Spoke tension meter calibration
 

Spoke tension meters calibration

http://www.wheelpro.co.kr/files/atta...alibration.jpg

I had a problem that can't believe the FSA reading as I use it. It show me too high reading, so I needed a tension meter calibration fixture and made it. it's able to calibrate any tension gauges and use any spokes. it's great to check tension meters if there is correct(accruate) or not.

The calibration fixture I designed and manufactured uses high quality loadcell and digital indicator. It's very high accruate to calibrate spoke tension gauges and some test(stretch, tensile....)

http://www.wheelpro.co.kr/25696

please feel free to contact me if you have a problem on your tension meter or to calibrate.

This looks a lot like the calibration fixture we made at Trek back in the early 80s for the wheel building operation, except we didn't have a digital readout.

Like you, we noticed that spoke tension meters seldom gave realistic values and required frequent re-calibration to remain consistent.

I love smart people!

So is this an ad for the product? an ad for the service of calibration? Or both? Translation engines ***k.

It a ad for the product.

Go ahead and try this at home.,

Since the tension meter reads the true tension all you need is a spoke of the diameter you wish to calibrate for, a place to hang it from, and a basket or rack into which you can add known weights.

Hang the basket from the spoke, which in turn is held vertical at the other end. Load weights, take readings, calibrate.

I started to try this a while back and decided 120 kg was too much for any basket I could find and known weights that heavy are a bit of a problem.

I finally wound up with a bathroom scale, a car jack, and a 2x4 frame. I was trying to calibrate for some bladed spokes that didn't seem to be very tight when I got them up to the chart reading with my TM-1. This let me practice my technique also, since the TM-1 can give different readings depending on how you handle it.

I found that wiggling the TM-1 around a bit will cause the reading to decrease 2-5 units.

Yeah, you can make yourself the same thing with a crappy ass wheel you don't use.

1) Mark spoke with tape
2) Measure spoke with tensionmeter
3) Label spoke with tension

That cost... $5 worth of labour. And yeah, nice try with the for sale advertisement.

And this calibrates it, how????

Calibration means setting the measuring instrument against a reliable known standard. I don't see any standards here.


BTW-I shudder to imagine how you might calibrate your torque wrenches.

they didn't show the other end of the spoke, but it seems to me that a spoke nipple is the perfect way to add tension. Tension the spoke to whatever tension is desired as measured by the load cell. Looks like you could get an s-type load cell from ebay with a digital readout for less than $200 if you were a careful shopper.

We can't tell if it's really for sale or not. Leaving for now, no reason to report it unless you can read Korean and see where it's listed for sale.

Google's translation of the Korean text looks pretty benign:

Spoke Tension Gauge Calibration Fixture hwilpeuro using tension meters and gauges to measure the tension / checking / correction is a shape.

Hwilbilding bike shop specializes in working one, if the spoke tension gauge is used. Spoke tension meter environment, with frequent use over time can cause errors.

No matter how expensive, using precision engineered tension gauge any changes in the strength and spring tension meter, part abrasion / friction occurs and the accuracy is to fall. Spoke tension gauge to ensure the accuracy of the gauge calibration by the manufacturer to offer the service. Spoke tension meter for accurate calibration in a week, almost one month to be sent to overseas manufacturers follow the inconvenience.

If you are building specialized wheel spoke tension gauge calibration hwilbilding month or week depending on workload, daily, if necessary, and so is done on a regular basis. Shimano, Pro Lite, such as the establishment of professionally produced when the wheel spoke tension gauge tension in the calibration fixture handubeonssik day inspection / calibration uses a hwilbildinge.

Calibration tester under tension all the spokes on the spoke tension gauge measurements and accurate inspection / calibration is possible.
Also spoke about some additional tests are also available.

Even if gay, no matter how high the tension of the spring strength, part abrasion / friction may occur due to measurement error. The accuracy of the calibration tool does not check the spoke tension gauge tension gauge is a real tension values are wrong and correct without keunohcha there is no way to verify the accuracy of, but I measured bildingdoen wheel spoke tension be best way to evaluate only.

The figure below wheelsmith 130kgf DB14 spokes are measured by applying the load. DT spokes and all brands and types of spokes and hopefully in the desired load any value can be measured tension value.


The figure above calibration tool spoke tension gauge tension settings 130Kgf spoke tension gauge the accuracy of the FSA is to measure. FSA tension gauge Jobst Brandt is the author of the Bicycle Wheel produced by the FSA in the tension gauge is designed. Check the tension of the previously doubted the value of the curves on the chart to determine that there are some differences to find the cause has been resolved. Each designed by Jobst Brandt FSA spoke tension gauge the accuracy and repeatability of the gauge is very good, but like some other tension meter can do to correct the error because the screws on the basis of the measured test values hwilbildingsi tension is applied to the value. FSA spoke tension gauge Tension Meter features than other brands of low spring strength, so by applying the measure spoke tension indicator appears on the value of goal setting and can see almost no change. Changes in indicators at most 0.1 to 0.2 appears within. Also, depending on the type of spoke tension gauge fluctuations on the value is minimal.

Spoke tension gauge calibration settings in the Park tool tensioning tool 130Kgf TM-1 tension meter is to measure the accuracy of. The same calibration settings on the tool during measurement spoke tension is proportional to displacement by an increase in the indicator values that appear through Tension Meter Park tool FSA spring tension gauge the strength that is much larger than can be found. Repeat affordable entry-level and accuracy of the tension meter is excellent.

that's what I was going on. It appears that the OP is a careful wheelbuilder who wanted to share his technique for calibrating his spoke tension gages.

Even if it is a product ad, it still is an interesting device that could be duplicated locally at reasonable cost if you want to.

FBinNY's concept of using a known weight as a calibration standard is theoretically correct but probably impractical in real application. How do you hang 100 to 130 kg (220 to 286 pounds) from one spoke?

Easy:
1) find outhouse/garage/ patio or similar structure with exposed beams in ceiling.
2) find piece of sheet metal thick enough to simulate hub flange, preferably in the shape of a tab/strip several inches long
3) drill a spoke hole simulate in one end of the tab/strip, and several somewhat larger holes decently distributed at the other end
4) screw tab/strip into exposed overhead structural member, make sure spoke hole simulate protrudes enough for easy access
5) Create a rim simulate somehow. One way is to use another strip of the same sheet metal, folding it double around something to create a narrow U-shape rather than a narrow V-shape, drill spoke nipple hole at tip of U. Open end of U may be joined together by whatever means seems suitable and trustworthy. Pretty much anything goes, as long as you ca get piece of rope in there.
6) find piece of rope and a short lenght of plank/board
7) Create a crude bosun's chair out of plank and rope
8) hang spoke from flange simulate, hang rim simulate from spoke, hang bosun's chair from rim simulate
9) get on board the bosun's chair, clip on tensiometer. Record reading.
10) enlist heavier or lighter neighbour/relative/wrenching-riding pal - anyone brave enough to tell you their weight. Have him/her use the chair to get another reference point. Record reading.
11) to get to the higher readings the bosun's chair may be substituted by basically a couple of handles/trapeze, to allow several people to cling on simultaneously. You may want to add a safety tether to protect people from gettin hit in the head by the trapeze in case something in the contraption should break unexpectedly.

I would use some sort of lever arm to act as a force multiplier. Think of a 12" length of angle iron or bar stock, pinned at one end. Drill a hole 1" from the pinned end, and another at 10". The spoke/spoke nipple goes in at 1", and the weight is applied at the 10" location; simple 10:1 multiplier. For weight, I would use a 5 gallon plastic bucket and water (1kg per liter). With the lever arm, you would only need 10-13 liters.

You could build a simple rig, using the above principles, on a section of wood 2x4. For calibration, of course it would have to be vertical. I would just clamp the fixture to a door frame with some woodworkers bar clamps for the short time needed.

As the two prior posts demonstrate, a simple dead weight calibrator is easy to improvise if you have any creativity. In a most basic form a spoke can be added onto the rope of a tire swing hung from a tree and children and adults of known weight used for calibration (don't forget to add the weight of the tire.

In one of my first of similar systems, I made a sling and hung a set of barbells, making adding and removing weights easy and accurate.

I might point out that for the amateur wheelbuilder calibration is probably unnecessary. The tension meter doesn't get enough use to go far off standard, and in any case, the matching of tensions is unaffected by the raw accuracy of the device.

Some interesting ideas and creative ways to improvise a calibrator. As noted, most home wheelbuilders don't need to accurately calibrate a tension gauge, if they even have one, but it's nice to know it can be done cheaply. I like the leverage approach as it makes the necessary weights more manageable and you don't have to round up friends and relatives to use it.

While total tension on a spoke is important, I consider it a little less important for me, personally, than knowing I have even tension around the wheel which is where calibration of the tool is less important. I can use an uncalibrated tool and still get even tension.

tensiometer calibration
 

http://picasaweb.google.com/wheelwor...alibrationJig#

http://lh5.ggpht.com/_hvZowy161CI/Sq...0/DSCN7199.JPG

Absolutely, every home mechanic needs on of these.

need...
 

yes, this also...:D

http://farm6.static.flickr.com/5202/...beac0a_z_d.jpg
http://www.flickr.com/photos/anvilbikes/

That's exactly what I did to calibrate my homemade spoke tension meter. Instead of a weight, I used a cheap spring scale attached to a turnbuckle to apply the force. It needed a pivot at the end of the lever to keep the spoke from bending. It worked very well and the readings were accurate enough. It was necessary to calibrate my homemade gauge since the simple equations available online were were far off.