DIY spoke tension meter calibrating device.

Here, I explain the function and importance of a tension meter, and show the construction of a calibration device

[@MsBarbarian1]

Very meticulous! People like you are rare! I really enjoyed the video.

[@canyoneagle]

Great job! I also use a Wheelsmith tensionometer, which is now more than 15 years old. You've given me the inspiration to roll up my sleeves and get fabbing! See you back on BF!

[@scottthomson120]

Pretty sweet build! Great video, thanks for sharing. I just purchased a new old stock Wheelsmith tensiometer...Calibration sheet year 1997...My first thought was whether the calibration had changed over time, just sitting unused.

[@mozzmann]

Funny how you tend to find stuff on YT that tells ya everything you need to know. I needed to make a tension meter for a specific project I was involved in and applying tension to cables was involved. I built a tension meter and your calibration tool, and later found I had built version of the Fanatyk tensiometer without realising it. Many local kids bring bikes for me to both build and true wheels so I am now building my own Wheel Fanatyk type meter but with an adjustable spring.

[@mizzorian]

Great video. There are people out there who made a calibration tool themselves using very expensive devices which I do not understand why when the idea is simple. I was thinking something even simpler than this in the video. How about a spoke fixed at one end and mass put on at the other end (known mass- I was thinking of dumbells), then calibrate your tension meter according to that mass and type of spoke.

[@kurtvogler6583]

OK, I finished my calibration tool. I decided to make mine with wood. I had some spare wood laying around and it worked just fine. It does flex a little bit; but it stays static to obtain accurate readings. Even so, I may add a crossbar in the middle to reduce this effect. I used an old hub to hold the spoke elbow on the bottom. Two 1/2" holes in the wood allowed me to sandwich the hub in the jig upon final assembly. This worked out fine except when measuring bladed spokes! I realize that one cannot hold the tension meter just anywhere when measuring bladed spokes and the jig got in the way. So I just fixed the hub in place so the spoke being measured was to the side of the jig. Anyone considering using a hub should think about this. Let me say this: a Sapim bladed spoke with nominal cross section of 0.92mm has a VERY different deflection than a similar, but round, spoke (obviously)! Now I KNOW what 110kg is! Again, a big thanks to Dan for posting this and sharing his idea with the world!

[@2wagondragon]

Thank you for watching, and for the comment.

[@rv8-m948]

Great Video Thanks! Has given me some ideas. One would be to use aluminum and rivets/bolts as I am not a welder.

[@2wagondragon]

Thanks Bill.I can point you to the vendor for the scale if you decide to do it.

[@eavalos3]

I've just made mine. I ordered the same scale from Amazon. Thanks!!!

[@2wagondragon]

Great stuff. Thanks for commenting.

[@kurtvogler6583]

Thank you SO much for the great video! I've been searching high and low for calibration charts for different spokes for my Ice Toolz tension meter (which is suspiciously similar to the Sapim non-digital meter). Kinda a pain in the butt searching high and low for all the permutations out there. Your calibration tool makes all this superfluous! I like it because it serves TWO functions: calibrate the meter and determine deflection values for a given spoke. Since there are myriad spokes out there, from straight gauge stainless to butted, ovalized aluminum, there's just no way to get deflection values for every spoke and every meter being used. I just found a post on a UK builder's site that quoted a Sapim rep saying basically, "You can't assume deflections of a DT spoke will match our Sapim deflections. Send us your DT tension meter for calibration." I'll suggest a couple of ideas to simplify your tool: 1) Suspend scale between ceiling and work bench (assuming bench is bolted down and you set a solid eye-bolt in a ceiling joist). If bench isn't stout enough, just set an eye bolt in the shop floor. Easy-peasy! 2) Thread sample spoke through a dummy hub (which is held to the other side with another dummy spoke) instead of having to cut off the elbow and thread the other end. Thanks again for your video. Can't wait to get my tool up and functioning!

[@kurtvogler6583]

Thanks for the Ebay link! I was about to purchase one on Amazon for almost $60; your link has one for $32!

[@2wagondragon]

Thanks for the comments and good luck with your build. I have updated the design a bit. I posted a video of the update.

[@wheeleyguy]

+Steve Smith Hey Steve....check out Bill Mould's videos----He has one that feature's a display of the Sapim calibration chart...It's very clear.....Check It Out....

[@dudeonbike800]

Thanks for pointing me to Bill's videos. He has a lot of good information. Be aware, however, that the Sapim chart is not a calibration chart, but a deflection value chart - FOR THE INTENDED TENSION METER. This is a valuable resource, but only for a person using a CALIBRATED Sapim spoke tension meter. It's worthless for any other tension meter (or a Sapim meter that's lost its accuracy) because different meters use different geometry and spring tensions, so the deflection they measure equates to different kgf tension values. In fact, Bill shows his own tension calibration tool near the end of the video, which makes all the deflection charts he has moot. And I would assume that the Sapim chart only shows THEIR spokes and most certainly not, say, a Mavic Ksyrium aluminum bladed spoke. And this is what makes Dan's tool so useful - it allows the user to determine exactly what spoke deflections are created by ANY meter on ANY spoke. It also obviates the need to ever recalibrate one's tension meter. Why have it match a pre-determined deflection value when I know the current deflection value(s) the meter is reading? It's simply an academic endeavor that serves no purpose. If my tension meter read 3.44 at 100 kgf last year, but now reads 3.30 at 100 kgf TODAY, who cares, as long as I'm reaching my desired end tension? (And assuming the tool consistently reads 3.30 at 100 kgf during the wheel build, I'm set.) 100 kgf is 100 kgf no matter where you are. Once you put 100 kgf on a spoke, you simply "reverse-engineer" your meter's readings. So simple and elegant.

[@smithraymond09029]

Negligible reading change over 9 years of use tells me this tension meter is basically calibration free over it's lifetime assuming no abuse. Saves me the need to build this calibration device at all.

[@2wagondragon]

If you are comfortable making that assessment from a sample size of one, then sure. Thing is, I'm encountering aero spokes that are not precisely described on the original calibration sheet, and I'd rather not have to guess at it.

[@kurtvogler6583]

I just built a wheel with Sapim bladed SS spokes with nominal cross section of 0.92mm. Deflection at 110 kg measured 2.51 mm on my tension meter, which was nowhere near the deflection of the closest spoke I've used before, a 1.5mm butted DT, at 3.25mm deflection. Sure, one can guess, but if you're doing that, it defeats the purpose of using a tension meter to achieve ideal spoke tensions. (Although still useful to achieve uniform tensions throughout the wheel.) This tool solves this confounding issue for wheel builders encountering the myriad spoke designs out there. Add to this the fact that the high-end consumer is utilizing carbon rims. A wheel builder will want to know exact tensions when building carbon wheels to achieve good builds and as a way to reduce liability. If a spoke pulls through, destroying a carbon rim ($$$), I want to be sure I've put spoke tensions within manufacturer specs.

[@2wagondragon]

Steve Smith I've been building a lot with Sapim cxray bladed spokes and carbon rims, 6 wheels just today. Without the calibration tool, I would be way over tensioning the spokes, no doubt about it. The meter readings you get from a bladed spoke are way different than what you get from round ones.

[@Triestini]

I’ve just bought a used second hand Park Tool spoke tension meter and was thinking of going along to a couple of my local bike shops and calibrating it against their tension meters.

[@reptilezs]

thanks. i plan on using it for checking my tension meter. i have been using cx ray bladed spokes and dt revolution super butted spokes lately and do not trust the conversion table that park has.

[@alexr5819]

Thanks for the video! Have you tried checking the calibration of a Park Tool TM-1? I have not been impressed with Park Tool's manufacturing tolerances and have had other items from them arrive out of calibration so I'm interested to hear how this tool holds up.

[@2wagondragon]

Thank you. be sure to show us the result. As I told Bill, if you want the name for the scale vendor, let me know. It's a really neat little unit.

[@klausdunayev7078]

How do you fit a standard "J bend" spoke in that jig, considering both retention plates are mounted parallel to each other?

[@klausdunayev7078]

Huh, I saw your other video where you said you had to cut and thread the J bend spoke. And obviously saw your upgraded version. Nice!

[@voodoobreak3864]

hi dan, and thanks, working in france with a dt tensio analog, passionate by precise work, that's a real problem to "re calibrate" the dt (they don't want to give the steel piece they use to calibrate) have to send back to switzerland and pay almost the price of the scale...using musson chart for sapim, greame for campa, but also've to work on other brands, and thickness measure is not accurate enough....long time i want to do this kind of calibrating device....your video finished to convice me ;) .... scale ordered, frame in progress soon... xkyuze my broken english....- greetingz from france loicQ vodooz wheels -

[@2wagondragon]

Thanks for your comment. I'm sure it will be the answer to your problem.

[@voodoobreak3864]

certainly a part of yes :) .... also speaking with mr kralyevski for reliable tensiometer..... frame is done !! waiting for scale and working on "plates" and tension system.....

[@Stelios.Posantzis]

Would it be possible to use the calibration device (suitably modified) to grade the scale on a tuning meter and then use the tuning meter to determine the tension of the spokes?

[@2wagondragon]

Don't forget that the length of the spoke affects the pitch as well as the tension and cross section. I believe pitch is useful only to compare tension balance, not so much for measuring actual tension.

[@Stelios.Posantzis]

@@2wagondragon True - also material would affect mass/density and the length would depend on the kind of rim, nipple and hub flange. Oh well, there's far too many variations for it to be practical when one is dealing with all kinds of bicycles. Perhaps it would be interesting to have at a wheel building factory/facility, where wheels of the same kind are being churned out continuously.

[@itsumohitori]

Great idea, however shouldn't you have to fix the tensed spoke somehow before taking the reading, as i imagine taking the reading with the ''moving'' scales being a part of the system will also inflict further tension on the spoke/system, any thoughts?

[@2wagondragon]

Well, your comment shows you're thinking, but it's better in my mind to keep the scale as part of the dynamic as the variance can be monitored. In practice, I have found no more than 1% variance when taking a reading, ie, at 100 kgf, no more than 1kgf variance. Fixing the spoke in place could easily cause far more variance with no way to monitor it. That's my theory anyway, and I'm sticking to it. :)

[@itsumohitori]

Was just thinking that myself, that due to complexity it might be not worth the hassle. Thanks for the reply and best regards

[@kurtvogler6583]

This scale is not spring-loaded. It does not move when loads are placed on it; I used calipers and measured the two metal ends with zero weight and with 100kg and it did not change in length. In other words, the scale does not "sag" when loads are put on it, so original spoke tension does not drop when the tension meter is applied. Thus, no need to "fix" the spoke; it's already fixed in place between the base and the scale. Measuring spoke tension does indeed increase spoke tension temporarily. This happens when one measures deflection on a wheel or a jig. It doesn't matter, as the spoke returns to original tension once the tension meter is removed. When you use a tension meter, you are measuring the original spoke tension through deflection. You are not deflecting a deflected spoke, so to say. If you put a SECOND tension meter on a spoke, you'd be measuring the sum of the original spoke tension and that imparted by the FIRST tension meter. It's irrelevant.

[@KarlosEPM]

Remarkable. Thanks for this.

[@reptilezs]

hi this looks great and i am about to build it. i plan on using a wooden frame. where did you get the scale? i see them on ebay for about 50 bucks

[@ironman1518.]

Thank you! Excellent presentation!! I have one of the "Wheelsmith" tension meters but NOT the chart. HOW/Where can i get a copy of the chart please? Thank you in advance.

[@2wagondragon]

The chart is unique to each instrument and is made after calibration of the tool. Ric Hjertberg who along with his brother founded Wheelsmith still provides calibration services for this tool. He can be contacted at www.wheelfanatyk.com/

[@ironman1518.]

Thank you had so hoped I could find the chart online to save some money.

[@philip614]

hello...what is the source of the digital scales?

[@cotswoldseeker5609]

Hello Dan, this is an awesome video! Thanks for sharing :) Can I just ask, would 25mm square box section with 1.2mm wall thickness be strong enough for making the frame of this awesome looking calibration device? I would love to make one up for myself here in the UK. Many thanks.

[@2wagondragon]

1.2mm is only 1/64th" thinner that what I used (1/16") so it should absolutely be fine as long as you can weld it without blowing holes in it.

[@cotswoldseeker5609]

@@2wagondragon Thanks Dan, you're a star! I will get cracking with it soon. All the best from the UK :)

[@fabr1c1om]

hello, where can I find a metal platform to place the balance and spoke?

[@atexnik]

Great calibration device!!!

[@fxFRA27]

This is great! But all the problem, know, is to find a well calibrated scale...

[@SkibidiWaPaPaPaPa]

Now how do you calibrate the digital scale?? lol, ok well its a great video and a very clever way to verify that your tension meter is still accurate :) thanks for the video

[@dudeonbike800]

Buy a second scale, or third, to confirm values, if you're THAT worried about it! Actually, the BEST way to confirm accuracy is to simply pick a known weight and suspend that on the scale to confirm scale accuracy. You could also just get a 110 kg weight and suspend that on your spoke (or scale) to confirm everything's accurate. Kind of a pain, but not out of the realm of possibility.

[@cmscott]

You don't have to calibrate the scale...it "Tares to 0" when you turn it on...aka = self-calibration. Provided there is no load (which is why he raised the nut) when it is turned on, it self-calibrates.

[@cmscott]

@@kevinchrist1658, great idea!

[@dudeonbike800]

@@cmscott actually, "tare" just sets it to zero, but this does NOT calibrate the scale. The only way to know the scale is accurate is to either trust the manufacturer and their QA/QC, understand the scale's acceptable error, and/or put a known weight or tension on it to confirm. As posted above, hang 100 kg of weight on it and confirm the scale reads 100kg. (Or 100 lb., whichever is easier.)

[@jean-jacquesgargowitsch5740]

Vous est il possible de donner les dimensions pour le cadre à faire SVP Cordialement.

[@fnx-wheels]

sorry for my bad english.. where can i find a dynamometer like that? thanks

[@rulfi1950]

Nice job Dan! Thanks for share!

[@2wagondragon]

I got it on ebay from the vendor I linked to in the description. I recommend both the product and the seller.

[@wm0davis]

Excellent video. I may do one of those to check mine.

[@wm0davis]

I would be interested in your source of that scale. Thanks

[@wonkylommiter6364]

Fantastic idea, good thinking!

[@Marc_B.]

I would've zero'd the scale with the top U-bolt weight applied, but nothing below, I think. Maybe the it's insignificant...

[@xvdifug]

I like your work bench, Thanks for the vid.

[@2wagondragon]

Not a dynamometer, but there is a link to the ebay vendor for the scale in the video description.

[@paulsartre8498]

Awesome work, thanks sir!

[@tomekkot6695]

Can you give me the dimensions of the frame that you built? Thanks! Excelent work! :)

[@2wagondragon]

The outside dimensions are 26" high by 8" wide

[@tomek_kot]

Dan Burkhart Thank you. Can you give me also wall thickness of the metal profile?

[@2wagondragon]

Tomek Kot I used 1":x1" square tubing with 1/16" wall thickness. Non of these dimensions are critical. You could use angle iron for that matter.

[@tomek_kot]

Thank you! My machine buliding in progress :) :)

[@heemlo649]

You made a mistake when using your device. The scale should read 0 with the weight of the top u-bolt on it, but you lifted that u-bolt up when zeroing the scale. Doing it the way you did it, if the u-bolt weighed 50 kilograms, then the scale would read 50 with no tension on the spoke. Also, this device assumes that the scale is calibrated, so I'm not sure what the point is. And do you have a problem with mig welders lol? One more thing, how would I measure the tension on an aero spoke (non-circular cross section)?

[@2wagondragon]

+Heem Point taken about the weight of the u bolt,but the weight of this assembly is insignificant. It works perfectly with aero spokes. I work with them a lot, in fact the vast majority of the wheels I've been building recently use Sapim CXRays. The calibration chart that was supplied with the tension meter showed calibration for spokes that were only an approximation of the cross section of these spokes. If I went by the calibration chart for aero spokes, I would be way off.

[@heemlo649]

Dan Burkhart Ok thanks, I had actually just looked up the chart you are talking about and noticed it had aero spokes on there. Helpful to know it isn't necessarily that accurate for them. I'm sure the weight of the u-bolt is insignificant, but it is gratifying to point out people's mistakes XD

[@wheeleyguy]

+Dan Burkhart When mounted vertically, the load is less than .05 of a Kilogram;in other words,the difference is VERY minor and you can use the tare feature....when mounted horizontally,the difference is ZERO...No load from the source...Your calibrator is VERY accurate....

[@fnx-wheels]

ok, i found it! thanks!

[@iva4856]

The audio is low.

[@akatsukihoshino8037]

cool~

[@fnx-wheels]

my english is too bad to understand in the video description.. sorry.