PROFESSIONAL
Digital Hardness Tester for Metals (Rebound Type)

Instruction Manual
Model No. LHT-400plus

LEEB HARDNESS TESTER

Thank you for purchasing the Niigata Seiki Leeb-Type Hardness Tester.
This digital instrument measures the hardness of (non-magnetized) metals: steel, cast steel, tool steel, stainless steel, heat
resistant steel, standard (gray) cast iron, ductile (nodular cast) iron, cast aluminum alloys, brass, bronze, and copper. Hardness ismeasured by impacting the surface of the sample with a test probe and measuring the rebound velocity.
● For safe and proper use of this product, please read this

instruction manual before use and follow the procedures
described. Please keep manual where it is accessible to user
for future reference.
● Keep this manual with the instrument if transferred or leased
toa third party.
● For inquiries about this product, please contact dealer orNiigata Seiki at the address listed on the following page.

SAFETY NOTIFICATIONSIn this manual,
indicates RISK OF PERSONAL INJURY
OR PROPERTY DAMAGE if not followed. The
symbolindicates something which is PROHIBITED, and thesymbol indicates REQUIRED step or necessary condition.

■ PART IDENTIFICATION & FUNCTION[Main Unit]⑤ Port Cover⑥ Measure Button④ USB Port⑦ Handle③ LCD Display② Measuring
Ring⑩ Up Button⑨ Down Button① Probe⑧ Power Button[Accessories]⑪ USB Cable ·················· Connects for charging Main
Unit and transferring data.
⑫ Cleaning Brush ··········· For cleaning inside of MainUnit.
⑬ Measuring Ring (sml.) ··· Replaceable tip for use intight places.
⑭ AC Adapter⑭ AC Adapter ················· Charges Main Unit via the
USB Cable.
⑮ Calibration Block ········ Test Block of specified hardness
for checking, and calibrating
unit before each test.
⑮ Calibration ● Storage Case ·············· Storage case for Main Unit
and accessories.
Block● Instruction Manual ······ This user guide.

⑪ ＵＳＢ Cable⑫ Cleaning
Brush⑬ Measuring Ring (sml.)● Case● Manual[Measurement Screen]
Ⓛ Ⓑ Ⓚ

Ⓐ
Ⓜ

Ⓒ

414

H HL :
MAX: 419
M I N: 411
AVG: 414

AUTO HL: 3 3
D ST&CAST
ST■Standard
Display

Ⓙ

A001
075%

Ⓘ Ⓗ

① Probe ·························· Impactor which strikes surface
during measurement.
② Measuring Ring ·········· Pressed to surface during
measurement.
③ LCD Display ··············· For display of measurements
and settings.
④ USB Port ···················· Connects to included USB cablefor charging and data output.
⑤ Port Cover ··················· Cover for USB Port. Pleasekeep closed when not in use.
⑥ Measure Button ··········· Press to release Probe andtrigger a measurement.
⑦ Handle ························· Move down to position Probefor measurement.
⑧ Power Button ·············· Power ON/OFF, and menu
select button.
⑨ Up Button ···················· Button to select a setting, andto control display size.
⑩ Down Button ················ Button to select a setting, andto delete last measurement.

Ⓓ
Ⓔ
Ⓕ
Ⓖ

ⒷⓀ Ⓒ
AUTO HLⒶ

H HL :

419■Large Readout
DisplayⒶ Scaled t / AverageⒷ ScaleⒸ MeasurementⒹ MaximumⒺ MinimumⒻ AverageⒼ Record NumberⒽ Battery Charge LevelⒾ No Measurements / TotalⒿ Material SettingⓀ High・Low Limit Exceeded（Ｈ） （Ｌ）Ⓛ Memory Auto / OffⓂ Probe Type

Press the Up Button
to toggle
between Standard and Large readout

SAFETY PRECAUTIONS

Please Observe

Always follow the procedures specified below in order to prevent harm to yourself or others, and to prevent damage to property.
■ Content marked as follows indicates risk of injury or
damage if not followed.

■ These symbols mark content that must be observed.

risk of personal injury or
W AR NING Indicatesproperty damage if not followed.

Denotes a prohibition– You MUST NOT do

Denotes a requirement –You MUST do

C AUT I ON
Read the manual and follow all instructions.

・Use of product other than as described in the manual may
cause accident.

Use only for measuring hardness.

・Use for any purpose other than measuring may damage orwear the instrument. Improper use may also cause accident.

Use in an environment which meets the following
conditions:● Keep away from direct sunlight● Keep in dry location protected from rain and water.
● Protected from use by children and unauthorized people.
・Use in location contrary to the above may cause poor accuracy,
damage to the product, or may result in accident or injury.

Handle With Care.

・Do not drop or subject to shock, do not place under heavy
objects. Damage may cause failure or poor accuracy.

Preparation of Test Surface
The workpiece and measured surface must meet the following conditions.
① Mass: 5 kg or more

※For workpiece weighing between 2 and 5 kg, or for thin and easily
deformed parts, place on a surface plate or stable surface of morethan 5kg.
※For workpiece weighing less than 2kg, secure it to a surface plateof more than 5kg using a coupling agent, such as petroleum jelly,with a tight fit to stabilize.

Not for use on on materials which are easily fractured, or
which will be damaged by the dents created during tests.

・This instrument measures hardness by impacting a probe, witha hardness of HLD 1600, against the test surface. Please note:
after testing, some small dents will remain on workpiece.

Do not use on magnetized material or in presence ofmagnetic fields.

・ Hardness is measured based on rebound speed of the Impact
Probe. If magnetic field is present, the rebound speed may beaffected and a precise measurement is not possible.

Do not dry­fire instrument.

・If test is performed without test surface under probe, theinstrument may be damaged and affect accuracy.

Do not Modify or disassemble beyond the procedures・
described in this manual.

・It may damage product or affect accuracy. For service,please contact distributor or place of purchase.

Accuracy Confirmation ・ Calibration

Instrument accuracy will be affected by shock or Probe wear.
Please check accuracy and calibrate before each use using
the supplied Calibration Block.
① Confirm the hardness written on Calibration Block

The hardness of the calibration master is marked on the block surface.
※For D type Probe . . . HLD value, For DL type Probe . . . HLDL value.

② Surface Roughness: Ra 2μm or less※If surface is rougher than Ra 2μm, please polish to meet specification.

③ Radius of Curvature: greater than 30mm
④ Test site must be 5mm or greater from edge of surface.
⑤ Surface Temperature: 80°
C or less⑥ For testing surface hardness, a hardened surface thickness:
0.8mm or greater⑦ Not Magnetized※Be sure to demagnetize if there is any residual magnetism.

⑧ Bare (unpainted) Surface※ If sample is painted, remove any paint or coating before test.

⑨ Not easily fractured, or damaged by the surface indents
resulting from the test

※This instrument measures hardness by impacting a probe, with ahardness of HLD 1600, against the test surface. Please note: after
testing, some small dents will remain on workpiece.

Charging⑮ Calibration Block

Block hardness② Measure the Calibration Block hardness

Use the "Hardness Test Procedure" on the following page to test
the hardness.
● Material = Steel ● Scale = HLD/HLDL ● No. of Meas. = 5※Make sure the Calibration Block surface is clean before measurements.
※Take the measurements in a spot free of marks from previous
measurements.

③ Error Correction※If the measured hardness from step ② is within ±19HL of thehardness from step ①, then the accuracy is confirmed within theguaranteed range and the instrument is ready to use.

※If the measured hardness from step ② is NOT within ±19HL of thehardness from step ①, then the calibration must be adjusted. Enterthe measurement error In the "Setup Menu" → "6. Calibration" asshown in the following page.

① Connect with the provided USB Cable

Connect to the AC Adapter using the included USB cable.

② Plug in the AC adapter

Plug the AC adapter into the power mains (100V AC).

④ USB Port

⑭ AC Adapter

Connect

The Main Unit contains a rechargeable battery. Whenpower level drops below 20%, please charge as follows.
Main Unit⑪ USB Cable

ct

ne

n
Co

USB PortPower ON／OFF
The power will turn on and the Measurement Screen will display on the LCD.
● Power ON ··········· Press the Power Button.
● Power OFF ········ From the Measurement Screen, press and hold the Power Button
for 3 seconds. Power and LCD will turn off.

Hardness Test Procedure※Because workpiece hardness my not be uniform, measurements should betaken from multiple locations on the surface of the workpiece for averaging.

３

Follow the steps below for a basic hardness test.

Specify the workpiece material and desired scale units in the "Setup Menu"→ "3. Material & Scale" After entering the settings, select"1. Measurement" to return to the Measurement Screen.

③ Press the Measuring Ring against the surface.

Make sure the workpiece and test spot meet the conditions listed in the section"Preparation of Test Surface", and press the Measuring Ring onto the surface.
※Make sure there are no scratches or marks from previous measurements.

⑦ Handle④ Push down on the Handle, and then pull it back up. (Figure 1)

Workpiece

Push down on the Handle to charge the internal probe for the test,
then lift the Handle to bring it into position for the test.
※Be careful not to push down on the Measure Button when pushingdown on the Handle.
※Make sure you hold the Handle secure while bringing it up to the top.
If the Handle slips, it may return with a shock and cause damage.

⑤ Press the Measure Button. (Figure 2)

With the Measuring Ring held firm to the surface, press the Measure
Button. The Probe will release and impact the surface. Hardness
will be calculated from the rebound velocity.

※Be careful not to push down on the Handle when pressing the
Measure Button, it will cause inaccurate readings.

: 3 3
D ST&CAST
ST

A001
075%

Minimum
Average（Fig.３）【Automatic Angle Compensation】 WorkThe instrument automaticallysenses the measurement angle
and applies a correction factor to
the reading. Measurement canbe made freely over 360° range.
Please
make
sure
the
Measuring Ring is always
pressed firm against the surface
when taking a measurement.

piece

re

The average value, maximum reading, and minimum reading aredisplayed on the LCD display.

H HL :
MAX: 419
M I N: 411
AVG: 414su⑦ The measurements are displayed. (Figure 3)

Maximum

414

AUTO HL

Average
Value（Fig.２）ea

Repeat the required number of times specified in the "Setup Menu"→ "Average times" for calculating an averaged reading.

（Fig.１）M⑥ Repeat the measurement in steps ④~⑤ .

⑥ Measure
ButtonReturn to top② Set the material and measurement units.

２

to turn on the power.

１ Push down

Press the Power Button

Press① Turn the power ON.

② Meas.
Ring

Setup Menu
When power is ON, pressing the Power Button
will display the Setup Menu screen. Within the Setup Menu, the Up and Down
buttons
are used to select items and to change values, and the power button
is used to enter the selection.

1. Measurement ····· Return to the Measurement Screen.
2. Average times ···· Change the number of measurements averaged for each reading. You can select 2-8 measurements.
3. Material & scale ··· Specify the workpiece material, and set the measurement scale. Back Page: Meas. Range Listing for Each Material, Scale
When specifying the material and scale, options are shown, so select as required.

4. Tolerance ········ To set up tolerance function. Press Up Button

to change the value, and Down Button"H" or "L" will appear on the display for readings above or below the set limits.

5. Memory ·········Control the storage of measured data.

1. Memory ··············· Yes - Will save the data in the destination specified in the File setting.
No - Measurement data will not be saved.
2. File Setting ·········· Specify the storage destination for the measurements.
Ten groups, A to J, can be stored with 200 Measurement sets each.
3. Delete single ······· Delete data from the specified group.
4. Delete ··············· Clear the measurement data stored in the Main Unit.

6. Calibration ······· Correct the measurement by entering the error value determined in the accuracy check from the "Calibration" section
on the previous page.

7. Auto shutdown ···· Select the time for Auto power off feature – 1min. , 2min., 5 min, or disabled.
8. Contrast ········· Adjust the contrast of the display.
9. Impact device ·····Set parameters to match the type of probe Back Page: Installing DL-Type Probe (sold separately)
10. Languages ······ Select from Japanese / English.
11. Default ········· Restore all settings to factory default.

Measurement Data Output① Connect the Main Unit to the computer

Computer USB Port

Please connect the USB Port of the Main Unit to the computer's USB Port using the
USB Cable and turn on the power. The Display will show "Connected between
instrument and PC"and the computer will show a CD drive icon.

Co② Open the CD drive icon on the computer, and go to the DATA folder.

ectConnect

The data is stored as text (.txt) files labeled A∼J, and you can open the desired file toview.
The file contents are listed below:

File No
ImpactMaterial
No
1〜８
AVG
MAX
MIN

⑪ USB Cablenn④ USB Port

File Number
Probe type: D/DL
The material type set in the "Material & scale" setting
The scale set in the "Material & scale" setting
Meas. data. The number will correspond to the "Average times" setting
The average value for the 1~8 measurements as specified
The maximum value for the 1~8 measurements as specified
The minimum value for the 1~8 measurements as specified

Main
Unit
Connect to PC※ Please do not delete any of the folders. All folders besides DATA are system folders.

Changing The Measuring Ring, Cleaning※ Before cleaning, or replacing the Measuring Ring,
make sure the power is turned OFF.

The Measuring Ring can be exchanged with a small one if required to fit in tight locations.
Also, the ring can be removed to for periodic cleaning inside of the mechanism.

Loosen① Press the Measure Button.

Release the probe from charged position.

② Turn the Measuring Ring to remove it from the Main Unit (Figure 4) and take out the Probe.

③ Cleaning.

Using the supplied brush, clean the inside of the main unit as well as the Probe toremove any dust or dirt.

④ Replace the Probe and reattach the Measuring Ring to the Main Unit.

② Measuring
Ring（Fig.４）TightenThreads② Measuring Ring

Insert the Probe in the direction shown in the drawing. (Figure 5)Screw the Measuring
Ring back on to the main body.

Installing DL-Type Probe (sold separately)
Measurement can be made in narrow spaces, such as the bottom groove of a large
gear, by replacing the Probe with the DL-type Probe available for the Hardness Tester. （Fig.５）① Press the Measure Button.

① ProbeInsertMeasurement guide

Release the Probe from charged position.

② Turn the Measuring Ring to remove it from the Main Unit (Figure 4)
and take out the (D­type) Probe.
③ Insert the DL­type Probe as shown in the drawing and attach themeasurement guide. (Figure 6)④ Change "Setup Menu → "9. Impact device" from "D" to "DL".

（Fig.６）

Meas. Range Listing by Material, Scale■ D -Type Probe

Material
Scale HLD
σb
HRC
HRB
HB
HV
HS
1. Steel & cast st. 300-878 10.0-68.0 38.4-109.0 80-739 80-940 30.2-98.0 373-1994
300-840 20.4-67.1
80-898−−
2. CW tool steel−−
300-800 19.6-62.4 46.5-101.7 85-655 85-802−−
3. Stainless steel−−
4. Grey cast iron360-650−−
90-334−−−
5. Nodular cast iron 400-660−−
131-387−−−
6. Cast aluminium 170-570−
23.8- 84.6 19-164−−−
7. Brass
200-550−
13.5- 95.3 40-173−−−
8. Bronzes
300-700−−
60-290−200-69045-315−−
9. Copper−−−■ DL- Type Probe

Material
Scale HLDL
HRC
HRB
HB
560-950 21.0-68.0 37.0-100 81-646
1. Seel & cast st.
2. CW too steel
560-943−−
20-187HS

31 - 97−HVσb

80 -950 373-1994
21 - 191−

DL-Type Probe

InsertSPECIFICATIONS● Accuracy: within ±19HL● Operating Temperature: 0∼+40°C● Weight: Main unit … 90g● Data Storage: Max. 2,000 sets
● Auto Power Off: 1, 2, 5 min., or disabled● Continuous use time:~16 hr on full charge

Maintenance / Storage
Remove any dust or grime with adry cloth.
Any contamination entering inside theMain Unit will prevent smooth
operation of the Probe.

Store in a cool, dry, and dark
location in the provided case.
Keep out of direct sunlight and moisture,and please keep secure fromunauthorized personnel.

Niigata seiki Co., Ltd.
5-3-14, Tsukanome, Sanjo, Niigata, Japan, 955-0055
Tel. : +81-256-33-5522 Fax. : +81-256-33-5518

MAIL intl.sales@niigataseiki.co.jp
URL http://www.niigataseiki.co.jp

I404-K

2004