Below you will find answers to our most often asked questions. If you are unable to find your answer, please feel free to contact us.

How often do I need to recalibrate my Skidmore and how do I do it?
We recommend recalibration every year, however frequency of calibration varies by industry and use.  The construction industry typically requires annual calibration due to the critical nature of their work.  Other industries, such as aerospace are even more stringent. To send your unit in, please click here and include the calibration form with your unit.

What's the difference between torque and tension?
Skidmore units were developed for this very question! In the simplest terms, torque is a force applied about an arm.  For example, pulling on a one foot long socket wrench with 50 lbs of force will produce 50 ft/lbs or torque applied at the socket.

Bolt tension is force that wants to stretch the bolt.  Turning the nut in a bolted joint creates this tension.  The resulting tension, or stretching of the bolt, creates the clamp force that keeps the joint together.

Torque and tension are related primarily by friction.  Tests have shown that 90% of the energy used to tighten a bolt is to overcome friction.  Controlling friction is the critical element to successful bolt installation because small variations in friction can cause large changes in bolt tension.

We also make units that are designed to measure torque. These units are designed to test torque wrenches, impact wrenches, etc. In these units, we provide you with the torque number that your tool is producing.

So, how come I can buy a Skidmore calibrator that measures tension and use it to test my impact wrenches?
We developed a method for testing impact wrenches using base mounted versions of our torque/tension calibrators. THESE UNITS DO NOT MEASURE TORQUE. They are designed to provide a method for accurately comparing the output of impact tools. Our test bolt assemblies are manufactured to precision standards.  When used correctly, they present the same joint to the impact wrench for thousands of tests.  Variations in the gage reading in these tests will be due to the tool itself.   Conversion to torque can be made by using a simple calculation. (divide by a factor determined by the bolt size you are using). For more details, see the Tension to Torque Conversion Chart.

My wrench has a reaction arm.  How do I keep from twisting the Skidmore?
When using a wrench with a reaction arm, we strongly recommend purchasing a torque reaction kit that can be mounted to your unit. This will eliminate all of the "side torque" to the unit and make it much easier to use. When calling to order your kit, please know the type of wrench (model, make and arm style) you are using.

I am using really long bolts. Can I just stack washers to make up the difference?
No!  Stacking washers creates a spring.  This will distort your readings and make it difficult for your bolts to pass inspection.  We have two solutions.  First, we make hardened spacer kits to allow you to space out the front of the unit.  These work well when using impact or hand torque wrenches.  When using hydraulic wrenches, or any other tool with a reaction arm, we strongly recommend spacing out of the back of the unit using our spacer bushings.  This will keep the tool close to the face of the Skidmore and reduce the chance of the bolt going through the Skidmore at an angle.

We are using Direct Tension Indicating (DTI) washers.  How does that work with a Skidmore?

When using DTI's you will need to use a Skidmore to "prove" that the DTI is indicating at the correct tension. We have been working closely with all of the manufacturers of these washers and have learned a few tricks of the trade.  For more information about working with DTI's click on this link. DTI White Paper

We are using Tension Control (TC) Bolts.   How does that work with a Skidmore?

When using TC Bolts you will need to use a Skidmore to "prove" that the TC Bolt is "snapping off" at the correct tension. We have worked closely with all of the manufacturers of these bolts and have learned a few tricks of the trade.  For more information about working with TC Bolts click on this link. TC Bolt White Paper

I'm just starting a budget for a unit, what is the approximate cost?
The size of our units varies greatly, so the cost can change.

For testing bolts, the range is approximately as follows: $1,000 to $3,000 for the unit plus $100 to $250 per bolt diameter you will be testing. You may also need to purchase additional plates and bushings for smaller length bolts.

For testing wrenches: the range for the unit is approximately the same and the test bolt assemblies range from $160 to $600 depending on size.

For rotational capacity testing, our units start at $30,000.