I am toying with the idea of getting a hardness tester and am looking for input. I am sure there is some kind of direct correlation between price and equipment. How much does one have to spend to get a tester that is accurate enough for knife makers? Are the Enco testers ($679 imports) worth the investment? I see that many offer ball penetrators, some offer diamond tips and others offer both. Which type of tip is generally preferred?
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Hardness testers
- Thread starter Fox
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- Apr 21, 2004
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- 64
Knifemaker Ray Rogers built his own. You might visit his site, www.rayrogers.com, for more info. - Jim
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- Sep 9, 2003
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Fox, that is the unit that I work with. It has been pretty consistant in its readings over the years, you will just need to get an accurate test block to zero it in, since the ones provided are not entirely realiable. With a lot of that import stuff you can get one that is really lousy or one that is really good, the quality control seems to have a wider range.
In that little wooden box, shown with the tester, is an asortments of tables, anvils and other goodies, including both a ball penetrator and a pointed one for "C" scale, as well as another for "A" scale (which I have never used). I have mostly used the "c" scale over the years but the "b" scale has came in quite handy for doing research and testing on annealed materials. Oh- and that price is about $300 less thatn I paid for the same unit :grumpy:
In that little wooden box, shown with the tester, is an asortments of tables, anvils and other goodies, including both a ball penetrator and a pointed one for "C" scale, as well as another for "A" scale (which I have never used). I have mostly used the "c" scale over the years but the "b" scale has came in quite handy for doing research and testing on annealed materials. Oh- and that price is about $300 less thatn I paid for the same unit :grumpy:
Thank you for the excellent feedback. It turns out that Grizzly sells the same unit and since they have a showroom here I can save on shipping and get it locally for the same price.
Everyone - where is the best place to get test blocks and what ranges are needed? I have a couple of old scrap ATS-34 blades heat treated by Paul Bos. As I recall, he gets ATS-34 to about Rc 60? Can these be used for test block material?
Kevin - is the unit user adjustable based upon the readings from the test blocks?
Everyone - where is the best place to get test blocks and what ranges are needed? I have a couple of old scrap ATS-34 blades heat treated by Paul Bos. As I recall, he gets ATS-34 to about Rc 60? Can these be used for test block material?
Kevin - is the unit user adjustable based upon the readings from the test blocks?
Sando
Knife Maker
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- Jul 4, 2002
- Messages
- 1,148
Fox,
Test blocks have a very smooth finish (a rough finish will give varying results depending on whether or not the diamond starts on a ridge or or whatever). Also they are supposed to be a consistent hardness over the entire surface. Also the thickness needs to be consistent - well I should say the top and bottom need to be parallel - so there's no movement as the pressure is applied.
That said, if all you want is to double check your tester from day to day, put a mirror finish on the tang of one of those Bos blades and you can use that. However, if you really want to know the HRC of your blades to the 1/2 point, then a good quality test block is necessary.
I have a D2 blade I use to check the tester before each use. It's been measured at 59.5. If that's the reading I get, I proceed. But occasionally (weather changes, haven't used in a while, ...) I use the fancy testblock. But those test blocks are so $$ I don't want to use it up.
Steve
Test blocks have a very smooth finish (a rough finish will give varying results depending on whether or not the diamond starts on a ridge or or whatever). Also they are supposed to be a consistent hardness over the entire surface. Also the thickness needs to be consistent - well I should say the top and bottom need to be parallel - so there's no movement as the pressure is applied.
That said, if all you want is to double check your tester from day to day, put a mirror finish on the tang of one of those Bos blades and you can use that. However, if you really want to know the HRC of your blades to the 1/2 point, then a good quality test block is necessary.
I have a D2 blade I use to check the tester before each use. It's been measured at 59.5. If that's the reading I get, I proceed. But occasionally (weather changes, haven't used in a while, ...) I use the fancy testblock. But those test blocks are so $$ I don't want to use it up.
Steve
- Joined
- Sep 9, 2003
- Messages
- 2,361
Sando has good advice here. Test blocks are not cheap, but they are necessarry if you really want it to be HRC58 when it is telling you HRC58, but a good answer is to calibrate with your good test block and then use the ones provided with the machine to check it any other time. Speaking of calibrating, yes you can adjust things on that unit, lift the top cover off and you will see a small square weight, with a set screw that slides along the main lever arm. Moving it forward will decrease the minor load, backwards will increase it. If the minor load is lessened, there will be a greater discrepency between that and the major load, which will lower your hardness reading, and vice versa. I feel confident that my unit is fairly consistant because I can change very little, if at all, with this adjuster.
If you find a good source for test blocks let me know, I have been calibrating mine with the with the cooperation Tim Zowada, who has a good test block and good accurate tester.
Keep the anvil and base srew well oiled and make sure that you discrad the first two or three readings that you take on that day, as it will take a couple of loadings to sqeeze the oil and anything that may have settled from the base and it threads. If you ever hear that really high pitched crunchy sound as the major load is applied, ignore that reading and start over. Crushing dust or grit in a test completely messes it up
If you find a good source for test blocks let me know, I have been calibrating mine with the with the cooperation Tim Zowada, who has a good test block and good accurate tester.
Keep the anvil and base srew well oiled and make sure that you discrad the first two or three readings that you take on that day, as it will take a couple of loadings to sqeeze the oil and anything that may have settled from the base and it threads. If you ever hear that really high pitched crunchy sound as the major load is applied, ignore that reading and start over. Crushing dust or grit in a test completely messes it up
Thanks for the great information, gents. Looks like I get to go to Grizzly and make a new addition to the shop! 
Kevin, per RL, I did a quick search and there are several Wilson test blocks on eBay right now. It looks like new Wilson blocks from Instron run about $70 each, for a single Rc value, as a price comparison.
Kevin, per RL, I did a quick search and there are several Wilson test blocks on eBay right now. It looks like new Wilson blocks from Instron run about $70 each, for a single Rc value, as a price comparison.
You can hold out and keep checking Ebay. I have bought a couple from there for about 20 bucks per. They are used. One important consideration is to look for how used it is. The more diamond indentions the less use is left for you. I recently directed another knife maker to one on Ebay that had a 'buy it now' price of $7. It was a HRc 64 test block. It turned out to only have had about a dozen indentions on it. That was a real find and very worth him buying. New test blocks can run hundreds of dollars.
Look for a block or two that is close to the hardness you will be working (around the HRc 60 range). There are lots of blocks sold on Ebay that are of different scales. So, be careful to note that the block you are interested in is for the C scale (HRc).
Steves's advise about smoothness is excellent. I have noticed a marked difference in how a blade tests depending on the smoothness of the test surface.
RL
Look for a block or two that is close to the hardness you will be working (around the HRc 60 range). There are lots of blocks sold on Ebay that are of different scales. So, be careful to note that the block you are interested in is for the C scale (HRc).
Steves's advise about smoothness is excellent. I have noticed a marked difference in how a blade tests depending on the smoothness of the test surface.
RL
Is there any reason that test blocks cannot be put on the surface grinder and refinished? It would be easy to take out the divots and have a fresh block. I am assuming that they are fully hardened and as long as they are not over heated you should end up with a new block. Or, am I missing something?
Test blocks are considered such because of precision. Applying grinding heat, machining stress, or loosing the calibrated surface hardness comprimisies the reference piece. You will note that even the opposite side of test blocks are not recommended for testing.
RL
RL