***Stringway Machine Users Club***

Sergio Ilini

New User
Спасибо за ответ! Вне всякого сомнения MS 140 является лучшем станком с пружиной! Но я очень сожалею, что вы не довели до конца версию станка для путешествий. Версия типа MiStringer с установленной пружиной была бы идеальным вариантом!
 
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Technatic

Professional
Thanks for the answer! Without a doubt, the MS 140 is the best spring machine! But I am very sorry that you did not finish the version of the travel machine. A version like MiStringer with a spring installed would be perfect!
The MS140 is meant for travelling we supply it with a case. But we noticed that most users of the MS140 only use it at home and also prefer our standard racquet support. And therefore we launched the MS140LS.



We got this picture from a coach who travels with his son with the machine

 

Technatic

Professional
Hi Guys,

Because we are working on our “Instagram history” we find pictures that might be nice to show.

When we developed the Stringway stringcomputer the strings were classified in 4 classes based on the elongation. We did those first tests on a spring-test-machine with transducers for the elongation and the tension. The graphs were made on an X-Y recorder.



The graphs showed the big differences between the strings.


You can also see more pictures without having Instagram.

With this link and click on the picture to see the message

https://www.instagram.com/stringway.1982/?hl=nl
 
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Hi Sergio,

I put your message in the google translater so I assume that this is your message?



The MS150 was much too complicated to produce it is driven by a spring like the MS140.

But the MS140 is a much better product and better design to produce

The cradle system is the same as of the MS150.

Hi Fred,
Any hope that the MS150 will ever go into production?
 

Technatic

Professional
Hi Fred,
Any hope that the MS150 will ever go into production?
I would like to know what you like better on the MS150 than on the MS140?

I am sure that we will not make a production series of it:

- It was too complicated so too expensive.
- Too heavey for traveling.
- Not so easy to use as the MS140

 

Technatic

Professional
Another piece of history that we show on Instagram:

The route maps do the same as the Rucanor String computer and are actually the precursor of the online Tension Advisor:

By answering the questions the player got an advised string bed stiffness and type of string. The string bed stiffness was translated to stringing tensions for mains and crosses with the Tension Advisor calculation disk.

There was a route map for a man and a lady.



 

Technatic

Professional
@Irvine maybe you missed something:

This is history, we made these route maps in 1994.

We find these pictures because we are putting our history on Instagram.

https://www.instagram.com/stringway.1982/?hl=nl

And because we have the online Tension Advisor we do not sell the disc anymore.

We only have LBS discs still on stock and people who want this can have it for the shipping cost, just write me a pm.
 

Irvin

Talk Tennis Guru
@Irvine maybe you missed something:

This is history, we made these route maps in 1994.

We find these pictures because we are putting our history on Instagram.

https://www.instagram.com/stringway.1982/?hl=nl

And because we have the online Tension Advisor we do not sell the disc anymore.

We only have LBS discs still on stock and people who want this can have it for the shipping cost, just write me a pm.
Thanks but I'm happy with the online version and use it often. I just thought maybe the card version had something different.
 

Technatic

Professional
Around 1995 we started to organize seminars for stringers, we called it "From stringer to racquet tuner". The picture shows the differences:



Before we started the participants filled in a Quiz so that they could test their knowledge. Avarage score was very low 8 good out of 20 questions. Of course it was much more difficult to find stringing information without the internet.



With this link you can download our English version of de seminar.

http://www.stringway-nl.com/pdf/EN/SEMINAR ENG.pdf
 

Technatic

Professional
You can buy a digital scale for a couple of dollars, but in 1996 these systems very expensive. So we made a mechanical system for the tests and assembly of the MS200. The force bends the leaf spring and the clock measures the deflection. The system is calibrated so that one revolution on the clock is 10 kg force.

 
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Technatic

Professional
The stiffness and the stability of the spring of the MS200 was tested on a lathe.

Because of the high stiffness and very accurate displacement indication a lathe is a very good test bench.

 

Technatic

Professional
Hi Guys,

Still entering our history on Instagram coming to the year 2003 now.

Therefore this picture which might be useful for the good understanding about the tension in the racquet:

Friction plays an important role in stringing. It is the main reason that the tension in the string in the racquet is lower than applied by the tension system. Because there was a discussion on a forum we did a test to measure the friction in different situations.



Machines with 360 degree rotation of the turntable loose tension in the grommet because the string is pulled downwards.



It is the “art of the stringer” to minimize friction as much as possible.

Important principle of the Stringway tension system is that it pulls the string horizontal for minimum friction. When we would pull down it would cause a lot of loss of tension.

To maintain this principle and to minimize loss of tension in the mains ending in the bridge we developed the Concorde system.



At first the Concorde situation was activated by a handle but now the table lifts “automatically” when the handle of the racquet is rotated towards the tension system.
 
I would like to know what you like better on the MS150 than on the MS140?

I am sure that we will not make a production series of it:

- It was too complicated so too expensive.
- Too heavey for traveling.
- Not so easy to use as the MS140

Hi Fred,
Apologies for my late reply.
I much prefer the neat tension-head release lever of the MS150 than the awkward (to me) long lever used in the MS140, reminiscent of a drop-weight long rod.
I just think the MS150 is neater.
Besides, regarding its weight, no problem to me given most MS140 users don't seen to travel with it anyways.
 

gkenney

New User
The following tabulation was derived using the Stringway conversion chart as a basis. The data points from the Stringway conversion describe a relatively smooth curve so I felt it reasonable to assume the smooth nature of the curve would continue beyond the 13.0 KG/CM shown in the published conversion tabulation and graphic.

I have Yamaha Secret 04 and 06 racquets which have KG/CM stiffness ratings above the 13.0 KG/CM. I measured the Secret 04 at 17 KG/CM and the Secret 06 at 15.4 KG/CM. Others on the TW forum have stated the Secret 04 had an RA ~81 which was taken from an old review of the racquet and the Secret 06 had an RA of 78 (but the reference was even more ambiguous).

I took the conversion graphic provided by Stringway and extended the line further, doing my best to match the slope and curvature. After having done this in Photoshop I pulled the graphic into the Dagra graphic digitizer. This software allows for pulling data from graphs which can be put into spreadsheet applications like Excel.

After exporting the data produced by Dagra I imported it into Excel and (not surprisingly) the graphic produced was extremely similar to the Stringway conversion graphic and was very smooth. I was pleased that the 15.4 KG/CM was very close to the 78 RA provided by another source and the Secret 04 came to 80 RA which is very close to referenced RA noted above.

The utility of this data is perhaps dubious because of the lack of concrete references but it is perhaps better than the nothing I had to use for my racquets previously.

I have absolutely no idea as to whether this is of any use to anyone but myself, particularly since modern racquets having an RA over 70 are not in abundance. I believe information such as this should be shared instead of sitting on a hard drive. I know there is an equation for this data because the graphic is smooth but it is currently beyond my ability to tease out. I've read several times that the RA scale goes from 1 to 100 which is good information but it does not assist me in deducing an equation for this data. Unfortunately, producing the equation is not in my tool kit but perhaps there is a physicist or clever engineer who could perform the task with little strain just for the fun mental exercise.

The KG/CM data is reproducible by anyone having a Stringway Lab 2 and I admit knowing the RA does little (or nothing) for my game or equipment maintenance but I'm just a curious guy by nature.

KG/CM RA
4.5 => 21.6
5.0 => 29.6
5.5 => 35.9
6.0 => 41.4
6.5 => 45.9
7.0 => 49.7
7.5 => 52.9
8.0 => 55.9
8.5 => 58.6
9.0 => 60.8
9.5 => 62.9
10.0 => 64.7
10.5 => 66.4
11.0 => 67.9
11.5 => 69.3
12.0 => 70.6
12.5 => 71.8
13.0 => 73.2
13.5 => 74.4
14.0 => 75.3
14.5 => 76.1
15.0 => 77.0
15.5 => 77.8
16.0 => 78.6
16.5 => 79.3
17.0 => 80.0

Update: With an assist from esgee48 I was able to produce an equation using Excel trend line analysis. If you find this Excel formula disagreeable the fault lies fully on my plate. esgee48 simply advised me on how to find a formula for the data shown above.

Thanks very much!! I won't be doing anymore on this curiosity quest (actually I did more) but I've seen a number of times where people have asked for this translation/conversion equation and have been told it doesn't exist. Well, it still doesn't (actually) but this is the best approximation I could do. While Excel's trend line utility will display an equation I found it to be erratic (could very well be me) so I used the regression utility on http://www.xuru.org/rt/PR.asp#CopyPaste and increased the polynomial count to 8.

I'm very happy with the accuracy of the equation delivered but the accuracy of this equation and its utility is dependent the following: 1) the original accuracy of the conversion data from Stringway, 2) the assumption the data curve produced using the Stringway data continues smoothly past 13 kg\cm, and 3) my ability to accurately simulate the curvature of the graphed Stringway data past 13 kg\cm. Since the numbers are close to the Yamaha Secret 04 and 06 RA numbers I've seen from other sources I feel there is some hope of accuracy.

I used an 8th order polynomial and it’s within ~.1 RA for KG\CM values between 4.5 to 18. That is good enough for me but if someone wants it to be tighter they will need to increase the polynomial order until satisfied. Go outside the 4.5 to 18 range and the values are not reliable (producing ridiculous numbers). Inside that range the polynomial has a Coefficient of Determination: R2 = 9.999925589·10-1

The polynomial equation is: y = -2.493577256·10-7 x8 + 2.561143629·10-5 x7 - 1.144037698·10-3 x6 + 2.917184681·10-2 x5 - 4.678339064·10-1 x4 + 4.888608456 x3 - 33.22337151 x2 + 141.2515564 x - 239.9506264

Cut and paste the following Excel formula in cell B1 and put any KG\CM value between 4.5 to 18.0 in cell A1:

=-0.0000002493577256*(A1^8)+0.00002561143629*(A1^7)-0.001144037698*(A1^6)+0.02917184681*(A1^5)-0.4678339064*(A1^4)+4.888608456*(A1^3)-33.22337151*(A1^2)+141.2515564*A1-239.9506264


It will return a value within ~.1 RA of the values listed in the Stringway conversion chart.
 
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gkenney

New User
Wow @ Gkenney you are putting a lot of effort into this matter. (y) (y)
I'm a curious guy by nature ;). This has been fun and an exercise of synapses under utilized over the past several decades. There are people a lot smarter than me that could do much better with this but there is no return on time investment for such intellects to engage or care.
 
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