•     Polish the desired surface and bring it to the smoothness of the appropriate surface (obtained with at least 200 grade sandpaper).
•     Clean the place of hardness measurement from substances such as oil and dust.
•     Choose the minimum distance between the hardness measurement locations at least twice the diameter of the hardness measurement effect.
•     Do not measure the hardness twice on the same point.
•     Place the metal forehead of the hardness tester completely perpendicular to the surface and do the hardness measurement without hand shaking

This message appears for two reasons:
1. If the number obtained in hardness measurement is outside the defined range, this message is given. For the type of metals other than LS and HS, this limit is more. The table of quantities and metals in the manual shows the measurement range, and the items outside of it include the None message.
For example, for cast iron hardened up to 60HRC, you should select LS as the metal type, and if GG metal type is selected, the None message will appear after the test.
2. Penetration of contaminants such as shavings and oil into the launcher also causes disruption in the hardness measurement and the appearance of the None message. You must open the metal cap of the launcher and clean the inside of the launcher tube with a cleaning brush and with the help of dry cleaning spray (salty contact) or gasoline or... For better washing, you can remove the projectile after opening the metal cap by pressing the test button and do the washing (note that you must hold the projectile with your hand or a soft object immediately after pressing the test button to avoid missing prevent it from happening).

In the following cases, the hardness is shown lower than the actual value:

•         The thickness of the part is less than the allowed amount or the coupling is inappropriate
•         The weight of the part is less than the allowed weight or the couple is not suitable
•         Improper polishing and surface smoothness
•         Failure to choose the correct type of metal
•         Hand tremors during hardness testing

1. Open the plastic nut of the device.
2. Take the launcher out of the device frame.
3. Open the steel cover of the launcher.
4. On the side of the brass cover, open the 2 four-sided screws to remove the flakes.
5. Take out the spring and frame of the magnet and projectile.
6. Clean the inside of the projectile tube well using the brush in the device bag and contact spray or gasoline or alcohol. Move the brush back and forth as well as in a circular manner in the tube to remove the dirt in front of the electronic eye well, then repair the inside of the tube with air, repeat this process several times.
7. Close the steel cap of the device and insert the projectile into the tube from the bottom of the tube so that the tip of the diamond is on the side of the steel cap.
8. Place the magnet frame inside the brass cover so that the glued side is up.
9. Place the spring on the magnet frame and close the bottom cover with the square screw.
10. Turn the launcher so that the projectile is in place.
11. It is better to do this after every test day.

This hardness tester measures the hardness of the metal through the protrusion phenomenon according to the Leeb method, and through the table of equality of hardness quantities (according to the standards), the measured hardness is converted to Brinell (HB), Vickers (HV), Rockwell. Rockwell C) HRC- C) and Rockwell Rockwell B) HRB - B) displays. In the LEEB method, the projectile (Impact Device) (equivalent to the indenter in static methods) is thrown to the surface of the metal and is repelled by the metal. The ratio of the velocity of the projectile is related to the hardness of the metal, and this relationship is introduced with the LEEB unit.