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New Invention  
Advances Bolted Joint Design


New DSP invention, ultrasonic invention, & software invention, combine to more reliably measure actual bolt tension, not just bolt torque. Nondestructive testing new invention. New patented technology. See comparison table.

NDT Update says:  
" SureBolt outperformed the one-point bolt gauges on every bolt and every test in reliability and accuracy."

Here is a new patented invention that is useful in these areas:

1.   Bolt failures. What new invention can help mechanical engineers avoid bolt failures? The number one reason, stated by bolting experts, for bolt failures is? Lack of proper pre-load tension. What are some of the factors that cause pre-load tension errors? This affects a bolted joint design, especially the assumptions in structural analysis software. 

2.   Bolt tension, not bolt torque. Tension not torque. You want to put a known amount of tension into your nut and bolt combination, not just a known amount of torque. Your structural analysis often relies on proper pre-load tension. New invention lets you measure pre-load.

3.   Measure Tension errors. How can this new invention measure torque wrench errors?  Do these bolt tension errors matter? These errors often affect a mechanical engineer's structural analysis.

4.   Bolt gage. Your joint's stress analysis can be verified using a bolt gage. What is an ultrasonic bolt gage?  See an animated demonstration of an ultrasonic echo inside of a bolt.  Engineering labs rarely have enough resources to let each engineer learn ultrasonics. Are bolt gages reliable? Are they easy to use? New patented technology has finally made ultrasonic bolt gages reliable and easy to use.

5.   Friction. Mechanical engineers know that bolt and nut friction consume over 80% of the torque measurement.  But, how does the actual tension vary bolt to bolt?  What if you use the same type of bolt? This may affect a mechanical engineer's structural analysis.

6.   Stress, strain & yield. A stress strain curve can be plotted using SureBolt.  Stress strain and yield.  SureBolt's new invention can help a engineer verify his bolted joint design.  Did his bolt reach yield?

7.   Flanges. Flange joints sometimes leak.  Why does the tension in a flange bolt vary so much, bolt to bolt?  How can you tighten each flange bolt to closer tolerances?  How can you use SureBolt on a flange?

8.   SureBolt. How does SureBolt differ from any other ultrasonic bolt gauge? What is the difference between a one-point bolt gage and SureBolt's patented whole echo method? Are the prices similar? (Yes)

9.   Engineers. Some engineers use a strain gauge to measure bolt tension because they know a torque wrench is not directly measuring tension. Yet their structural analysis software may assume a limited amount of error (+- 25%) when calculating bolt tension from bolt torque.

10.  Tension errors. What are some of the tension errors associated with using a torque wrench? Does your stress analysis software let you enter the tension error ranges?

11.  Engineering. This site is a engineering resource for torque versus tension in bolted joints. SureBolt is apatented nondestructive testing - NDT - method of measuring bolt tension. Non destructive testing includes the use of ultrasonics.


SureBolt's Whole Echo patented technology greatly increases reliability by using the whole echo instead of just one point. 

All other bolt gages use just "One Point" (one zero crossing), that leaves you susceptible to peak jumping (20% or more error).  Surebolt is a more reliable bolt gage due to a new patented technology. See comparison table.

Bolt gages have been around for over 20 years. Their "Peak Jumping" problems have kept them from being widely used. When your bolted joint fails or flange leaks, then you find out your bolt gage may have jumped peaks. 

With a lot of training and laboratory testing, NASA has used bolt gages for years. NASA physically takes Polaroid pictures of the echoes before and after tensioning. Then they use their trained human experience to determine if the echo has distorted "too-much". Even after all this, they have to throw away approximately one third of the ET measurements because they are not reliable. When NASA used the SureBolt prototype, no measurements had to be thrown away.

SureBolt gives you a 13.3" TFT, portable PC (Panasonic Toughbook Model 72). The ultrasonic pulser and digitizer are built into the CD ROM and PCMCIA slots. Click here to see the actual SureBolt screens. See the animated DEMO page to see how an ultrasonic bolt gage can measure tension. SureBolt has been used on special high strength titanium bolts to standard "off the shelf" bolts.

For more information, see the main SureBoltTM navigation screen.



SureBolt FLASH Video Why NASA Used Video Download Animated Demo Tutorial On-Line Torque Errors Technical Info Torque Wrench Specifications+ Prices & Compare Services News

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"Echo Time".  See animation below of how to ultrasonically measure the change in bolt tension using echo time.
This animation requires FLASH (version 4 or higher).



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1022 Antelope Trail, Winter Springs, FL 32708, USA

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 No more guessing as to which "one point" is the right point.


The FIRST whole echo method (patented DSP Technique).

SureBolt picture

Built into a 
Panasonic Toughbook

Weather proof keyboard.

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Last Modified: September 27, 2011