[MTB maintenance] Spoke tension meter calibration tool - How to make your own conversion diagram

I have finally upgraded my home-made spoke tension calibration tool. To use my Chinese garbage spoke tension meter in my wheel building projects, I have made up a tension conversion diagram for it. This video will show you how to do it.
For those who have long waited for this video, here is it for you all. I apologise for a long delay :)

[@pyt22fr11]

Hello, this is the kind of work and experiments that I LOVE. Serious work, congratulations.

[@MindDesignFactory]

Glad you like it :) Thanks for watching!

[@rolandberendonck3900]

Well done! and this setup seems to be working just fine. What is the exact type number of your crane scale?

[@MindDesignFactory]

The exact model name of my crane scale is MNCS-M.

[@rolandberendonck3900]

@@MindDesignFactory Great 👍 Thank you 😊

[@philip614]

hello.... please explain the need/function of the "tension master"?? Also , i guess the accuracy of the crane scales could need checking with hanging known weights [ eg 25kg, 50kg 100kg etc , so as to construct a calibration graph]

[@MindDesignFactory]

Hi, the tension master is a reference object that "is considered" to have a certain tension constantly under this and that specified conditions. It serves as a simplified calibration tool instead of the proper calibration with a calibration device and real spokes. You can verify in a very simple way if your tension meter works properly using the tension master. If you run a pro bike shop, you need to calibrate the master itself periodically of course. Speaking of the accuracy of crane scales, those unexpensive crane scales like mine should not be considered to have the accuracy adequate for any serious or professional situations. These scales are not capable of showing the accurate values when you keep placing high loads on them for a longer period of time. So even if you calibrate them with reference weights, they are not suitable for professional level tension meter calibration tool in the first place. If you want to calibrate your tension meter in a more serious manner, you must use an industrial level "load cells" or "force gauges" with a very sturdy cage of steel. But it will cost loads of money. A very amateur wheel builder like me never needs that kind of accuracy. I am going to upgrade my calibration tool, but the current one will do just fine for any personal wheel building projects. Thanks for watching and your feedback.

[@philip614]

@@MindDesignFactory thankyou for the superb answer, & explaining the "tension master". I am currenty putting together a tensiometer calibration device , inspired by your design, for amateur wheel building .

[@MindDesignFactory]

Great! I highly recommend using a really robust steel cage, frame or base construction. Mine is made of a piece of construction wood block and a couple of steel angles, but it takes some time for the scale readings to stabilise especially when the spoke tension goes over 100kgf. I am planning to make a new upgraded version using a load cell, an electric indicator and a robust steel base. Also I think it is better to fix the end of the scale, not the end of the spoke, and to pull the spoke instead of the scale to measure the tension. Good luck with your calibration tool! PS. A low-cost professional tension meter calibration tool is available at the cost of about 400USD. And a digitized industrial level force gauge without a stand or cage costs over 900USD. There are many cheap Chinese alternatives available of course, which are more than enough for us, I think : )

[@philip614]

@@MindDesignFactory thankyou. Yes , the wood base is sure to be the least suitable component….. so maybe i will use se box-section steel for ?mark2 version

[@MindDesignFactory]

I used the construction wood block half for fun, half seriously. It actually stands for over 200kg load easily without being bent. The problem is rather with those steel angles that are slightly bent as the load increases. The steel box beam is definitely a good base material. I wish you luck!

[@simonstockwell4792]

Do you have calibration data for 2.0 1.8 2.0 spokes?

[@MindDesignFactory]

I will make conversion charts for DT Swiss Competition 2.0-1.8-2.0 and Champion 2.0 hopefully within this month. I have already got those spokes to be measured on my calibration tool. As you may already know, the conversion chart of DT Swiss 2.0-1.8-2.0 double butted spokes can't be applied to the same type of spokes from another brand. Also, my conversion chart is improbably of any help. Because your tension meter is not set up just like mine.

[@simonstockwell4792]

@@MindDesignFactory Thanks.