# **Stringway – information – Questions – answers**

#### Stringway Official

##### Rookie
Hello all

The intention of this thread is that Stringway can exchange technical information about stringing and about stringing tools online and hardware.

We have a “library” with pdf’s about stringing and racquet tuning and we would like to share them with anybody with or without a Stringway machine.

So please do not hesitate to come up with any questions that you have.

We hope that this discussion is useful for many.

Stringway

#### Stringway Official

##### Rookie
Every now and then we get this question about our “automatic” dropweight:
How does it work that the tension is the same for every angle?

These pictures show the difference in theory between the Stringway tensioner and a standard dropweight with or without ratchet system:

In words: The tension is the same for every angle because the relation between H and V is the same for every angle.

If you have any doubts or questions please let me know.

Fred

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#### Irvin

##### Talk Tennis Guru
@Technatic As shown in the auto DW example W (weight,) a (distance from the COM of weight to DW arm pivot,) and b (distance from pivot to string gripper) never change. But the angle A does change, so as the angle of the DW arm increases and decreases So does tension just like the normal DW.

EDIT: as the angle a changes the the distance from the pivot to the point at which the tensioned string leaves the gripper increases. As angle A changes up or down) force is lower on the DW arm side and the leverage on the opposite side increases. In short I think your diagram is wrong.

EDIT: I think the lines going to b (distance from pivot to string exiting gripper) should increase and be shown with b distance parallel to the distance.

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#### tennisbike

##### Professional
@Technatic As shown in the auto DW example W (weight,) a (distance from the COM of weight to DW arm pivot,) and b (distance from pivot to string gripper) never change. But the angle A does change, so as the angle of the DW arm increases and decreases So does tension just like the normal DW.

EDIT: as the angle a changes the the distance from the pivot to the point at which the tensioned string leaves the gripper increases. As angle A changes up or down) force is lower on the DW arm side and the leverage on the opposite side increases. In short I think your diagram is wrong.

EDIT: I think the lines going to b (distance from pivot to string exiting gripper) should increase and be shown with b distance parallel to the distance.
@Irvin The math appears to be correct. I think you are getting the feeling that this idea does not FEEL right. Our intuition says changing the angle will change the leverage, true. But that change happens on both sides at the same time. It goes up on the counter clockwise side, i.e. the DW, and it goes up on the clockwise direction, i.e. the tensioner side. And same times both went down at the same time as the DW moves away from horizontal. That is the beauty of the math, Te = W x (a/b) (same equation but an easier to understand version) Cos A dropped out on both sides of equation.

I get the feeling many people do not appreciate the beauty or the simplicity of using math to express the reality around us. It is really beautiful.. so pure, relationships distilled to the essence. Just pure truth.

When A is larger though, I do see that fillet or radius there the string might be going, that means b might get longer. So we do want to keep A reasonable.

I would love to use the automatic drop-weight machine. So simple and so effective. Plus my wife would appreciate not having the loud noise of the ratchet clicking when I am stringing.

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#### Stringway Official

##### Rookie

I do not think that we agree:
When the angle A increases, H and V decrease and vice versa.
So both the lever of the tensioned string and the lever of the weight increase and decrease in the same rate.
This makes the tension independent of the angle.

This is the test that we did for a German customer who wanted to be sure we measured it with a digital and mechanical tension tester. As you can see the difference in tension is very small.

This is the system that we use to adjust every Tension head individually

This list shows how small the difference in Tension is in the different angles .
The Tension for FSP< 90 (= tension head fully forwards) is less accurate because the radius of the upper jaw pushes the string down.

But this inaccuracy is not functional because it is not in the range where the tensioner will be used with stringing.

#### tennisbike

##### Professional
I do appreciate the test figures from the manufacturer. It is impressive +/- 25 degree yields difference within 1%.

I do not have a question merely a comment, the only thing I can wish for is not having to reset the string on tensioner when the string stretch too far, like on Ashaway ZXP. I am simply talking out loud and not expecting a response actually. I think how much string to leave out to put onto the tensioner seems to be just one thing the stringer need to make adjustment for automatic DW machines.

#### Irvin

##### Talk Tennis Guru
I do not think that we agree:
When the angle A increases, H and V decrease and vice versa.
As the DW bar is off level H will decrease whether the angle A is up or down. Since the force applied (H * cos A) goes down distance V must go up to maintain tension. If distances H and V both go down by the cos A your ref tension goes down.

EDIT: if both decrease by cos A your tension decreases by cos A

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#### tennisbike

##### Professional
In a static situation, i.e. not spining faster:
Torque CCW = Torque CW, next
DW x (leverage of dw) = tension x (leverage of tensioner)
if we decrease the leverage by say dropping below horizontal, decrease by same factor, i.e. change of cos of A
DW x (leverage of dw) x (fractional decrease) = tension x (leverage of tensioner) x (fractional decrease)

Trust the math.

Torque on both side goes down but the force on both sides remain constant because the leverage change by the same factor.

#### Stringway Official

##### Rookie
I do not have a question merely a comment, the only thing I can wish for is not having to reset the string on tensioner when the string stretch too far, like on Ashaway ZXP. I am simply talking out loud and not expecting a response actually.

@tennisbike
The intention of this thread is that we inform the user and answer any question that he has.
About using the tensioner for stretchy strings:
When the tensioner reaches the end stop lift the lever tighten the string, and pull again and do this without moving the clamps.

The string needs less travel when it is tensioned for the second time.

Stretchy strings have more remaining elasticity than stiffer strings. This remaining elongation occurs only the first time that you pull.
Keep in mind that remaining elongation developes slowly on "slow strings".

Other solution is: To prestretch the full length of string by hand at maximum hand craft before stringing.

As you may know from our Tension advisor more stretchy strings should be used at lower tension.

#### marco forehand

##### Semi-Pro
could you go into more detail on the subject of lower tensions for "more stretchy strings "?

#### Stringway Official

##### Rookie
could you go into more detail on the subject of lower tensions for "more stretchy strings "?

Ofcourse:
The intention of more stretchy strings is that the player gets a more convenient feeling when he hits.

But what the player feels depends first and mainly on the string bed stiffness:
The deflection of the string bed during a hit depends on the Sbs.
When the deflection is only small the string does not stretch at all.

The player feels the “stretch quality” only when the deflection is so high that the string actually stretches.
So the lower the tension the more the player feels the quality of the stretchy string.
Or when the sbs is too high the player does not feel the quality of the stretchy string at all.

There is another reason that stretchy strings should not be strung at higher tension:
The difference between a stiff and a stretchy string is in the remaining elongation.
The more remaining elongation and the higher the tension the more the string will loose tension.

Our list with string tests show elastic and remaining elongation and the strings divided in 4 classes (+ a class “bad strings”with too much elongation).

As company official I am not allowed to post links, but if you send me an email I will be glad to send anybody the list and a description of the test.
My email address is Stringway.fred@gmail.com

#### First Serve

##### Rookie
@Stringway Official

[

If you have any doubts or questions please let me know.

Fred

Thanks very much for sharing the kinematics and the premise of your stringer relative to a traditional drop weight, but I am having trouble with your Math (kinematics analysis.)

While I agree with your balance of Torques: W*H = Te*V, I disagree with how you resolve H (the lever/moment arm) on your Stringway calcs.

Firstly the Angle A should be to the center line axis of the shaft (but that is minor assuming shaft dia is small), but the main question I have is your (Stringway) equating H=a*cosA*V. I dont think that is correct. How does V come into play? H as in the 2nd example with the ratchet should be equal to =a*cosA. The rest of the analysis should result from that. (EDIT: unless there is some articulation/translation of the pivot point I dont understand, but I cant see that from your sketch)

This is also evident since you also show H = b*cosA. Visually and to your scale b is smaller than H. Multiplying b by any cosine (except for zero) would be even smaller. I am sorry but I am having trouble with this analysis.

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#### Stringway Official

##### Rookie
but the main question I have is your (Stringway) equating H=a*cosA*V. I dont think that is correct.
@ first serve
You are right that this quating is wrong but I can not find it in my picture?

#### First Serve

##### Rookie
@Stringway Official

Thanks for your reply. I see the equation on the 2nd line above.
" H = a cosA V = b cosA "

#### Stringway Official

##### Rookie
Thanks for your reply. I see the equation on the 2nd line above.
" H = a cosA V = b cosA "

These are 2 equations it would have been better when there was a comma between them.

#### Stringway Official

##### Rookie
Hi guys,
About the comments that I get (also in a pm) about the pictures which illustrate the theory of the tension head.
These pictures come from our Solid Works 3 D system illustrated in ACDsee.
I hope that you understand that these pictures are meant to illustrate the calculation and not to be perfect technical drawings .

When the pictures show faults I will certainly correct it but I am not going to change them only to make them more perfect.

We will use these kind of pictures more often so I hope that you can accept the imperfection.

Thanks
Fred

#### First Serve

##### Rookie
These are 2 equations it would have been better when there was a comma between them.
My background is actually engineering. This is why I enjoyed your analysis.

I just don't understand the equality and its derivation. Anyways thanks for sharing. I also enjoyed the German headings in the test data and recognize their handwriting characteristics if I am not mistaken.

#### Stringway Official

##### Rookie
A little more about how our “automatic”drop weight system functions:
All machines have an automatic locking system:
When the user lifts the lever and takes the string out of the clamp the tension head locks in the starting position.
This lock is automatically released when the user lifts the lever again, enters the string and lowers the lever.

This is how it works

This picture shows the locked situation.

When the string clamp opens part S5, with the release cam, moves forward in relation to the disc S10.
This means that the release cam meets the release roller and pushes the locking bar down before the locking bar locks.
This picture shows the released situation so that the disc can pass the locking bar.

The lock is released when a string of 0,7 mm is clamped. This asks for a very accurate adjustment of every individual tension head.
This picture shows the tool that we use for the adjustment system, is already in function since 1985.

#### Stringway Official

##### Rookie
You can see much more pictures in our History on our Instagram account of stringway.1982

#### Stringway Official

##### Rookie
could you go into more detail on the subject of lower tensions for "more stretchy strings "?

This is why our online Tension Advisor advices a string bed stiffness in combination with a type of string (S1 - S4)

#### Stringway Official

##### Rookie
The racquet moves!!!!
Every now and then we get an email from a stringer saying “the racquet moves when I tension the cross strings”.

The main task of the racquet support is to protect it against the forces of the main strings. After stringing there should be balance between the forces of the mains and the crosses.
When the racquet moves it tells that the racquet is in balance again and that the help of the supports is no longer needed.
The racquet does not have any problem when it moves a little so there is no reason to overtighten the clamps!

Moves too early!
When the racquet moves already, when a quite a number of cross strings still has to be strung, there is something wrong: The tension on the cross strings is too high so that the length of the racquet gets longer than it was before stringing.

How should it be.
Any racquet support must be adjusted so that there is a little pressure between the supports and the racquet. When the perfect string job is finished the pressure between the supports and the racquet should be the same as when the racquet was clamped.

If the pressure is higher on inside supports, the length of the racquet is still too small and the tension on the crosses was too low and when it is lower this tension was too high.

Check.
The important check on the used tensions is to compare length and width of the string area before and after stringing. When there is a difference adjust the tensions the next time you string this racquet.

Calculate tensions.
Our online tension advisor is calculates the stringing tensions, so that the remaining stress in the racquet is minimum. The result depends on the length and width of the string area and the number of mains and crosses.

#### Stringway Official

##### Rookie
We were out of stock on double and triple flying clamps because Covid19 delayed the shipment (not from China but from 100 km down the road).
But we have received the castings and will assemble a lot of clamps next week.

This picture shows the use of the triple and the double.
The quality of the triple is that it clamps 3 main strings and rotates less than a double flying clamp.
Therefore it probably looses less tension than many fixed clamps because it also does not have a “leak way” to the frame.

#### Stringway Official

##### Rookie
In the thread about prestretching polys we told about our elongation tests.

This is how we started the tests on a spring test machine.

#### MathieuR

##### Hall of Fame
it also does not have a “leak way” to the frame.
Could you please elucidate what this is, and when it happens

#### LttlElvis

##### Professional
@ Stringway Official. Thanks for all the pictures and diagrams! I really do enjoy your explanation. Hope to read more about the design of the clamps and mounting system and what makes them stand out over others. Also would like to read about the breakdown of how the MS200 works. Keep it going!

I had to search this YouTube vid. Never realized it was a giant spring in MS200. How is it calibrated?

#### Stringway Official

##### Rookie
it also does not have a “leak way” to the frame.
Could you please elucidate what this is, and when it happens

You can compare this with electric current, when there is no connection there is no current.

When the fixed clamp takes over the force from the tension unit the energy (=Force * distance) goes into the guiding system of the clamp system.

When the tension unit takes over with the next pull the guiding system does not return all the energy that went in, because of the friction in the system.

Because of the energy that is lost in the frictions not all of the drawback of the clamp disappears in the next pull.

With the triple clamp the “holding energy” goes into the 2 earlier strings and the displacement is only small. The strings are elastic elements and return most of the energy back with the next pull.

That is why the triple clamp can loose less tension than fixed clamps depending on the quality of the fixed clamp system.

That is why it is better to have high quality flying clamps than bad fixed clamps

#### Stringway Official

##### Rookie
@ Stringway Official. Thanks for all the pictures and diagrams! I really do enjoy your explanation. Keep it going!

Of course it is very motivating to hear this.

Hope to read more about the design of the clamps

“The quality of a design is in the details”;
The string is not damaged because of all the rounded edges, and the force of the lever system is adjustable accurately.

The aluminium castings make the clamp very stiff compared to the plastic copies, which bent so much that part of the clamping force is lost.

The funny thing about a 36 year old mechanical design is that it is very difficult to beat. It is the opposite of a smart phone.

and mounting system and what makes them stand out over others.

I will tell more about the racquet support in a next post. Actually the same counts for this as for the clamps being 28 years old.

Also would like to read about the breakdown of how the MS200 works.
I had to search this YouTube vid. Never realized it was a giant spring in MS200. How is it calibrated?

The spring of the MS200 (and MS140) is often compared with the spring of a lock out machine but the function is completely different:

In the MS200 and MS140 the spring is the “drive system” which pulls tension on the string, in the lock out machine the spring is only a reference for the brake function.

When the pedal is pushed down the spring is “loaded” when the spring is entered and the pedal is released the automatic lock releases and the spring tensions the string.

This graph shows how accurate the spring system keeps the tension constant.

In mechanics the spring is a very very very reliable drive system, compare it with the valve springs in a car engine which close the valves thousands times every minute for many years.

In the stringing world the reliability of the spring is uncomparable with all the complicated electronic systems.
And it is nearly impossible for an electronic machine to match the accuracy of a spring system.

The major principle of the MS machines is that the spring is over-dimensioned for the job it has to do. Therefore the loss of spring force is minimum and the spring lasts “for ever”.

There are MS200’s from 1992 which are still working perfectly and we never replace a spring.

This picture shows the drive system.

The calibration is very easy: The tensioner is adjusted at 44 lbs / 20 kg, the calibrator is tensioned and when the mark is correct the tension is ok.

If not the tension can be adjusted with the calibration bolt

When stringers forget to calibrate regularly the effect on the string job is minimum.

This picture shows the the functions of the tension head

More about the spring driven MS140 in a next post.

#### Stringway Official

##### Rookie
This picture shows the principle of the MS140 it is high quality through simplicity and therefore high stringing quality for every euro.

#### Karma Tennis

##### Legend
All of this stuff is sheer genius !!!

I have to stop reading this thread because it is going to convince me to purchase a Stringway machine ... even though the current Exchange Rate between the Australian Dollar and the Euro is the worst it has been for years .... but more importantly because I'm only stringing 2 racquets a month at the moment so it would be a total waste.

Excuse me while I go and admire the Stringway Mk2 Cross Stringing tools that I have in my kit. I have to relieve this tension some how !!!

#### Stringway Official

##### Rookie
@karma
Thank you for these compliments, sorry about your conflict.

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#### Stringway Official

##### Rookie
Some more features of the MS140.

We only supply it with the standard Stringway 5 point direct support, because that is what stringers prefer.

With the MS140LS the user can raise the tension in 4 steps of 0,5 kg with the red lever.

There is a table lock to lock the table in 6 positions, this pictures shows the needle bearing for the step- function- cam and the table lock in 2 positions.

An this is the cam

If anything is not clear please let me know.

#### LttlElvis

##### Professional
I have no reason to purchase a new stringing machine, but reading this thread, I want to get me a Stringway

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#### Stringway Official

##### Rookie
Hope to read more about the design of the clamps and mounting system and what makes them stand out over others.

@littlElvis
I still owe you some information about the design of our racquet support, but it was too busy the last couple of weeks.

* But hereby our “racquet support history”:

When we developed our first stringing machine in 1984, all stringing machines on the market had a “2-point support” with “bananas at 6 and 12 o’clock.

* The Ektelon H model was in use “everywhere”.

Stringing tensions were much higher than nowadays and racquets were by far not so strong.
>> Nothing went wrong.

We chose for a 3 point support at the head and a banana at the throat.

* Oversize racquets were invented and Prince came with their 110 sq in aluminum racquet which had to be strung at 72 lbs!
Nothing went wrong on the 2-point supports despite the high tensions!

* But stringers saw much more widening of the racquet head during stringing.
So there was a “smart guy” who invented the “3 – 9 cross bar”, which avoided every widening of the racquet during stringing.

>>>>>>>>> THE RACQUETS BROKE ON THE MACHINE!

So the cross bar disappeared faster than it came, I could not even find a picture on the internet.

The lesson was: If you minimize the deformation of the racquet, the stress in the racquet material will be so high that it cracks.

>>>>> IT IS NOT THE DEFORMATION THAT HARMS THE RACQUET, IT IS THE STRESS IN THE MATERIAL.

In 1992 we developed 2 new machines, the foot-operated MS200 and the electric EM400

Because we wanted a solid basis for the design of the racquet support I asked my colleague on the Dutch Nuclear Research Centre if he could make a computer calculation which showed the stress in the racquet for every type of racquet support.

The calculation was made for the head side of a 110 sq in racquet because the throat side is much stronger.

This graph shows the best position of the supports for 3 options

The conclusions can be:
- A 3-point support with supports on 52 mm from the centre offers the best results.

- A 2-point support (like Ektelon) offers quite good support.

- With outside supports the stress in the racquet depends strongly on the position of the supports. For 110 sqin the best position is at 175, the smaller the racquet head the smaller the distance.

Based on this theory we designed our racquet support “O92” with 3 wide supports at the head side and 2 height-adjustable supports on the throat side.

Apart from the position of the supports it is important that these are very wide so that the pressure between the racquet and the support is low.

The system had a fast clamp system with smooth pins; push down the clamp and rotate the knob 2 revolutions.

In 1998 German string manufacturer Kirschbaum asked us to design a better looking stringing machine than the EM400, the result was the EM500 with an upgrade of our O92 system.

We still use this exact system only with screw hooks instead of the fast clamp system.

For round, tapered or narrow bridges the Babolat retainer is use.

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#### LttlElvis

##### Professional
Once again, very nice documentation and explanations. Many thanks. Very enjoyable to learn the Stringway background.

Interesting how the 3-9 o’clock cross bar caused more damage. I used this on my TR stringer when I was a kid

#### Karma Tennis

##### Legend
The conclusions can be:
- A 3-point support with supports on 52 mm from the centre offers the best results.

- A 2-point support (like Ektelon) offers quite good support.

- With outside supports the stress in the racquet depends strongly on the position of the supports. For 100 sqin the best position is at 175, the smaller the racquet head the smaller the distance.

Fred, What do you think about those little plastic load spreaders that can be purchased from various places? Do they offer any additional protection to the frame during the stringing process? (Especially on machines that have outside supports)

#### Stringway Official

##### Rookie
Interesting how the 3-9 o’clock cross bar caused more damage. I used this on my TR stringer when I was a kid.

A little more explanation:

We distinguish direct and indirect racquet support.

The direct support works directly against the forces of the main strings and ensures that the racket does not become shorter (and therefore not wider).

The indirect support prevents the racket from getting wider, but the force on the outer supports must be "transferred" to the position of the main strings.
This causes bending stress in the racket at 2 and 10 o'clock.

The graph shows that the tension in the racket with outside supports increases when the supports are placed closer to 3 and 9 o'clock.

The tension is maximum with the supports at 3 and 9 o'clock and therefore the rackets broke with the "3-9 o'clock support bar".

The worst thing to do is to string badminton racquets on a tennis machine with fixed indirect supports.

These pictures illustrates the best way to support the racquet by comparing it with a beam in the wall.

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#### Stringway Official

##### Rookie
Fred, What do you think about those little plastic load spreaders that can be purchased from various places? Do they offer any additional protection to the frame during the stringing process? (Especially on machines that have outside supports)

Load spreaders are very good on indirect supports, racquets are often damaged on 6 and 12 o’clock by the central supports because these are much too narrow.

The old day bananas were load spreaders also.

The spreader only lowers the bending stress when it has exactly the same shape as the racquet, that is why we chose the 3 point support with very wide supports

#### Stringway Official

##### Rookie
Just to show how our Quality control works:

Every product has a check list for the assembly.

This is the list for the Spring driven MS140

#### Agassiup

##### New User
Hi Fred
What is the difference between the con (concord version) of the stringers vs non-con. Also, how does it effect the speed and maneuverability during the stringins ? Any effect on the accuracy?
Thank you!

#### AceyMan

##### Professional
Hi Fred
What is the difference between the con (concord version) of the stringers vs non-con. Also, how does it effect the speed and maneuverability during the stringins ? Any effect on the accuracy?
Thank you!

I'm not Fred, but I can tell you as an ML120con owner.

Concorde system has the turntable spindle (the upright hardened steel bar the turntable base spins on) hinged via a massive through bolt (? 12mm diameter) whose axis is orthogonal (East to West) with respect to the tension assembly.

This hinge allows the turntable to tilt exactly opposite (away) from the tension head. It's strongly spring-loaded to return upright. It doesn't affect accuracy since the table returns to true/square once the tipping force is removed.

When rotating the turntable, as the bridge/handle end nears the tension head position, a tapered block (shaped like \__/ ) under the turntable rides over a little wheel mounted within the turntable main beam.

Due to the angle of the block, this tips the turntable up (using the hinge capability described above) so the throat mains path to the tensioner runs under the handle of the racquet, avoiding the usual need to route the string across (above or below) the frame itself to reach the tension head.

As a result, the string has a straight line from the throat grommet and need not drag against the frame (as would normally be required).

/Acey

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#### Agassiup

##### New User
Thank you Acey! Hard to picture
how does it effect the speed and maneuverability during the stringins ?

#### AceyMan

##### Professional
Thank you Acey! Hard to picture
how does it effect the speed and maneuverability during the stringins ?

No effect at all.

In fact, if anything, it enables greater speed, because with Concorde you can lift the grip up over the tension head to "get to the other side" and not have to spin the frame 320 degres when you need to reverse sides of the hoop.

Note that the "Concorde block" tips the turntable just enough to allow the strings a clear line to the tensioner gripper, no higher. The grip then is about level with the tension head, but there is still hinge range to lift the grip a little more (against that strong return spring) so you can move the handle over to the other side of the tensioner.

I end up doing that a few times during most string jobs. The turntable spins like a dream, but sometimes lifting it over seems like the thing to do, especially when you have a long tail¹ remaining using a string having abundant coil memory.

/Acey

¹—I string one piece/ATW when I can, so there's a long side that's ... pretty long ... for a while.

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#### Stringway Official

##### Rookie
Hi Fred
What is the difference between the con (concord version) of the stringers vs non-con. Also, how does it effect the speed and maneuverability during the stringins ? Any effect on the accuracy?
Thank you!

@AceyMan
Thanks for the explanation, I wrote this one already so I post it.

An important principle of the Stringway machines is that the string is tensioned in a horizontal line, because when you pull under an angle you loose tension. The stiffer and rougher the string the higher the lost of tension.

The consequence of this principle is that it is more difficult to pull tension on the main strings in the bridge.

The “Automatic” Concorde system makes it much easier to tension the mains in the bridge.

When the handle of the racquet is pushed towards the tension system the table tilts “automatically”.

The cam under the turntable meets the wheel on the frame and the table is pushed upwards.

So it makes it easier (faster) and more accurate than without a Concorde system.

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#### Stringway Official

##### Rookie
One more remark:

Some stringers find it an advantage of the Concorde system the turntable can rotate 360 degrees.

I never understood the importance of 360 degrees:
- The string can be wrapped around the machine.
- It is very logic to turn “up and down” and tension the strings in sequence 5 >12>7 , 7>12>5 o´clock.

But, buying a machine with 360 degrees means the consequence of loss of tension on all strings, because of the additional friction

#### Stringway Official

##### Rookie
To learn more about the loss of tension when pulling tension in angles we once did a test;
The tensioner pulls tension on one side and the force transducer measures what is left on the other side of the friction.

This table shows the results for different systems and different height / angles.

As you can see the inaccuracy depends on the angle and is higher with stiff monos than more flexible multis.

#### onehandbh

##### G.O.A.T.
@Irvin @tennisbike @Stringway Official ,

About 5 years ago, out of curiosity, I did a test measuring the tension pulled at various angles. I did this on my ML90, which I purchased in 2010 and still use today as my primary stringer.

#### onehandbh

##### G.O.A.T.
The racquet moves!!!!
Every now and then we get an email from a stringer saying “the racquet moves when I tension the cross strings”.

The main task of the racquet support is to protect it against the forces of the main strings. After stringing there should be balance between the forces of the mains and the crosses.
When the racquet moves it tells that the racquet is in balance again and that the help of the supports is no longer needed.
The racquet does not have any problem when it moves a little so there is no reason to overtighten the clamps!

Moves too early!
When the racquet moves already, when a quite a number of cross strings still has to be strung, there is something wrong: The tension on the cross strings is too high so that the length of the racquet gets longer than it was before stringing.

How should it be.
Any racquet support must be adjusted so that there is a little pressure between the supports and the racquet. When the perfect string job is finished the pressure between the supports and the racquet should be the same as when the racquet was clamped.

If the pressure is higher on inside supports, the length of the racquet is still too small and the tension on the crosses was too low and when it is lower this tension was too high.

Check.
The important check on the used tensions is to compare length and width of the string area before and after stringing. When there is a difference adjust the tensions the next time you string this racquet.

Calculate tensions.
Our online tension advisor is calculates the stringing tensions, so that the remaining stress in the racquet is minimum. The result depends on the length and width of the string area and the number of mains and crosses.

I have a couple Yonex "square" head racquets (Yonex 95D & R22). Does this calculator take the irregular Yonex head into account when calculating the suggested tensions for the mains & crosses?

#### Stringway Official

##### Rookie
I have a couple Yonex "square" head racquets (Yonex 95D & R22). Does this calculator take the irregular Yonex head into account when calculating the suggested tensions for the mains & crosses?

Yes the calculator can be used for any shape of head because it does not calculate with the shape, it works as follows.

The system calculates the Tension on the crosses which is need to undo the widening of the racquet caused by the tension on the mains. The basis is the length and width of the string area and the number of strings to do so.

The intention is to keep the deformation as small as possible and to obtain the desired Dt value.

The check is easy: Compare the length and width of the string area before and after stringing.

If the difference is small the tensions were ok.

If the difference is bigger compensate the next time you string the racquet.

Iow if the length is smaller after stringing raise the tension on the crosses or lower the tension on the mains (depending on the DT value you want to achieve).

VERY IMPORTANT:
Do not be afraid to string the crosses at higher tensions than the mains. The experience with 8 kg more on the crosses with the Wilson 18x16 has proven that the calculations are quite ok!

I

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#### Stringway Official

##### Rookie
A little more information about our floorstand for the ML100.

We do not keep this stand on stock because those stringers who want an upright machine order the ML120.
But we received some requests for the floor stand from ML100 owners.

Therefore we make a special series which can be ordered before we make them.

The stand will be available in November and in one height of 83 cm.

The stand can also be used for the light weight MS140, but we do advise a special “weight trick” for the most convenient use.

#### Spin Diesel

##### Hall of Fame
Hi, I‘m thinking about stringing for myself, since I calculated it would pay off much sooner than I thought. So I‘m pretty much about to buy a ML100. Regarding prestretch, is it possible to leave the strings under tension for a few more seconds then usual, in order to eliminate the most severe initial tension loss? So it still pulls at the set tension even if it‘s a string that looses a lot of tension?
And how long do you think will it take a beginner to achieve somewhat consistent results. I guess the fixed clamp version is easier to use, right?
Cheers

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