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-   -   constant pull vs crank (http://tt.tennis-warehouse.com/showthread.php?t=197845)

rscottdds 05-15-2008 09:01 PM

constant pull vs crank
 
Are constant pull machines better than cranks as far as racquet playability is concerned? I know consistency is the name of the game, and if you can string a racquet the same every time it doesn't mater what kind of a machine you use. However it would seem easier to get a consistent string bed with a constant pull machine. Is this true? And if so does it really matter? Can the above average player tell the difference as far as playability is concerned if you indeed get a more consistent string bed?
-Robert

YULitle 05-15-2008 09:45 PM

Consistency comes from the stringer first and foremost.

rscottdds 05-16-2008 06:13 AM

Quote:

Originally Posted by YULitle (Post 2338345)
Consistency comes from the stringer first and foremost.

And I realize this. However I have a very accurate measuring devise and when I pull with a lockout machine, I can get differences with each pull. I assume with a CP machine these differences would be minimized. Does this translate to a difference on the court for a college level player and above? I'm wondering if it is worth it to change to a CP machine (ie buy something like a wise)
-Robert

YULitle 05-16-2008 06:15 AM

Quote:

Originally Posted by rscottdds (Post 2338985)
And I realize this. However I have a very accurate measuring devise and when I pull with a lockout machine, I can get differences with each pull. I assume with a CP machine these differences would be minimized. Does this translate to a difference on the court for a college level player and above? I'm wondering if it is worth it to change to a CP machine (ie buy something like a wise)
-Robert

Care to document those differences? It would help me get an idea of what you are expecting from an electric-CP as far as consistency goes. Accuracy is in the eye of the beholder afterall.

MAX PLY 05-16-2008 06:43 AM

Quote:

Originally Posted by rscottdds (Post 2338985)
And I realize this. However I have a very accurate measuring devise and when I pull with a lockout machine, I can get differences with each pull. I assume with a CP machine these differences would be minimized. Does this translate to a difference on the court for a college level player and above? I'm wondering if it is worth it to change to a CP machine (ie buy something like a wise)
-Robert

Interesting. I have two calibration devices--one the "normal" cylindrical and a Prince digital--they are both generally spot on and I have not incurred the phenomonon you describe on my Neos. What sort of string are you using in the calibrator? Are you testing at different distances from the clamped device?

wumanchu23 05-16-2008 06:52 AM

I hear the term "calibrate" alot when it comes to crank machines. I think someone said it takes very little time, and they don't calibrate it unless they moved the machine or felt like theres a need to do it. I'm kind of new to this, what tools are required when it comes to calibration. Does the machine have to be brought to a shop?

YULitle 05-16-2008 06:58 AM

Quote:

Originally Posted by wumanchu23 (Post 2339079)
I hear the term "calibrate" alot when it comes to crank machines. I think someone said it takes very little time, and they don't calibrate it unless they moved the machine or felt like theres a need to do it. I'm kind of new to this, what tools are required when it comes to calibration. Does the machine have to be brought to a shop?

It just takes a calibrator (which tests the tension actually being pulled) and the appropriate hex wrenches (or other tools) required by the machine. Most machines can be calibrated at home.

MAX PLY 05-16-2008 07:03 AM

Quote:

Originally Posted by wumanchu23 (Post 2339079)
I hear the term "calibrate" alot when it comes to crank machines. I think someone said it takes very little time, and they don't calibrate it unless they moved the machine or felt like theres a need to do it. I'm kind of new to this, what tools are required when it comes to calibration. Does the machine have to be brought to a shop?

Basically you will need a tension calibrator (available from TW) and what ever tools are required to adjust your crank mechanism (should detail in your machine manual). The details vary from machine to machine but essentially the calibrator has string on each end. One end goes in your clamps (the tray will need to be stationary (i.e., brake on)) the other end fits in your tension head (just like pulling tension while stringing a racquet). You want to verify that the calibrator and your reference tension are in synch--if not, adjust your tension head appropriately. You should be able to do this yourself. Hopefully, your machine manual details the specifics for your machine. Good luck.

fastdunn 05-16-2008 09:53 AM

in strining process, there are many variables you want to try to be consistent about.
constant pull just keep one variable(pretty important one) at constant.
you still need to make other variables constant, like the time between pulling and clamping off.

SW Stringer 05-16-2008 11:06 AM

Quote:

Originally Posted by rscottdds (Post 2338985)
And I realize this. However I have a very accurate measuring devise and when I pull with a lockout machine, I can get differences with each pull. I assume with a CP machine these differences would be minimized. Does this translate to a difference on the court for a college level player and above? I'm wondering if it is worth it to change to a CP machine (ie buy something like a wise)
-Robert

Published accuracy on the Wise is plus or minus half a pound, on the Babolat's its plus minus 100 grams. However it's been noted on the GSS site that many of the electric/electronic tension heads overshoot by quite a bit (up to 5 lbs), but the Bab's appear to be critically damped and don't overshoot by much. If your electronic measuring device can't capture peak pulling tension then you may not even see it - I don't think even the $40 fish scale that GSS sells can "capture" quick transients. That (transient capture) requires a fast acting lab grade transducer/controller. And certainly the spring based tension checkers are neither accurate (compared to the resolution of the digital units) nor able to show transients. But YU is correct, accuracy is in the heholder's eye.

YULitle 05-16-2008 11:23 AM

I wanted to slarify what SW Stringer said, when the Babolats overshoots the tension, it settles back on the correct tension immediately after.

barry 05-16-2008 01:04 PM

Quote:

Originally Posted by YULitle (Post 2339982)
I wanted to slarify what SW Stringer said, when the Babolats overshoots the tension, it settles back on the correct tension immediately after.

So what is the difference between overshoot and pre-stretch? On my machine, when pre-set is on, the tension goes to the percent of pre-stretch + tension, then settle back to the tension. If you turn pre-stretch off, then it pulls and holds the desired tension.
On my drop weight machine, it pulls and holds the desired tension. The crank varies by as much as 5 pounds, depending how fast you turn the crank. If you crank it slowly, it is within 1 to 2 pounds of the tension.

Drop weights are by far the most accurate tensioner.

YULitle 05-16-2008 01:19 PM

Quote:

Originally Posted by barry (Post 2340271)
So what is the difference between overshoot and pre-stretch? On my machine, when pre-set is on, the tension goes to the percent of pre-stretch + tension, then settle back to the tension. If you turn pre-stretch off, then it pulls and holds the desired tension.
On my drop weight machine, it pulls and holds the desired tension. The crank varies by as much as 5 pounds, depending how fast you turn the crank. If you crank it slowly, it is within 1 to 2 pounds of the tension.

Drop weights are by far the most accurate tensioner.

The difference, I would guess, is intention. The overshooting of tension is not a desired trait, for some stringers.

SW Stringer 05-16-2008 03:50 PM

Quote:

Originally Posted by barry (Post 2340271)
So what is the difference between overshoot and pre-stretch? On my machine, when pre-set is on, the tension goes to the percent of pre-stretch + tension, then settle back to the tension. If you turn pre-stretch off, then it pulls and holds the desired tension.
On my drop weight machine, it pulls and holds the desired tension. The crank varies by as much as 5 pounds, depending how fast you turn the crank. If you crank it slowly, it is within 1 to 2 pounds of the tension.

Drop weights are by far the most accurate tensioner.

I agree, dw's are the most accurate and if used gently will NEVER overshoot. On the electric/electronic CP's every time it repulls it will overshoot some or alot (depending on the model) so if you're clamping off when it's at 5 lbs overtension - that's what you get - so how do you know what the tension is when you clamp off? Ans. you don't - it could be anywhere from REF Tension minus the repull hysteresis to the REF tension plus the overshoot - and that could be a 5.5 pound or more range. Again the repull trigger point and overshoot amount depend on the machine and the manufacturer - and most likely not even published. The user has no say in this matter. At least with the DW's and cranks the user is in direct control of the clamp-off tension.

rjkardo 05-19-2008 10:31 AM

Quote:

Originally Posted by rscottdds (Post 2338273)
Are constant pull machines better than cranks as far as racquet playability is concerned? I know consistency is the name of the game, and if you can string a racquet the same every time it doesn't mater what kind of a machine you use. However it would seem easier to get a consistent string bed with a constant pull machine. Is this true? And if so does it really matter? Can the above average player tell the difference as far as playability is concerned if you indeed get a more consistent string bed?
-Robert

To answer your first question... no.

2nd question... No. And it does not matter anyway.

Last question...No.

Rodjk #613

abllee2198 05-19-2008 11:57 AM

Constant Pull Vs Crank
 
rscottdds: The best answer is, "It depends." It depends on the constant pull, it depends on the crank, and most of all it depends on the stringer.

So if you'd like to be more specific, then perhaps you will get a better answer. So, which crank and which constant pull?

Albert

fastdunn 05-19-2008 12:37 PM

I agree dropweight is just about the most accurate in terms of tension itself but sometimes I do single pull, sometimes double or even triple pull where main inconsistency of drop weight stems from, IMHO.

rscottdds 05-19-2008 02:31 PM

Oops, I forgot I even posted this question :-). The crank is on a Gamma 5003 and the CP I was talking about was the Wise. When I use the lock-out and the digital scale I can pull a few lbs different on each pull, and it drops by a quarter or half a pound every few seconds until it levels out.

I've seen video of a digital scale on a Wise and it pulls then stays very consistent (ie the tension doesn't drop). So my questions were if this tension difference really matters and if so would getting a Wise help? I understand that if I use a lock-out and it locks out at a certain value then starts to drop by a consistent amount, then if I clamp at the same time after lockout every time then I should get a consistent result. It would just seem that if you take away as many variables as possible that you would get better results.

Wow, I just reread what I wrote. Hope itís understandable :-)

-Robert

LttlElvis 05-19-2008 03:13 PM

Robert,

I am not sure if I am answering your questions but I think I have about as close a situation to what you want. I have a Gamma 6004 and a Wise. I can tell the difference in the sound of the string bed and feel of my racquets when I use a crank. I used to tend to have a favorite racquet.

When I switched to the Wise, the sound of the string bed and feel of my racquets are identical. No more favorite racquets, and I just use them on a daily rotation to get even wear ( I use gut). By the way, I am a dentist too, so I am very anal about every little thing. The best thing about the Wise is the consistency.

jim e 05-19-2008 05:09 PM

Quote:

Originally Posted by LttlElvis (Post 2350228)
Robert,

I am not sure if I am answering your questions but I think I have about as close a situation to what you want. I have a Gamma 6004 and a Wise. I can tell the difference in the sound of the string bed and feel of my racquets when I use a crank. I used to tend to have a favorite racquet.

When I switched to the Wise, the sound of the string bed and feel of my racquets are identical. No more favorite racquets, and I just use them on a daily rotation to get even wear ( I use gut). By the way, I am a dentist too, so I am very anal about every little thing. The best thing about the Wise is the consistency.

Hi LittlElvis: I use a constant pull machine as well,(not the wise), just to have more consistancy in the process.Three of my racquets are all gut, and feel the same,(4th gets changed a little to try out different strings).BTW I am a dentist too.(Ohio State, 1980).I am not a string breaker,and got a great # of hours out of 1 racquet, now like you I rotate between them so they all feel the same.Seems that consistancy is the name of the game, and although it is said you can get consistant results with both, I believe it is easier accomplished with a constant pull.


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