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Thread: Easier pencil lead hardness testing

  1. #1
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    Easier pencil lead hardness testing

    This is a simple mod of a pencil sharpener to prepare pencils for lead hardness testing



    Insert pencil and mark the blade where pencil lead and wood meet


    Use a grinder/file/? and remove the cutting edge where the pencil lead is


    Insert pencil and sharpen until pencil lead sticks out past the wood the distance you like (I go a little under 1/4 in)





    Flatten point of pencil lead with sandpaper

  2. #2
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    File bullet/lead flat and smooth
    Hold the pencil at an angle and push across the lead


    If the pencil cuts a trough and leaves a curl of lead, the pencil is harder than the boolit lead "HB" (14-15 BHN)


    If the pencil slides across the lead the pencil is softer than the bullet lead "B" (13 BHN)


    This boolit is between 13 and 14 BHN

    Pencil Hardness Chart
    Last edited by Grmps; 02-19-2018 at 08:25 PM.

  3. #3
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    Good explanation. Looks like it works well.

  4. #4
    Boolit Master MOA's Avatar
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    Grmps, where do you get your pencils at that you use for this method?

  5. #5
    Boolit Master dbosman's Avatar
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    Any artist supply store will have Graphite Pencil Sets.
    Here is just one, online supplier so you can see what you'll be buying.
    https://www.dickblick.com/products/l...te-pencil-set/
    Check thrift shops, when searching for pewter. I lucked out and got a set at a thrift store for $1.99

  6. #6
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    I've been using the pencil hardness test for about 3 years. I got burned once...big. My pencils were out of whack. I kept getting funny readings, even called into question some alloy that I purchased.
    I found out that 2 or 3 of the pencils I had in the 14bhn to 20bhn range seem to have been made differently. The softer ones were darker, but they were harder than some of the lighter shades. In other words. The sequence of hardness between "B" and "H", instead of increasing in hardness from B to H two or three of the pencils actually were SOFTER. Indeed much softer. As I recall a couple on there were softer than 3B. So when I got to where the measurement should have shown like 16bhn or 18bhn, the pencil crumbled. I backed off to softer lead and something like a "H" pencil was showing 10bhn. With 2 or 3 pencils like that, I was very confused. Finally I went back and actually tested the hardness of the Pencils! That is when I found out they did not get sequentially harder even though they got sequentially lighter in shade. Unfortunately I did not write down which ones did what. Since then, I no longer rely on pencils anymore. I got to the point where I can get a relative hardness with my thumbnail...good enough for my work anyway.
    I hope this makes sense to you folks.
    Bottom Line.....TEST YOUR PENCILS before relying on them.
    Other than that the test works well. They use it for materials testing...paint and such.

  7. #7
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    Here is another thread on pencil hardness testing:http://castboolits.gunloads.com/show...s-with-pencils
    Here are some more test parameters:
    Hardness Reference
    Pencil BHN Common Alloys
    7B 4 pure & sheet lead
    6B 5 lead wire
    5B 7-8 40:1 Remington Golden Bullet 22LR
    4B 9 25:1 Many types of 22LR
    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

  8. #8

  9. #9
    Boolit Master dbosman's Avatar
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    I got lucky with my set. I would recommend Staedtler or Faber-Castella as they are a very well known brand. Artists can probably offer some other quality brands.

  10. #10
    Boolit Master Wheelguns 1961's Avatar
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    Very informative. Thanks Grmps!

  11. #11
    Boolit Buddy benellinut's Avatar
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    This is the set I got, it should out last me, doubt you'll find a better price, I paid a couple bucks more a few years ago and thought I got a good deal.
    https://www.amazon.com/STAEDTLER-bre.../dp/B0014E2S0Q
    I printed the chart above and taped it to the underside of the lid and toss one of these nail files in the box, don't tell the wife I stole it from her.

    Click image for larger version. 

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    Be careful what you wish for!

  12. #12
    Boolit Buddy

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    Grmps

    Thank you for this info, and all other posters in the other posts etc.

    I am going to try this lead testing as soon as I get my pencils here,
    I got the Staedtler Mars Lumograph Hard Lead Drafting Art Pencils,
    12 Piece Assortment, 6B thru 4H sizes, for $7.45, including shipping,
    as I need/want the softest lead for casting air rifle pellets.

    Questions for you,
    Has there been any "standardization" as to the angle of the pencil?

    I have read all posts, in several sections and I have found that the angles/info vary's, upon each users method etc.

    What about using a combination square, there is small ones around the 4" range,
    (I have a very small one in the 2" range, some where in the shop), LOL.

    There is a 45* angle built in, I have been testing with the 45* angle on bullets/lead bars, wheel weights etc,
    and it seems to me, (what little I know), that this method would provide a better approximation for the angle.
    that give reasonable readings, for all users etc.

    Would another angle provide better results, ie 20*,30* or 40*, so everyone using this method,
    could kinda standardize their results etc?

    The 45* angle seems too steep for me, with what little info/experience I have etc.

    Just some food for thought......

    Any thoughts or suggestions would be greatly appreciated.........

    Tia,
    Don

  13. #13
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    As far as your angle goes, a little practice and you will find what works for you. The object is to see if the pencil graphite is harder and cuts through the lead. Kind of like setting tools on a lathe. After a while you kind of get the "feel" of the best grind on the tool for cutting. If you have a perfect angle with your pencil and start to plow it through the lead, it will just crumble if it is softer than the lead.

  14. #14
    Boolit Buddy
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    I interesting thread!

  15. #15
    Boolit Buddy

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    Traffer

    Thank you for the info,

    I need/want the softest lead possible for casting air rifle pellets, NOE molds, http://noebulletmolds.com/NV/index.php?cPath=24_573
    and I have some lead here to test, when the pencils get here.

    I was NOT sure of the correct angle to use, when pushing the pencil, to get the best uniform results etc.

    The pencil sharpener, I have here cuts the sharpened angle at around 18* approximately, and I have NOT modified it yet,
    to get the straight section of the lead, past the tapered wood ending, as shown above.

    I can make alum angle ramp (the pencil rests on, when pushing) to get the best repeatable/uniform results,
    and it easier to inform another person, that I used a XYW angle with a WXZ pencil and got these results etc.

    IMHO, it just seems to me, that if standardized angle was used, then the results would be more uniform through out,
    for every ones testing purpose etc.

    I plan on doing some testing of different angles on different leads, just to see the results, just for my own info,
    then I have an better educated SWAG. LOL

    Your thoughts or suggestion.....

    Thank you,
    Don

  16. #16
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    The best way I can come up with to explain it is...It's like using a wood chisel to scrape a thin layer of wood. You can vary it until it works right. It might be a bit different every time but when you have the feel of it you can do it. As far as the pencil lead goes, I do not use a pencil sharpener. I want the whole column of round lead exposed for an eighth of an inch or so and the bottom of the lead finished on a piece of fine sand paper so it it 90 degrees flat. There are pictures of the whole setup on another pencil lead thread here on CB.

  17. #17
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    I went back to the sticky on "Testing Hardness with Pencils". The pictures that I had previously posted are gone. I must have deleted them when my account got full. Here are some pictures of how the pencils are sharpened and how to "plow" a little roll of lead. It it plows up lead the pencil is harder.
    Click image for larger version. 

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  18. #18
    Boolit Man

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    If you want a degree symbol ° , press down the 'ALT' key and type 0176, when you release the ALT key the degree ° symbol appears. Now I know what to use that drafting leads for from my high school mechanical drafting class. Now if I could just find a use for Dietzgen and Post drafting instruments.

  19. #19
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    Quote Originally Posted by Engineer1911 View Post
    If you want a degree symbol ° , press down the 'ALT' key and type 0176, when you release the ALT key the degree ° symbol appears. Now I know what to use that drafting leads for from my high school mechanical drafting class. Now if I could just find a use for Dietzgen and Post drafting instruments.
    Wow I have been wanting to know that for 15 years...THANKS

  20. #20
    Boolit Buddy

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    Engineer 1911

    Thanks for that tip, I put a sticky on this plastic box, so I can remember it.

    Tia,
    Don

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check