Larson Systems Inc.
Manufacturing Expert Spring Testing Solutions Since 1979
Built to order.
This demo of our Valve Spring Tester shows some of the great capabilities of our robust hand-operated spring tester line.
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
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.
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:
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
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.
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.
Part sorting using bright LED limit lights for good / bad parts and a statistical summary printout that includes a histogram and data run chart.
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.
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.
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.
| 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 | ||
| Description | Part Number | |
|---|---|---|
| SDHT - Super Digital Hand Tester 2 lb - (2" Platform) | 050-0000-0043-00 | Get a Quote |
| SDHT - Super Digital Hand Tester 11 lb - (2" Platform) | 050-0000-0044-00 | Get a Quote |
| SDHT - Super Digital Hand Tester 22 lb - (2" Platform) | 050-0000-0087-00 | Get a Quote |
| SDHT - Super Digital Hand Tester 66 lb - (2.375" Platform) | 050-0000-0076-00 | Get a Quote |
| SDHT - Super Digital Hand Tester 110 lb - (2.375" Platform) | 050-0000-0045-00 | Get a Quote |
| SDHT - Super Digital Hand Tester 200 lb - (2.375" Platform) | 050-0000-0077-00 | Get a Quote |
| SDHT - Super Digital Hand Tester 750 lb - (2.375" Platform) | 050-0000-0046-00 | Get a Quote |
| Description | Part Number | |
|---|---|---|
Quick Release Range Adjust Handles (200 lb Max Load)
Quick Release Range Adjust HandlesPart 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. | 025-0000-0412-00 | Get a Quote |
| Extended Range Rods to 18" | 018-0000-1563-01 | Get a Quote |
| Extended Range Rods to 24" | 018-0000-1563-04 | Get a Quote |
| Extended Stroke to 19" | 025-0000-0308-00 | Get a Quote |
| Extended Stroke to 19" with 0.312" Ø Thru-Hole | 025-0000-0308-01 | Get a Quote |
| MicroAdjust Wrenchless Stop Assembly | 025-0000-0676-00 | Get a Quote |
| Description | Part Number | |
|---|---|---|
Pass Through Testing
Pass Through TestingPart 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… | 050-0000-0067-00 | Get a Quote |
2 Point with Rate
2 Point with RatePart 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. | 050-0000-0072-00 | Get a Quote |
Calculated Free Length (includes 2 Point with Rate)
Calculated Free LengthPart 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. | 050-1000-0040-00 | Get a Quote |
Initial Tension (includes 2 Point with Rate)
Initial TensionPart 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. | 050-1000-0041-00 | Get a Quote |
Limit Lights & Full Statistical Analysis
Limit Lights & Full Statistical AnalysisPart 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. | 050-1000-0073-00 | Get a Quote |
| Description | Part Number | |
|---|---|---|
| SSS - Statistical & Spreadsheet Interface Software Total Spring Inspection | 050-0000-0075-00 | Get a Quote |
| Description | Part Number | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Thru-Rod Support Kit (1/16 to 1/8" Ø x 4")
Thru-Rod Support Kit (1/16 to 1/8″ Ø x 4″)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. | 025-0000-0225-00 | Get a Quote | ||||||||||||||
| Thru-Rod Accessory Kit (1/16 to 1/4" Ø) | 025-0000-0424-00 | Get 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 
| 025-0000-0485-00 | Get a Quote | ||||||||||||||
Platforms - 4" Ø
Platforms – 4″ ØPart Number: 025-0000-0191-00 For testing larger diameter compression parts. | 025-0000-0191-00 | Get a Quote | ||||||||||||||
| Set of 2" Spring Platforms (HT Tool Steel, No Hole) | 025-0000-1597-00 | Get a Quote | ||||||||||||||
Setup Blocks
Setup BlocksPart Number: 025-0000-0190-00 For compression / extension length zeroing. 12″ extension zeroing; 10″ compression zeroing. | 025-0000-0190-00 | Get 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. | 025-0000-0340-05 | Get 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. | 025-0000-0340-06 | Get a Quote | ||||||||||||||
| Extension Spring Swivel Hook Set - 10/66/110 lb
Extension Spring Swivel Hook Set – 10/66/110 lbPart Number: 025-0000-0340-03 Medium duty hooks for your extension testing
| 025-0000-0340-03 | Get a Quote | ||||||||||||||
Pin Extension Hooks
Pin Extension HooksLight duty hooks for your extension testing. The above pictures show 025-0000-0250-05 (including the swivel mount).
| 025-0000-0250-04 | Get a Quote | ||||||||||||||
Wire Extension Hooks
Wire Extension HooksPart Number: 025-0000-0523-00 Medium duty hooks for extension testing. Protective carrying and storage case included with sets.
| 025-0000-0523-00 | Get a Quote | ||||||||||||||
Machined Extension Hooks
Machined Extension HooksPart Number: 025-0000-0181-00 Heavy duty hooks for your extension testing.
| 025-0000-0181-00 | Get a Quote | ||||||||||||||
Wire Crimp Pull Fixture - Upper
Wire Crimp Pull Fixture – UpperPart 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. | 025-0000-0271-00 | Get a Quote | ||||||||||||||
Wire Crimp Grip Fixture - Lower 110 lb
Wire Crimp Pull Fixture – LowerPart 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. | 025-0000-0274-00 | Get a Quote | ||||||||||||||
Wire Crimp Grip Fixture - Lower 1,000 lb
Wire Crimp Pull Fixture – UpperPart 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. | 025-0000-0272-00 | Get a Quote | ||||||||||||||
Smooth Jaw Wire Chucks - 100 lb
Wire ChucksPart Number: 025-0000-0193-00 For extension wire breakage testing: accepts 0.020″ to 0.312″ Ø wire. | 025-0000-0193-00 | Get a Quote | ||||||||||||||
Serrated Jaw Wire Chucks - 200 lb
Wire ChucksPart Number: 025-0000-0193-01 For extension wire breakage testing: accepts 0.020″ to 0.312″ Ø wire. | 025-0000-0193-01 | Get a Quote | ||||||||||||||
Smooth Jaw Wire Chucks - 400 lb
Wire ChucksPart Number: 025-0000-0193-02 For extension wire breakage testing: accepts 0.020″ to 0.312″ Ø wire. | 025-0000-0193-02 | Get a Quote | ||||||||||||||
Air Vibration Damping Table
Air Vibration Damping TablePart 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:
| 025-0000-0288-00 | Get a Quote | ||||||||||||||
Vibration Damping Pad
Vibration Damping PadPart Number: 025-0000-0226-00 Foam Vibration Damping Pad | 025-0000-0226-00 | Get a Quote | ||||||||||||||
5/16-18 M to 10-32 M/F Thread Adapter
Thread AdaptersPart Number: 018-0000-1718-00 Use differently threaded attachments with your Larson tester. | 018-0000-1718-00 | Get a Quote | ||||||||||||||
5/16-18 M to M6 M/F Thread Adapter
Thread AdaptersPart Number: 018-0000-1718-01 Use differently threaded attachments with your Larson tester. | 018-0000-1718-01 | Get a Quote | ||||||||||||||
5/16-18 M to M4 M/F Thread Adapter
Thread AdaptersPart Number: 018-0000-1718-02 Use differently threaded attachments with your Larson tester. | 018-0000-1718-02 | Get a Quote | ||||||||||||||
Dust Cover (Standard 12" Range Rods)
Dust CoverPart Number: 059-1000-0004-00 | 059-1000-0004-00 | Get a Quote | ||||||||||||||
Dust Cover (18" Range Rods)
Dust CoverPart Number: 059-1000-0012-00 | 059-1000-0012-00 | Get a Quote | ||||||||||||||
TUL - Twist Under Load
Twist Under LoadPart Number: 050-0000-0099-00 Graduated Markers Capacity Captivated Ball Bearings Universal Mounting (excluding the Flash 11 & Flash 24) | 050-0000-0099-00 | Get a Quote | ||||||||||||||
| Small Parts Catcher for 2" diameter platforms | 018-0000-4228-00 | Get a Quote | ||||||||||||||
| Rubber Mounting Foot Upgrade | 025-0000-1310-00 | View Product | ||||||||||||||
| Solid Height (Coil Bind) Protector - 2.375" | 018-0000-4358-01 | View Product | ||||||||||||||
| Solid Height (Coil Bind) Protector - 2" | 018-0000-4358-01 | View Product |
| Description | Part Number | |
|---|---|---|
| Power Supply - USA (115 VAC) | 025-1000-0396-00 | Get a Quote |
| Power Supply - International (100-240 VAC 50-60 Hz) | 025-1000-0396-04 | Get a Quote |
