SDHT Spring Tester
Super Digital Hand Tester

  • 2, 11, 22, 66, 110, 200 and 750 lbf load capacities
  • Up to 24″ range and 19″ stroke
  • Standard 0.0005″ length resolution

This demo of our Valve Spring Tester shows some of the great capabilities of our robust hand-operated spring tester line.

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Customize & Buy

SDHT Generation 2

The SDHT is our top-of-the-line, benchtop, hand operated spring tester. Available in seven different load capacities, the Super Digital Hand Tester is tuned to the highest precision to excel against your toughest testing requirements.

All Larson Systems spring testers have BUILT-IN DEFLECTION COMPENSATION for accurate readings at all times. Testers without deflection compensation will always have length readings that contain error and this will also limit the benefit of high force resolution.

5 Optional Testing Capabilities That Set the SDHT Apart from Other Spring Testers

  1. Pass Through Testing
  2. Two Point with Rate
  3. Calculated Free Length
  4. Initial Tension
  5. Limit Lights & Full Statistical Analysis

Rugged Construction

Use this tester for compression or extension applications from 2 lbf to 750 lbf. Standard pull lengths of 12” can be increased with optional extended rods to up to 24” to test longer parts. It has very high resolution force and length to test with greater accuracy. The SDHT comes standard with a two-line backlit LED display of force and length with built-in load cell and frame deflection compensation for accurate readings at all times. It has a rugged cast aluminum and steel frame, precision rack and pinion drive with adjustments for wear and convenient hand operation to apply force and adjust length. Precision Guides for increased accuracy are standard on the SDHT and LSI offers powerful, optional tester software features to make testing easy and productive. It includes Micro Length Adjust with built-in stops, standard length lock, rechargeable battery and mechanical overload stops to protect the tester from damage.

 

5 Incredible Testing Capabilities

1. Pass Through Testing


Test up to two preselected force or length points in one spring deflection without stopping. Pass Through Testing will increase operator testing efficiency with the SDHT.

Rather than deflecting the spring and pressing F1 or F2 to capture each individual test point, Pass Through Testing will capture your two preselected force or length test points in one fluid deflection of the spring and display the data on-screen.  Once the test is complete, you can:

 

  • Press SEND to access the data on a connected computer using our SDC (Spring Data Collector) or SSS (Statistical & Spreadsheet Interface Software) software programs, or…
  • Press STORE to save both test points in tester memory, or…
  • Press SEND to print to a connected printer

2. Two Point with Rate

Test two points with spring rate calculation in one deflection of the spring.


2 Point With Rate is a tester software option that allows you to calculate the rate (or spring constant) between two points. To use this feature, press the Test Mode button to enter 2 Point With Rate mode. Set your first test point by using the tester’s force and length readings as a guide and pressing the F1 button. Set the second test point using the same method. When both test points are set the tester automatically calculates and displays the rate as shown. This is all accomplished in just one deflection of the spring!

2 Point with Rate is a tester software feature. A PC is not needed for this software.
Click for Print Samples

3. Calculated Free Length (includes 2 Point with Rate)

Calculate the free length of a compression spring.


Calculated Free Length is a tester software option that allows you to calculate the free length of a compression spring. To use this feature, press the Test Mode button to enter 2 Point with Free Length mode. Set your first test point by using the tester’s force and length readings as a guide and pressing the F1 button. Set the second test point using the same method. When both test points are set the tester automatically calculates and displays the rate and the free length as shown.

Calculated Free Length is a tester software feature. A PC is not needed for this software.

4. Initial Tension (includes 2 Point with Rate)

Calculate the initial tension of an extension spring.


Initial Tension is a tester software option that allows you to calculate the force required to start separating the coils of an extension spring. To use this feature, press the Test Mode button to enter 2 Point with Initial Tension mode. Find the unloaded length of the spring by using the tester’s force and length readings as a guide and pressing the F1 button. Then set the first and second test point using the same method. When both test points have been set, the tester automatically calculates and displays the rate and initial tension as shown.

Initial Tension is a tester software feature. A PC is not needed for this software.

5. Limit Lights & Full Statistical Analysis

Part sorting using bright LED limit lights for good / bad parts and a statistical summary printout that includes a histogram and data run chart.

Limit LightsThis software option lets the user program the limit lights to make sorting reliable and efficient. This option also uses the programmed limits to enable the Mean, Standard Deviation, Range, Range Chart, Histogram, Cp and Cpk statistical printed outputs. Limit Lights and Full Statistics Analysis is a tester software feature. A PC is not needed for this software.

Click here for print samples

Includes Length Deflection Compensation

What is length deflection compensation?
All force/lengh testing devices, regardless of manufacturer, have additional deflection by the load cell and tester frame which occurs as the spring is loaded. If you buy/use a tester without deflection compensation, measurements might include significant length errors.
Spring deflection, also known as spring travel or motion, is the action of a compression spring compressing (being pushed), an extension spring extending (being pulled), or a torsion spring winding (being twisted) when a load is applied or released. This is one characteristic (spring deflection) that is measured by a Larson Systems Spring Tester.

Larson Systems has BUILT-IN Length Deflection Compensation so that the user does not have to calculate and apply length corrections. Most competitors do not have length deflection compensation.

With a Larson Systems product, forget about calculating load cell and frame deflection when testing, we’ve got you covered.

SDC Software Demo

Try our software for “Spring Testing Data at Your Fingertips”. With Larson System’s SDC Software, your spring testing data can be accessed, stored and manipulated as it is generated. Store specifications for different parts, load a set of parameters and clearly see which springs are out of spec using the on-screen graphical representation of the testing results. Save and print results or open the results file in Microsoft Excel. You have complete control of your testing data.

Free Demo

Force Specifications

Load Cell
Capacity		 Standard Resolution
0-20% FS 20-100% FS
2 lb 0.00002 lb 0.0002 lb
907 g 0.01 g 0.1 g
8.9 N 0.0001 N 0.001 N
11 lb 0.0002 lb 0.002 lb
5 kg 0.1 g 1 g
49 N 0.001 N 0.01 N
22 lb 0.0005 lb 0.005 lb
10 kg 0.2 g 2 g
98 N 0.002 N 0.02 N
66 lb 0.001 lb 0.01 lb
30 kg 0.5 g 5 g
294 N 0.005 N 0.05 N
110 lb 0.002 lb 0.02 lb
50 kg 0.001 kg 0.01 kg
489 N 0.01 N 0.1 N
200 lb 0.005 lb 0.05 lb
91 kg 0.002 kg 0.02 kg
890 N 0.02 N 0.2 N
750 lb 0.02 lb 0.2 lb
340 kg 0.01 kg 0.1 kg
3,336 N 0.1 N 1 N
Accuracy = ± Full Scale Resolution x 2

Parts and Accessories

Testers

DescriptionPart Number 
SDHT - Super Digital Hand Tester 2 lb - (2" Platform)050-0000-0043-00Get a Quote
SDHT - Super Digital Hand Tester 11 lb - (2" Platform)050-0000-0044-00Get a Quote
SDHT - Super Digital Hand Tester 22 lb - (2" Platform)050-0000-0087-00Get a Quote
SDHT - Super Digital Hand Tester 66 lb - (2.375" Platform)050-0000-0076-00Get a Quote
SDHT - Super Digital Hand Tester 110 lb - (2.375" Platform)050-0000-0045-00Get a Quote
SDHT - Super Digital Hand Tester 200 lb - (2.375" Platform)050-0000-0077-00Get a Quote
SDHT - Super Digital Hand Tester 750 lb - (2.375" Platform)050-0000-0046-00Get a Quote

Factory Options

DescriptionPart Number 
Quick Release Range Adjust Handles (200 lb Max Load)

Quick Release Range Adjust Handles

Part Number: 025-0000-0412-00

Replace your socket head cap screws with these simple handles for quick and easy range adjusting on your tester. 200 lb maximum load.

025-0000-0412-00Get a Quote
Extended Range Rods to 18"018-0000-1563-01Get a Quote
Extended Range Rods to 24"018-0000-1563-04Get a Quote
Extended Stroke to 19"025-0000-0308-00Get a Quote
Extended Stroke to 19" with 0.312" Ø Thru-Hole025-0000-0308-01Get a Quote
MicroAdjust Wrenchless Stop Assembly025-0000-0676-00Get a Quote

Tester Software Options

DescriptionPart Number 
Pass Through Testing

Pass Through Testing

Part Number: 050-0000-0067-00

Test up to two preselected force or length points in one spring deflection without stopping. Pass Through Testing will increase operator testing efficiency with the SDHT.

Rather than deflecting the spring and pressing F1 or F2 to capture each individual test point, Pass Through Testing will capture your two preselected force or length test points in one fluid deflection of the spring and display the data on-screen. Once the test is complete, you can:

Press SEND to access the data on a connected computer using our SDC (Spring Data Collector) or SSS (Statistical & Spreadsheet Interface Software) software programs, or…
Press STORE to save both test points in tester memory, or…
Press SEND to print to a connected printer

050-0000-0067-00Get a Quote
2 Point with Rate

2 Point with Rate

Part Number: 050-0000-0072-00

2 Point With Rate is a tester software option that allows you to calculate the rate (or spring constant) between two points. To use this feature, press the Test Mode button to enter 2 Point With Rate mode. Set your first test point by using the tester’s force and length readings as a guide and pressing the F1 button. Set the second test point using the same method. When both test points are set the tester automatically calculates and displays the rate as shown. This is all accomplished in just one deflection of the spring! 2 Point with Rate is a tester software feature. A PC is not needed for this software.
Click for print samples!

050-0000-0072-00Get a Quote
Calculated Free Length (includes 2 Point with Rate)

Calculated Free Length

Part Number: 050-1000-0040-00

Calculated Free Length is a tester software option that allows you to calculate the free length of a compression spring. To use this feature, press the Test Mode button to enter 2 Point with Free Length mode. Set your first test point by using the tester’s force and length readings as a guide and pressing the F1 button. Set the second test point using the same method. When both test points are set the tester automatically calculates and displays the rate and the free length as shown. Calculated Free Length is a tester software feature. A PC is not needed for this software.

050-1000-0040-00Get a Quote
Initial Tension (includes 2 Point with Rate)

Initial Tension

Part Number: 050-1000-0041-00

Initial Tension is a tester software option that allows you to calculate the force required to start separating the coils of an extension spring. To use this feature, press the Test Mode button to enter 2 Point with Initial Tension mode. Find the unloaded length of the spring by using the tester’s force and length readings as a guide and pressing the F1 button. Then set the first and second test point using the same method. When both test points have been set, the tester automatically calculates and displays the rate and initial tension as shown. Initial Tension is a tester software feature. A PC is not needed for this software.

050-1000-0041-00Get a Quote
Limit Lights & Full Statistical Analysis

Limit Lights & Full Statistical Analysis

Part Number: 050-1000-0073-00

This software option lets the user program the limit lights to make sorting reliable and efficient. This option also uses the programmed limits to enable the Mean, Standard Deviation, Range, Range Chart, Histogram, Cp and Cpk statistical printed outputs. Limit Lights and Full Statistics Analysis is a tester software feature. A PC is not needed for this software.
Click for print samples!

050-1000-0073-00Get a Quote

Computer Software

DescriptionPart Number 
SSS - Statistical & Spreadsheet Interface Software

Total Spring Inspection
The SSS software can connect to any LSI manual tester, including the DHT and the TST, and virtually any measuring device that can send data via RS232. The SSS can also accept data from the keyboard. By setting up a specific testing method, you can test your springs reliably and repeatedly and generate one comprehensive report.

Click here to view

050-0000-0075-00Get a Quote

Accessories

DescriptionPart Number 
Thru-Rod Support Kit (1/16 to 1/8" Ø x 6")

Thru-Rod Support Kit (1/16 to 1/8″ Ø x 6″)

Part Number: 025-0000-0225-00

Includes rods: 1/16, 3/32 & 1/8″ Ø x 4″ long, accompanying plates with matching holes, as well as upper and lower plates without holes.

025-0000-0225-00Get a Quote
Thru-Rod Accessory Kit (1/16 to 1/4" Ø)025-0000-0424-00Get a Quote
4" Ø Platform / Thru-Rod Support Kit (1/16 to 11/16" Ø ID x 8")

4″ Ø Platform / Thru-Rod Support Kit (1/16 to 11/16″ Ø ID x 8″)

Part Number: 025-0000-0485-00

This kit is more flexible than other thru-rod options and can accommodate larger thru-rods. In addition, springs up to 4″ in diameter can be tested with the over-size platforms.

Includes rods: 1/16″ to 11/16″ x 8″ long, and accompanying plates with matching holes. 4″ Ø plate can double for testing springs with larger diameter.

NOTE: Deflection compensation is calibrated at the center of the platforms. The length error would vary depending on the load and the location of the load. A centered load is always best and will read accurately, to within ± 0.001″ (0.025 mm) of the actual length. A large off-center load near the edge of the extended platform may be off by up to 0.008″ (0.2 mm).

Installation & Use

025-0000-0485-00Get a Quote
Platforms - 4" Ø

Platforms – 4″ Ø

Part Number: 025-0000-0191-00

For testing larger diameter compression parts.

025-0000-0191-00Get a Quote
Set of 2" Spring Platforms (HT Tool Steel, No Hole)025-0000-1597-00Get a Quote
Setup Blocks

Setup Blocks

Part Number: 025-0000-0190-00

For compression / extension length zeroing. 12″ extension zeroing; 10″ compression zeroing.

025-0000-0190-00Get a Quote
Wire Extension Hooks - 2 lb max (0.030" Ø)

Wire Extension Hooks – 2 lb max (0.030″ Ø)

Part Number: 025-0000-0340-05

Medium duty hooks for your extension testing.

025-0000-0340-05Get a Quote
Wire Extension Hooks - 2 lb max (0.050" Ø)

Wire Extension Hooks – 2 lb max (0.050″ Ø)

Part Number: 025-0000-0340-06

Medium duty hooks for your extension testing.

025-0000-0340-06Get a Quote
Extension Spring Swivel Hook Set - 10/66/110 lb

 

Extension Spring Swivel Hook Set – 10/66/110 lb

Part Number: 025-0000-0340-03

Medium duty hooks for your extension testing

Part Number Description
025-0000-0340-05 Wire Extension Hooks – 2 lb max (0.030″ Ø wire)
025-0000-0340-06 Wire Extension Hooks – 2 lb max (0.050″ Ø wire)
025-0000-0340-01 E Wire Extension Hooks – 10 lb max (1/16″ Ø wire)
025-0000-0340-02 E Wire Extension Hooks – 66 lb max (3/32″ Ø wire)
025-0000-0340-00 E Wire Extension Hooks – 110 lb max (1/8″ Ø wire)
025-0000-0340-03 A Wire Extension Hook Set – 10 / 66 / 110 lb max. Includes protective carrying and storage case.
025-0000-0340-03Get a Quote
Pin Extension Hooks

Pin Extension Hooks

Light duty hooks for your extension testing. The above pictures show 025-0000-0250-05 (including the swivel mount).

Part Number Description
025-0000-0250-01 Pin Extension Hooks – 2 lb max (Fixed Mount)
025-0000-0250-02 Pin Extension Hooks – 66 lb max (Fixed Mount)
025-0000-0250-03 Pin Extension Hooks – 110 lb max (Fixed Mount)
025-0000-0250-04 Pin Extension Hooks Set – 2 / 66 / 110 lb max (Fixed Mount) Comes with protective carrying and storage case.
025-0000-0250-05 Pin Extension Hooks Set – 2 / 66 / 110 lb max (Swivel Mount) Comes with protective carrying and storage case.
025-0000-0250-04Get a Quote
Wire Extension Hooks

Wire Extension Hooks

Part Number: 025-0000-0523-00

Medium duty hooks for extension testing. Protective carrying and storage case included with sets.

Part Number Description
025-0000-0340-01 Wire Extension Hooks – 10 lb max (1/16″ Ø wire)
025-0000-0340-02 Wire Extension Hooks – 66 lb max (3/32″ Ø wire)
025-0000-0340-00 Wire Extension Hooks – 110 lb max (1/8″ Ø wire)
025-0000-0340-03 Wire Extension Hook Set – 10 / 66 / 110 lb max. Includes protective carrying and storage case.
025-0000-0514-00 Wire Extension Hooks – 1,000 lb max (5/16″ Ø wire)
025-0000-0523-00 Extension Hook Set – Pin & Swivel – 10 / 66 / 110 / 1,000 lb
025-0000-0523-00Get a Quote
Machined Extension Hooks

Machined Extension Hooks

Part Number: 025-0000-0181-00

Heavy duty hooks for your extension testing.

Part Number Description
025-0000-0183-00 Machined Extension Hooks – 110 lb max
025-0000-0181-00 Machined Extension Hooks – 750 lb max
025-0000-0183-01 Machined Extension Hook Set – 110 / 750 lb max. Includes protective carrying and storage case.
025-0000-0181-00Get a Quote
Wire Crimp Pull Fixture - Upper

Wire Crimp Pull Fixture – Upper

Part Number: 025-0000-0271-00

Test your wire crimp’s integrity with LSI’s wire crimp fixtures. The upper pull fixture features 18 slots ranging from 0.031″ to 0.437″ and can accommodate up to #4 gage wire. Choose between 110 and 1,000 lb lower grip fixtures.

025-0000-0271-00Get a Quote
Wire Crimp Grip Fixture - Lower 110 lb

Wire Crimp Pull Fixture – Lower

Part Number: 025-0000-0274-00

Test your wire crimp’s integrity with LSI’s wire crimp fixtures. The upper pull fixture features 18 slots ranging from 0.031″ to 0.437″ and can accommodate up to #4 gage wire. Choose between 110 and 1,000 lb lower grip fixtures.

025-0000-0274-00Get a Quote
Wire Crimp Grip Fixture - Lower 1,000 lb

Wire Crimp Pull Fixture – Upper

Part Number: 025-0000-0272-00

Test your wire crimp’s integrity with LSI’s wire crimp fixtures. The upper pull fixture features 18 slots ranging from 0.031″ to 0.437″ and can accommodate up to #4 gage wire. Choose between 110 and 1,000 lb lower grip fixtures.

025-0000-0272-00Get a Quote
Smooth Jaw Wire Chucks - 100 lb

Wire Chucks

Part Number: 025-0000-0193-00

For extension wire breakage testing: accepts 0.020″ to 0.312″ Ø wire.

025-0000-0193-00Get a Quote
Serrated Jaw Wire Chucks - 200 lb

Wire Chucks

Part Number: 025-0000-0193-01

For extension wire breakage testing: accepts 0.020″ to 0.312″ Ø wire.

025-0000-0193-01Get a Quote
Smooth Jaw Wire Chucks - 400 lb

Wire Chucks

Part Number: 025-0000-0193-02

For extension wire breakage testing: accepts 0.020″ to 0.312″ Ø wire.

025-0000-0193-02Get a Quote
Air Vibration Damping Table

Air Vibration Damping Table

Part Number: 025-0000-0288-00

The Air Vibration Damping Table allows you to make very accurate force measurements in normal industrial environments that have floor or building transmitted vibrations. These vibrations may be induced by industrial equipment, local car, truck or rail traffic and in some cases by people walking by. The Air Vibration Damping Table reduces the magnitude of vibration by 10 to 100 times, making it possible to accurately measure forces at very light loads in environments that would otherwise be impossible. The table should be considered for applications with forces less than 10 lb and is highly recommended for applications with forces less than 2 lb.

Air Vibration Damping Table Setup:

  1. Mount the CDHT, DHT or SDHT onto the table using the four included 1/4-20 x 3/4” bolts.
  2. Turn the three front air valves (clockwise) to the “off” position.
  3. Connect a pneumatic air line.
  4. Turn air valves (counter-clockwise) to pressurize each mount so that the table is not resting directly on the three mounts, and the weight on the table is supported (80 PSI maximum).
  5. Place a leveling instrument on the table and adjust the air pressure equally until the table is level.
025-0000-0288-00Get a Quote
Vibration Damping Pad

Vibration Damping Pad

Part Number: 025-0000-0226-00

Foam Vibration Damping Pad

025-0000-0226-00Get a Quote
5/16-18 M to 10-32 M/F Thread Adapter

Thread Adapters

Part Number: 018-0000-1718-00

Use differently threaded attachments with your Larson tester.

018-0000-1718-00Get a Quote
5/16-18 M to M6 M/F Thread Adapter

Thread Adapters

Part Number: 018-0000-1718-01

Use differently threaded attachments with your Larson tester.

018-0000-1718-01Get a Quote
5/16-18 M to M4 M/F Thread Adapter

Thread Adapters

Part Number: 018-0000-1718-02

Use differently threaded attachments with your Larson tester.

018-0000-1718-02Get a Quote
Dust Cover (Standard 12" Range Rods)

Dust Cover

Part Number: 059-1000-0004-00

059-1000-0004-00Get a Quote
Dust Cover (18" Range Rods)

Dust Cover

Part Number: 059-1000-0012-00

059-1000-0012-00Get a Quote
TUL - Twist Under Load

Twist Under Load

Part Number: 050-0000-0099-00

Graduated Markers
The Twist Under Load has indicating marks that will measure the amount of twist in any given spring.

Capacity
From 10 to 2,000 lbs and up to 4″ Ø.

Captivated Ball Bearings
With lubricated ball bearings, this unit will rotate smoothly and with very light force.

Universal Mounting (excluding the Flash 11 & Flash 24)
Will mount to any Larson tester, or any tester with 5/16-18 mounting holes.

050-0000-0099-00Get a Quote
Small Parts Catcher for 2" diameter platforms018-0000-4228-00Get a Quote
Rubber Mounting Foot Upgrade025-0000-1310-00View Product
Solid Height (Coil Bind) Protector - 2.375" 018-0000-4358-01View Product
Solid Height (Coil Bind) Protector - 2" 018-0000-4358-01View Product

Power Supplies

DescriptionPart Number 
Power Supply - USA (115 VAC)025-1000-0396-00Get a Quote
Power Supply - International (100-240 VAC 50-60 Hz)025-1000-0396-04Get a Quote