Need Help Choosing an Electric Torque Screwdriver?

Knowing the difference between the ES, ED and EA torque screwdrivers is essential when choosing the correct screwdriver for an application. 

Lever Start (ES Series)

The ES series are direct plug in, lever start screwdrivers with a slip/cushion type clutch.  The lever start option allows the operator to engage the screwdriver by applying a slight amount of pressure on the trigger lever.  When the torque setting is reached, the slip/cushion clutch slips until the operator releases the lever.  This feels like a slight release of pressure on the bit of the screwdriver to the operator.  The torque setting is set by adjusting the Stepless Torque Adjuster at the bottom of the screwdriver.  (See Figure 1)

ES Lever Start Selection Guide Chart: This selection chart will help guide you in choosing the correct ES torque screwdriver for your assembly application. Screw sizes for both metric and standard screws are found on the left side of the chart. Across the top are the ES screwdrivers that we offer. Simply match your screw size to the ES screwdriver.

Push to Start (ED Series)

The ED Series direct plug-in electric torque screwdrivers offer a few benefits over the ES series.  The ED series has a Full Auto Shut-Off clutch that completely shuts the screwdriver off once the torque setting is reached.  This ensures that the fastener is not damaged by the screwdriver's bit.

Secondly, the ED series has a Push-to-Start clutch.  With the Push-to-Start clutch, the screwdriver starts to turn once the operator applies a slight force to the screwdriver's bit. 

The ED series is fully automated, turning off once the torque setting is reached.  The torque setting is set by adjusting the Stepless Torque Adjuster at the tip of the screwdriver. (See ED Series Screwdriver, Figure 2).

ED Push to Start Selection Guide Chart: This selection chart will help guide you in choosing the correct ED torque screwdriver for your assembly application. Screw sizes for both metric and standard screws are found on the left side of the chart. Across the top are the ED screwdrivers that we offer. Simply match your screw size to the ED screwdriver.

DC Electric Screwdrivers (EA Series)

The EA serie are DC electric screwdrivers with an external power supply.  The power supply plugs into either an AC112V or 220V source and converts to a DC 20 or 30 V depending on the DC screwdriver.  These screwdrivers are lighter than the ED series screwdriver and have more options when it comes to the screwdriver's RPM. 

The EA series screwdrivers come with Electrostatic Discharge (ESD) protection housing.   ESD protective housing is a must when working with sensitive electronic parts such as circuit boards.

The EA series have a Full Auto Shut-Off clutch that completely shuts the screwdriver off once the torque setting is reached.  This ensures that the fastener is not damaged by the screwdriver's bit. 

EA series come in both Lever and Push-to-Start motors.  With the Push-to-Start motor, the screwdriver starts to turn when the operator applies a slight force to the screwdriver's bit.  With the lever start option, the operator engages the screwdriver by applying a slight amount of pressure on the trigger lever.  The EA series are fully automated turning on with a slight force to the screwdriver's bit or trigger lever and turning off once the torque setting is reached.  The torque setting is set by adjusting the Stepless Torque Adjuster at the tip of the screwdriver (see figures 3 and 4).

Here are some simple rules when choosing an electric torque screwdriver.

1. Only choose an ES series screwdriver when you are sure the the fastener being used is made of a material that will not damage once the slip clutch engages.
2. Use the ED series screwdriver when it meets your application's RPM and torque ranges.
3. If the weight of the screwdriver is important to your applications, the EA series are the lightest.
4. If your application involves working on sensitive electronic pieces, the EA series has ESD protective housing.
5. The EA series offers more RPM options.  The RPM of the screwdriver is important to applications that have fasteners or host materials that require slow turning cycles.  For example, if the fastener turns too fast, it may heat up and snap or damage the host material.

Express Assembly Products
199 Rt 101 • P.O. Box 369 • Amherst, NH 03031
TOLL FREE 1-866-863-2302 • (603) 424-5590 • Fax: (603) 424-5595
email: info@expressassembly.com