Strain gauge to measure bandsaw tension

How do you make a strain gauge device that measures the strain (change in length) of a metal band by clamping the gauge device onto the metal band. The gauge would be an analog bridge strain gauge that would have to have pads that allow them to be clamped on the metal band, but the material that the gauge device was made of would have to have little effect on the total resistance to elongation of the band, since the band strain vs. force is what is being measured.

I know I could glue a strain gauge on the band itself to do the measurement, but I want to be able to mount and unmount the strain gauge on different bands.

The actual thing I am measuring is the tension in a bandsaw blade. I found I could buy a mechanical strain gauge to do the measurement, but find that I can buy a used strain gauge meter for much less and if I can make a gauge, I will have a strain gauge meter for use in other applications. Also, I believe it could potentially be more accurate also.

Reply to
Eric Anderson
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Could you perhaps mount the strain gauge to something that deflected the blade and "bent" it. Then calculate the the strain. . .somehow. My experience with strain gauges on fuel injector accumulators was a very rigorous long time to set epoxy. Removable/reusable di not appear to be an option.

Good luck, Ed V.

Reply to
EdV

ifferent bands.

In strictly practical terms, simply to set a bandsaw, you would not measure strain (elongation of the steel). You would measure tension (force). Using a strain gauge as a backdoor approach to determine tension would require knowing the coefficient that relates tension to elongation for that particular kind of steel. I forget the terminology. It would also require that you release the tension on the blade, apply the strain gauge, then retighten. Do you really want to go to all that trouble? I value my time more than that. With a tension gauge, just apply the gauge to the taut blade.

Fine Woodworking Magazine (taunton.com) has an article about how to make your own tension gauge. I haven't read it.

Reply to
gearhead

Strain means stretching, and a clamped-on item can stretch if the bandsaw blade stretches OR if the blade simply twists or bows or straightens. Or, if the clamp slips.

Measuring the force on the wheel axle is a better indication of tension, and it's a simple matter of calibrating a spring to do that. If you want to get fancy, consider a hydraulic cylinder in series with the tensioning screw, and measure the hydraulic pressure with a gage or transducer.

Reply to
whit3rd

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