Getting way too high tension?!

Perhaps you could try a calibrator made for stringing machines. Just to be sure. Even if I tried one, and it's not easy to read the value on it, and I'm not pretty convinced it will make a difference. My digital scale is more practical and both have given the same result, more or less.

 

I've finally got round to taking some reference measurements and results are below. Indeed there is a ~2.5kg discrepancy across the board.





Measurements were taken using @Charlie-SWUK technique with the gripper finishing at about the 7 o'clock position.
Penta Premium have also concur with the view that the gripper should not be reversed or inverted to the 9 o'clock position.
They sent across the illustration below:


I've also had the opportunity to string a couple more rackets:

1. with gripper @9 o'clock position
14 x 15 kg = expected 32lbs
Per Stringer was 25lbs
Difference of 7lbs or 3.6kg

2. with gripper @9 o'clock position
15 x 16 kg = expected 34lbs
Per visor's thread on Pingtails I used Carltune app which reported a 26lb tension
Again, Difference of 8lbs or 3.4kg

3. with gripper @ 7 o'clock position
11.5 x 12.5 kg = expected 26lbs
Per visor's thread on Pingtails I used Carltune app which reported a 20lb tension
Difference of 6lbs or 2.7kg

So, string jobs 1 and 2 were performed incorrectly with the gripper at 9 o'clock hence the larger discrepancy. Stringjob 3 was performed correctly, and ties in with the graph I've plotted above.

I am completely baffled by what is causing this 2.5kg difference. Any other suggestions? Thanks all.

 

It’s a cheap machine (relatively). Quality control isn’t going to be at the same level of a £3k professional electronic tensioner setup! Don’t be surprised if the factory guidance is simply put the sticker x distance away from the pivot and they never actually check with scales.

Be happy you’ve found a fix, and now you’re confident your machine is well-calibrated! It’s like me buying a cheap bike because the ‘gears were broken’ and it turns out they were just not indexed right. 15 minutes later I’ve got a fully functional top-of-the-line bike

 

I think if the scale is faulty or the machine must be clarified if you change one of the them. Returning the machine is complicated so I suggest to buy a useable digital scale on ebay with DMS (strain gauge) instead of a spring (which can wear down easily). Depending what measuring tool you use it also have tolerances. The tools which measure in a small window are mostly more accurate. It's not uncommon that some tools for use at home have 5-10% tolerance from the maximum value. I wouldn't trust this scale. Get a digital one on ebay. I have this one which turned out accurate for me:

https://www.ebay.de/itm/Digitale-Ko...395756?hash=item3f91a42e6c:g:XgIAAOSwQwZaXLId

IMO it hasn't to do with gripper position or the lever position or any other small details which people here break down etc. get a proper scale. ASAP!

 

Dude, you really do have a cursed machine or something.

First of all, forget stringster as a credible reference. Can you share the racket model and ping frequency (CarlTune or Cleartune)? That would be way more telling and offers a chance to compare it with results from others.

And then, have you checked the calibration of the WISE? I'd rate it as unlikely to impossible, but maybe you got a badly calibrated one.

Edit:
Just noticed that you were using PS. So that already explains about 0,5 kg deviation already. I constantly get out results with 20-30 Hz higher pings if I use 10% PS.

 

Bin this Stringster-****. This App is totally rubbish. I strung various rackets which turned out spot on and several rackets which are totally off. 13kg on JS10 turn out on stringster at 14.1kg. 9.5kg on ZFII turned out at 10.6. At 11kg turned out 12.1. MX80 at 9.0 turn out 10.1 kg and so on even without PS. N7II always turn out 12.9 on 13 or 13.4 on 13.5. Use carltune and ditch stringster. IMO your machine is accurate and the app is ****. Don't worry. I used stringster on 3 (Sony, Sony, Huawei) different phones and 1 tablet (Samsung) and the device isn't the culprit. I got very often a 1.1kg higher reading, only on the N7ii I'm incompetend to string it higher than usual. Very suspect.

 

100% agreed. The results I got from Stringster were so random and dependant from the racket that I've deleted it in the meantime.

1250 Hz is at the tighter end, but fully within the expected range for the given setup I would say. Especially with 10% PS.

My advice: Enjoy your newly updated machine (which is a killer setup by the way!) and focus on ping frequencies if you want to have a control indicator for your process.

 

At the end of the day who cares about numbers? If something feels too loose add tension, if it feels too tight drop tension. Even customers can adjust after the first job on their request when too loose or too tight feeling occur. I normally mention for new customers "Alot people got the impression that my jobs are tighter than from others (those who use flying clamps, clamping 5cm from the frame, use crank and so on). Should I knock off 0.5 kg for your request?"

 

These guys really don't care about a superb string performance. They just count the month and judge by the durability. Easiest clients. You just need to scare them that increased tension needs less durabilty and they stay at 9.5kg max.

 

Guys, I'd like to revive this thread once more to ask anyone of you a favor. As some of you might know, I've started a (german) group on Facebook concerning badminton stringing and currently, I'm in contact with one colleague who is making the exact same mistake as the OP in the beginning: He pushes the lever down with his hand. And to show him and others the actual impact of that, it would be perfect to have a short video that shows the resulting tension on an installed fishing scale.

And since I'm no longer owning a drop weight machine myself - can anyone of you guys help me out and take a short video of this?
1) So let's say the drop weight is set at 10 kg and the lever is slightly above horizontal: Scale shows ~9.x kg
2) Then push down until it's horizontal and show the resulting numbers on the scale

The universe will thank you with a decent portion of good strining karma for this.

 

Sorry for the crappy quality, but you get the idea.

Note that I removed the locking mechanism that holds back the tensioner when lifting the weight.
You can see the bar raising back up when I released my finger because of it.
Imo this locking thing is annoying to deal with and slowing down the whole process.
I generally recommend removing it and it will likely fix the problem with incorrect tension too.
I would also suggest to get some kind of scale like I'm using here because the marks on the tension bar are fairly inaccurate.

 

Thanks a lot mate! Just to make sure that I read the numbers on the scale correctly - it's 9.8 kg in balance and goes up to around 13 kg with that gentle push applied, right?

 

Yep, that's right.
It's easier to see on a big screen.

 

I have the same machine and I completely agree with you about this locking mechanism. It slows the process and it's a p... in the a.. to unlock.