samples to one another.

I tested some COWW I have in ingot form against some ingots I received that were claimed to be a little harder than COWW. They actually turned out to be significantly softer. They didn't ring like COWW and the pencils quickly confirmed they were closer to 9 or 10 Brinell to the COWW's 12 Brinell. With that information in hand I adjusted my typical mix to account for the 10 Brinell base stock instead of COWW and successfully created an alloy that tests the same as the finished product I was making with COWW base stock.

[Traffer]

Here is some info that I have gleaned with my own testing added. Once you get used to this it works plenty well enough:

Hold the pencil at a 45 degree angle with the surface you are testing, and push down along the length of the pencil, as if you are trying to shove a knife point into the surface. If you try to push the pencil across the surface as if you are writting on in, you will get a much 'softer' result, because the edge won't be cutting into the surface, it will just be rubbing across the surface.

[HandsOff]

Does anyone know what the higher "H" pencils compare to?
I have some unknown load alloy that tests harder than 4H. Unfortunately, I don't have pencils harder than that to find how hard it really is.

For anyone who's interested, I recently found this page that tells how to make a low cost hardness tester.
Scroll down to the section named "Simple low-cost hardness tester":
http://www.texas-mac.com/Evaluations...s_Testers.html

[Shooter6br]

Used artists set for years Cheap and easy

[6622729]

You're getting most likely into a copper lead alloy that is way outside what we would use for casting. Heck 2H is Brinell 26-28 which is in Monotype territory. 4H is out of sight! I don't think you're going to ID the content with pencils. You'll have to get it shot if you really want to know what's in it. Otherwise, dilute a small sample batch with soft lead down into a hardness that is usable and see how it shoots.

[Traffer]

Here are some practical instructions on hardness testing with pencils with pictures:
Attachment 174723 This is a properly sharpened pencil. 90 Degrees polished with some 1000 grit sandpaper.
Attachment 174724This is the base of a 38 cal slug retrieved from range berm. It is filed down. (note the direction of file marks.) When doing the pencil test go in the direction of the file marks.
.Attachment 174725Push the pencil in the direction that the pencil is pointing. Try to plow a slight groove in the lead. This is the proper angle to use. The amount of force to use will be apparent when you try it. If it cuts in and gouges, the pencil is harder than the alloy. If the pencil slides and the edge crumbles, the alloy is harder than the pencil.
Attachment 174726 This is the "furrow" left by the pencil cutting into the lead. If the lead was harder than the pencil it would not leave this mark. (the same 38 cal slug as the second picture) Notice I went in the same direction as the file marks. If you go against the grain, you can get a false result.
Attachment 174727 Another picture of the pencil cutting the furrows. This is a 38 wad cutter from range berm filed the long way.
You just have to guess the pencil and try to scratch with it. If it cuts in, go to a softer pencil. Repeat until the pencil is too soft to cut the lead. That is the pencil you use for reference. If the first pencil is softer than the lead reverse the process. Go harder until you get to the correct one.
The pencils are from soft to hard High B's are softest to High H's are the hardest. in the mid range it goes 3B, 2B, B, HB, F, H, 2H, 3H, etc.
Here are corresponding harnesses to the Brinell Scale (BHN= Brinell Hardness Number). These numbers are approximate.

Pencil Hardness Reference:
Pencil BHN Common Alloys

7B 4 Pure and Sheet Lead
6B 5 Lead Wire
5B 7-8 40:1 lead/tin, Most 22rf
4B 9 25:1 lead/tin
3B 10 20:1 lead/tin
2B 11-12 wheel weights (WW)
B 13
HB 14-15 Lyman #2 alloy, 1:1 linotype/lead
F 16-18 commercial cast bullets
H 20-22 1:1 linotype/WW, linotype
2H 26-28 Quenched WW, monotype

The set of Pencils can be obtained from Office supply stores like Staples, Office Max, from artist supply stores and from eBay. A set can range from $30 to $5. Mostly depending on the stores mark up. I bought a set of 12 Staedtler Mars Lumograph for about $15. I ended up having to buy 2 extra pencils because the set did not contain a 6B or an F. Make sure that what ever set you buy has ALL of the midrange pencils. (6B, 5B, 4B, 3B, 2B, B, HB, F, H, 2H, 3H) Or you can buy whatever one is missing separately. I just bought another set of 12 Graded Artist pencils. Got them off eBay from the UK. The set was missing HB and is noticeably cheaper but works JUST AS WELL. Price delivered to US was $5.14 US.

[HandsOff]

You're getting most likely into a copper lead alloy that is way outside what we would use for casting. Heck 2H is Brinell 26-28 which is in Monotype territory. 4H is out of sight! I don't think you're going to ID the content with pencils. You'll have to get it shot if you really want to know what's in it. Otherwise, dilute a small sample batch with soft lead down into a hardness that is usable and see how it shoots.

That's what I'll end up doing since I only have ~5 lbs of it, and have no idea what it's composed of (probably throw it in a mix for buckshot). I'm still be curious what it's BHN is though. The 4H dents a groove into the surface, but doesn't actually gouge.

@ Traffer
Thanks, that's one of the most informative post I've come across on pencil prep and use.
I've got the Staedtler Mars Lumograph set; 6B-4H.

[Traffer]

Let us know what you find out. I am curious also.

[Traffer]

I was just testing some of the softest lead I have run into. My Staedtler Mars Lumigraph #6B pencil bounced off of it as it it were harder than 7Bhn or 8Bhn. I didn't believe that. My guess was that it was dead soft or 5bhn. So I went past the softness of the 6B pencil to a 7B pencil (which is supposed to be the next SOFTER in the progression. The 7B scratched the lead no problem. Then I tried the 8B pencil. THAT scratched it no problem. As I suspected this was dead soft pure lead at 5bhn. I went to my other set of pencils by HUE purchased from the UK. That 6B was of the proper hardness. It scratched the lead easily. So, bottom line I bought a set of supposedly the best pencils there are that has a pencil stamped 6B that is actuality softer than 8B. Maybe 9B? Have any of you who use pencils run into this problem? Or if you are planning on using pencils maybe make sure that they indeed do follow the progression and you don't have a oddball hard one in there.

[benellinut]

I was just testing some of the softest lead I have run into. My Staedtler Mars Lumigraph #6B pencil bounced off of it as it it were harder than 7Bhn or 8Bhn. I didn't believe that. My guess was that it was dead soft or 5bhn. So I went past the softness of the 6B pencil to a 7B pencil (which is supposed to be the next SOFTER in the progression. The 7B scratched the lead no problem. Then I tried the 8B pencil. THAT scratched it no problem. As I suspected this was dead soft pure lead at 5bhn. I went to my other set of pencils by HUE purchased from the UK. That 6B was of the proper hardness. It scratched the lead easily. So, bottom line I bought a set of supposedly the best pencils there are that has a pencil stamped 6B that is actuality softer than 8B. Maybe 9B? Have any of you who use pencils run into this problem? Or if you are planning on using pencils maybe make sure that they indeed do follow the progression and you don't have a oddball hard one in there.

Interesting, haven't heard of this from others and haven't seen it with the set I have. Wonder if a pencil or a lead fell out of a bin, got pick up and put in the wrong one at the factory, strange things can happen. Have you tried drawing with them on paper, depending what end of the scale you start from, you should be able to notice they leave progressively lighter or darker lines. For giggles, if you want to try it, sharpen that pencil back a ways, at least beyond the exposed lead and try it again.

BTW, I sharpen/sand the point on mine so it looks like a hot dog cut on a bias, I push the slanted point into the lead. Don't know if that would matter to your results but I just thought of it. Looks something like this

[Traffer]

Interesting. My pencils are different. They are regular wooden pencils with lead in the middle. Have to sharpen the wood off to use them. Yours looks like a better more modern type. I did test the offending pencil on paper. It had a different texture than the one below it and the one above it. More gritty or scratchy. But the darkness of the mark it left was indeed in between the one above it and the one below it. Maybe they used a different binder making it or something. Oh well. I posted a pic earlier of my pencils if you scroll back a ways you can see what they look like and how I sharpen them. Just straight across on a 90 degree angle. That gives me a sharp edge to plow with. The shape of your pencil looks like you have found the ideal way to sharpen that kind. Good work.

[benellinut]

Interesting. My pencils are different. They are regular wooden pencils with lead in the middle. Have to sharpen the wood off to use them. Yours looks like a better more modern type. I did test the offending pencil on paper. It had a different texture than the one below it and the one above it. More gritty or scratchy. But the darkness of the mark it left was indeed in between the one above it and the one below it. Maybe they used a different binder making it or something. Oh well. I posted a pic earlier of my pencils if you scroll back a ways you can see what they look like and how I sharpen them. Just straight across on a 90 degree angle. That gives me a sharp edge to plow with. The shape of your pencil looks like you have found the ideal way to sharpen that kind. Good work.

No, I have the same pencils as you. That's just a pic of another kind I grabbed off the web to show how the point looks after I shape it. I should have made that clear, sorry about the confusion. I don't know if the way I shape them is right or wrong or if it makes much difference, I think the key is constancy on how you test from one batch to another. I do plow that edge, to me it's like using a wood chisel and why "I" do it that way.

[Traffer]

Yes, you can pretty much tell by the way it feels if it is working correctly. I put the pics up to show people who might want to try it but have not yet.

[reed1911]

We use Blick.com for most of our artist needs, they are INEXPENSIVE on everything. Free shipping around 50-60 dollar order. The pencils they have are in three sets, hard ranges from B to 9H, Medium from 6B-4H, soft from 9B to H cost is $9.08 a set of 12. Link for those is below:
http://www.dickblick.com/products/de...FQtufgodSPcIFg

On another note: For those of us who are engineering and/or drafting and/or electronic guys (or those that write very small), they also sell VERY small tip pens for marking on schematics and engineering documents and archiving docs. They have down to 005 size which is 0.2mm, they cost 2-3 dollars and are very well made. To put that size in perspective a regular medium ball point pen is 1.0mm and a fine is 0.7mm. It used to be a chore for me to find 0.5mm pens. With a 005 size 0.2mm I can write 6 lines in the space of a college rule paper evenly spaced, so they are REALLY little. Love 'em brand is Sakura link below:
http://www.dickblick.com/products/sa...ma-micron-pen/

[adam_mac84]

I have read *most* of the pages here... but didn't see anyone commenting on when they test their alloys. Immediately after ingot/casting? After age hardening? 1 week? 2 weeks?