tension calibrator alternatives

#1
Seems many ppl use digital scale for tension calibration.

Just wonder any particular ones you recommend?

I searched a little bit, but found that many models do "lock" the reading after it stabilized. I am hoping to find one without locking feature, so I can keep monitoring the tension drawbacks.

Thanks.
 
#3
The Decut bow scale has instant readout and a lock out readout for peak reading. So it can measure peak (highest reading) and continuous (instant) weight, depending how you set the scale, one button changes the mode.
It was made for archery, and national archery judges use this to measure archery draw weight for national competitions, and compound bows have a peak draw weight and a let off draw weight and this measures both by either a fixed scale .My brother is an archery judge.
Scale is sold on big auction site very reasonable. Around $50.00 for plastic one, but... I suggest a few $ more and get the metal one as it is very strudy over the plastic one.
https://www.bing.com/images/search?view=detailV2&ccid=Brs7kv5g&id=BC9BFD61D7D0DD3C0A3B47C9E2981225456BABC2&thid=OIP.Brs7kv5gWFlX4EafpRzeUQHaE8&mediaurl=http://static1.shop033.com/resources/9D/157/picture/D0/86312912.jpg&exph=500&expw=750&q=decut+scale&simid=608044896281102411&selectedIndex=0
 
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struggle

Hall of Fame
#4
The Decut bow scale has instant readout and a lock out readout for peak reading. So it can measure peak and continuous weight, depending how you set the scale, one button changes the mode.
It was made for archery, and national archery judges use this to measure archery draw weight for national competitions.My brother is an archery judge.
Scale is sold on big auction site very reasonable. Around $50.00 for plastic one, but... I suggest a few $ more and get the metal one as it is very strudy over the plastic one.
https://www.bing.com/images/search?view=detailV2&ccid=Brs7kv5g&id=BC9BFD61D7D0DD3C0A3B47C9E2981225456BABC2&thid=OIP.Brs7kv5gWFlX4EafpRzeUQHaE8&mediaurl=http://static1.shop033.com/resources/9D/157/picture/D0/86312912.jpg&exph=500&expw=750&q=decut+scale&simid=608044896281102411&selectedIndex=0

Would you mind taking a picture of how you rig that?

I have two digital scales (with dead batteries) and a typical spring scale.

Honestly, I've never calibrated my Wise. I should do that (go get batteries).
I did use them on my lockout (eagnas 910) and they all varied abit, but the combo gave you a good idea of how to scratch your head.

On all my rigs i use kevlar and try to minimize friction on the pull (i pull over a sharpie, seems slick enough...).
 
#5
I just made 2 loops with 2 strings.Tie a big open loop on one end of scrap string and place loop around the handle of scale and loop the other end of that same string string through that tied open loop so string holds well to scale handle in middle of handle, as it is a hand held scale with other end to tension head, and other loop string from scale open clip, as it has a clip to hold string, to machine fixed clamp. Pull tension and read.This scale is designed to pull an archery bow string using your hand, so I just rigged up a string to hold in middle of handle, so scale is in middle with string on each end.
\Basically I rig it with this.. scale has one string on one with the clip end going to fixed clamp, other string tied to handle going to tension head with scale in middle between the 2 strings.
The scale is with my brother presently, as it is his scale.
To be honest I don't even bother to check my stringing machine any more as it always pulled accurately when I did check it.
The stringing machine I have goes through a calibration check on its own when I flip on the power switch, and I never had to calibrate it, and the few times I did check it with scale it was accurate.
 
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#7
Thanks. That Decut bow scale is quite expensive. Any low cost option? I used my friend's gamma calibrator to test my stringer, it is about 2lb higher. I didn't bother to adjust, just minus about 2lb around 50.
 
#8
I already had a digital scale that has a peak reading before I bought my Neos 1000. So I tried it and it worked fine. The one I have is made by American Weigh Scales (AWS) and the model number is PK-110. I paid $21 for it.
 
#9
Digital tennis calibrator made by Wise. Factory-calibrated (unlike fish scales). Quite inexpensive for what it is, at $65.

It does not lock.
 
#10
I got a digital luggage scale with peak hold a few years back I found on the internet for about $12

EDIT: There’s one like it on the auction site for $24 - $40 - Aws Pk-110 Peak Hold Digital Hanging Scale
 
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#11
For those who use luggage scales, why/how do you trust them to be effectively calibrated?

Do you ever check them with a test weight?
 
#12
For those who use luggage scales, why/how do you trust them to be effectively calibrated?

Do you ever check them with a test weight?
If you strung your racket and the tension was 2% off do you think you could tell? Federer sometimes varies his frames by a Kg or more and that’s about 4%.
 
#13
If you strung your racket and the tension was 2% off do you think you could tell? Federer sometimes varies his frames by a Kg or more and that’s about 4%.
The nature of tennis strings and the way they lose tension means low percentage point accuracy off the machine is probably not significant for the majority of 'real-world' players, but when many of us obsess about the details of stringing it seems inconsistent to set the baseline for a machine (i.e. the tension it pulls) by using something that is not intended for such use and appears to offer nothing to justify the confidence in it.

I guess context of the machine being used and who you are stringing for is relevant...but I would still want to know something was reasonably accurate before re-setting something.

Though of course for anyone not worried about inaccuracy why bother checking the calibration in the first place?

Hey ho, maybe it's me who is worrying too much about the detail.
 
#14
@R15 Nothing wrong with checking accuracy, so I did. My bag weighs 3.2 lbs when I add 10.0 lbs of weight at a time up to 50 the weight of the bag increases 10 lbs at a time up to 53.2 lbs. There is a little bit of wobble as I get up in weight and the 1/10 & 1/100 digit bounces a bit. So I assume the scale is fairly accurate. I do check my machine every time I clean the clamps.

EDIT: I'm a little on the OCD side myself at times.
 
#16
If you are OCD, you test the scale with known weights before using to check your machine. Peace of mind is priceless. :)
LMAO I'm not going to buy 50# of known weight .

EDIT: I guess I could take the weights I have to the gym and measure them on the balance scale.
 
#17
I guess I could take the weights I have to the gym and measure them on the balance scale.
Yeah... but then who's to say that the balance scale at the gym was calibrated?
Now you're gonna have to take that gym scale and...

Damn it!

(The Devil made me do it. :p)
 
#18
1 gal of water is ~8.34 lb. 5 gal bucket holds 41.7 lb of water. So, if the empty bucket weighs 2 lbs, a bucket with 5 gal should weigh 43.7 lb. Use 2 5 gal buckets if you need to go higher. A measuring cup is useful for many things. After calibrating/measuring, use the water in your garden. My scale was off by about 0.4-0.5 lb linearly. So, now you have a cheap way to check your luggage scale before using it to check your tension head. As I said, some of us are OCD.
 
#20
Buy a calibrated test weight. I had a 50lb certified weight I paid about $40 for 30 years ago. Now it runs over $200. Shop around and see what you can get locally.
 
#21
I took some advice from this thread and I wanted to share what I learned.

Lately, my stringbed tension (using RacquetTune) have been about 5lbs higher than what I have been expecting. Given that I have been getting better and faster at stringing, I have been thinking “what the heck is going on.......”

So based on Irvin and kdm711 recommendations and my interest in having a peak hold scale I purchased the AWS PK-110.

Having a spring and digital gauge allowed me confirm that my spring gauge was pretty accurate but what it really taught me was how important the speed of the pull was to tension accuracy.

When using the spring gauge it was so difficult to read it at point of lockout I had to pull very very slowly, but this wasn’t how I was cranking with normal stringing. Using the digital scale with peak hold I was able to pull normally wIthout having to read the gauge and guess what? Every pull was 5-8lbs higher than what I thought.

So I started experimenting with how to get my crank to be the most consistent in terms of tension. I then I adjusted the tension head for that approach and consistently pulled the same way every time. My next two racquets stringbeds were about 1lb high.

While I suppose I could have done this with my spring gauge, if I really knew what I was doing, but having the peakhold meter really opened my eyes.

Thanks to Irvin and Kmd711 for their suggestion which unit to buy.

Lastly, I know the old timers on this board say consistency, consistency, consistency but they really, really, really mean it, in all things.

Cheers Stephen
 
#22
So based on Irvin and kdm711 recommendations and my interest in having a peak hold scale I purchased the AWS PK-110.
That is the same one I have. Be careful when you set it down. It is very easy for it to come on and if you leave it on you may come back to a dead battery then you have to look around for your small phillips screw driver to change out the batteries.
 
#24
Well I'm going to chime in here and say that if I really really really really cared about producing totally consistent string jobs ....

I would ditch my LO Crank Stringer and replace it with a decent electronic CP machine!

"I say we take off and nuke the entire site from orbit. ... It's the only way to be sure."
 
#25
Understood. I think I have quite a way to go before LO vs CP is my limiting factor for consistent string jobs. Looking forward to getting there some day :)
 
#27
Bursting your hopes! There is no publicly available method for calibrating a WISE tension head. Company says to sent it back to them to calibrate. You could see if your pulls are at ref tension and if the deltas are linear, i.e. linear offset. Barring that, you are down the creek without a paddle.
 
#28
Bursting your hopes! There is no publicly available method for calibrating a WISE tension head. Company says to sent it back to them to calibrate. You could see if your pulls are at ref tension and if the deltas are linear, i.e. linear offset. Barring that, you are down the creek without a paddle.
Wow, I did not know that was the case. Now I'm glad I never purchased one of those.

In the unlikely event I ever move to an electronic machine, I will make sure I look at ones that I can calibrate myself. (Or are you suggesting that while there is no "public" method for doing it, it is possible to do anyway?)

OTOH, if I ever did decide to go for a CP stringer, I guess there are the obvious non-electronic offerings to consider.
 
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#29
Gamma and Alpha eCP can be calibrated. Pretty sure all the other major brands can be too. WISE probably could be, but then which POT screw do you turn once you open up the case? It definitely is not publicly known. Have never seen any method published.

Auto DW with fixed clamps are the next best alternative. Just get the weight close to horizontal and you're good. Slower than a LO.
 
#30
What is the correct way of using mechanical calibrator, like Pro's Pro? I have just received my Wise and Pro's Pro shows 2+ kg tension compared to ref. tension on Wise... Cannot understand if it is Wise or calibrator fault...
 
#31
You got the cheapest calibrator available on the market (around 12 euros or 15 USD) which does not even have a stated accuracy and which scale, I assume, barely has read-out precision of 1 or 2 kg. I would suspect that it is more likely the calibrator than the tensioner that is off.

This is what Wise has to say about calibration in the FAQ section on their web page:

“Can I calibrate the machine?
After every pull the machine resets its zero point and checks its electronics. If you have a scientific gauge to measure tension we can tell you how to calibrate the 2086 from the front panel. A spring calibrator is usually not accurate enough. At any time the machine can be sent to Wise USA for a free re-calibration checkup. We only charge for return shipping. Or, you can verify the accuracy of the 2086 using the precision of the Tennishead™ 2090, our professional programmable calibrator.

To put things into perspective, electronic tensioners are quite accurate by design and require high accuracy gauges for calbration. Mechanical tensioners may be off by much more, and spring based gauges tend to be useful and accurate enough for them. I remember there was a used NEOS offered for sale (I assume, by one of the customers) through the local tennis shop. While I already had an electronic machine, I was curious to learn how NEOS works, and store employees were happy to share their knowledge. I brought my 2090 calibrator to the store and found that its tensioner was somewhere around 15, if not 18 Lbs off - I cannot remember the exact number, but I was astonished how much off it was. A spring calibrator would go long ways with that machine to bring it back to calibration.

When you had a crank on your machine, the calibrator which you have was the right tool, but with Wise you need an upgraded calibrator as well.
 
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