String Tension Disparity

[Kelvin]

I've been doing some reading and came upon this little article to give some explanation on possible reasons for disparity in string tension, between the electronic constant pull machines, and the hand crank spring lock machines...


"Insights from Alber Lee, an USRSA Certified Racquet Technician (CRT), about why there are tension differences in the string bed between electronic constant pull machines versus hand crank lock out spring type machines:

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The clamps in most spring machines are terrible and the play in the guide rails is so much as to be the primary reason there's such a large disparity between the machine types. I know this because I used to string on a Ektelon H and build modifications for the guide rails to eliminate the play. With that one change, that Ektelon now strings as tight as a constant pull machine. Note: There are electronic and non-electronic constant pull machines. The Century SP-11 (made by Major Sports of France) uses a spring type constant pull mechanism.
Differing pull or hand crank rates.
Quality of clamps. Generally constant pull machines use higher quality diamond dusted clamps. So clamp slippage is another reason.
Generally poor calibration or lack of calibration is the last reason I can think of for why there's a 10% disparity between spring and constant pull.

Note: Constant Pull pulls until it reaches to desired tension then stops pulling until some difference tension is detected, then corrects the tension by pulling further. Now in most instances any good stringer has already clamped off before the correction occurs. The small window for many machines is on the order of 100 grams. As soon as your machine sees a 100 gm difference, it makes a correction.

Albert"

Yes my shoulder is feeling better for those of you wonder, thank you for your support :) I appreciate it.

I've been looking for a stringing machine lately, and am doing some research on what features are beneficial and what aren't...
Some opinions that I've come across have heavy biases towards electronic machines, when I've read from some of you that the drop weight machines, are just as good, if not better in the quality of string job.
(Stringers experience, and knowledge set aside of course.)

I will continue with an add on to this, as this subject is quite intriguing to me.
My current budget is $500, because I anticipate doing a fair bit of stringing, and gaining more experience.
Thanks to all of you who have posted some techniques, and input about this subject, I really do appreciate it.

-Kelvin

[Kelvin]

My opinion about the electronic stringing machines is that it seems that they are here, to possibly speed up the stringing process, however... IMO they cover up a lot of human mistakes, and slopiness.
I'm not saying they are bad, but then I've read an arguement stating that the drop weight machine is not quite as accurate as we think they are...
Now how is this really possible?
I understand that if the bar does not rest horizontally that there could be variations in string tension upwards of 10lbs???
Yet I read here, that you guys are able to string more accurately, and tighter than those hand crank spring locking machines...

Which really is more comfortable to string with?
Or is this again a matter of personal preference.
I've changed my mind 3 times between the different types within 24 hours, and now my budget is for $1000 USD... I'm hoping to actually save some money, by purchasing either the spring lock, or the drop weight machines, as cooler has been able to achieve superb results.
I also notice that Cheung is using a drop weight machine.
I'm not sure what you're using right now Kwun, but it seems you were using a spring locking machine... and Eagnus seems to post all their feedback from their customers hehe.

"I purchased a hawk 80 from you. Just got it yesterday, thanks.

K. Han, U.S.A., December 29, 1998"

Anywho... if you guys could help me out on this topic, it would be greatly appreciated.
Also gives me something to do the next time I injure myself... to string racquets :)

Here is a small list of features that I've compiled that indicate a more favorable machine over another..:

1. Six support mounting points for the racquet head. Generally, the more support points on the head, the better the head is supported from the stress during the stringing process.
2. 360 degrees rotatable table where the head is mounted.
3. Brakes for the table. (no these are not for speeding... when driving too fast)
4. Adjustable table height for floor standing models.
5. Fixed clamps are better than floating clamps since the support system loses less tension when you clamp off the strings.
6. Clamps which have diamond dust coating grip the strings with less force than those clamps without the diamond dust coating. Slippage is obsolete hence the tension is truer. The clamps are probably the most important part along with the tension head/mechanism for a stringing machine.

I'm sure there are more desirable characteristics or features, but I guess this list will do for now, until I can learn more about the stringing dynamics. Since Kwun helped explain the stringing process already (much appreciated), I guess it just leaves for me to decide if it's worth the money to pay for a more expensive machine...

I realize that doing things the manual way has a learning curve, like anything else out there, and I'm thinking that in the long run I may benefit more from doing things the old fashioned way, and getting them done properly.

I realize there are electronic machines out there selling for under $1000 US, but I guess I'm just trying to maximize my dollar value for choosing a machine.

My last question... what if any opinions have any of you formed about your respective string machine manufacturers???
My old coach Lee stated that he thinks that the Ektelon Model H (which has since been discontinued, but is the most popular stringing machine ever made), is probably the best one there is.
How about the rest of you???
What machine are you using? and how satisfied are you with the overall deal you got?

If I can't decide I may as well just find a second hand model, that's got every feature possible... :(
Thanks for your replies.
-Kelvin

[kwun]

hey. that could be "Kevin Han". but i am sure he probably has other people string his rackets for him though.

anyway, i don't own a machine anymore. i had a hawk80 which i sold couple of weeks ago. with my dumb finger it takes me nearly 45mins each racket. and it was a drop weight machine, so it was quite tedious to have to reclamp and reclamp. that's the good thing about electronic and crank machines, you clamp once and that's it.

the tension variation for the drop weight is not that much. with some practice, i can pretty much get the weight to +/- 5 degree from horizontal. and if you think about it, the error is proportional to the cosine of the error angle. and the cosine function is pretty flat at +/- 5 degrees.

if your budget is so high at US$1k, you should be able to get a really nice crank machine, or a cheapo electronic. don't get a drop weight, you'd regret it.

a friend of mine just bought an Alpha Revo 3000. crank, 4 supports, swivel clamps. i believe non-swivel type stationary clamps are faster since you only need to tighten up one thing per clamp. for swivel clamps, you need to tighten two things per clamp.

he just received the machine when i visited him. he was a very happy man.

anyway, i suggest you get a nice crank machine. learn it the harder way. and when you get better at it, you will start needing to fine adjust the tension while stringing, and twisting a knob is much easier than dialing into a number pad...

[TrunkZ69]

whats the difference betweeen ad crank and a drop weight machine, could you give me like examples?

[Kenny]

Visit the site www.sptennis.com, there is a thorough explanation
about the different types of machines.

[Kenny]

Visit the site www.eagnas.com, there is a comparison chart between different makes of machines and models.

[bigredlemon]

That was an interesting read. Since nothing like this has been mentioned before in that depth, i think it's time for a bump.

Btw, what's a quick an easy way to tell what type of stringing machine you are looking at? (Aside from asking the stringer of course)

[Winex West Can]

Originally posted by bigredlemon

Btw, what's a quick an easy way to tell what type of stringing machine you are looking at? (Aside from asking the stringer of course)

Look at the machine. You should be able to tell whether it is a drop weight, crank or electronic machine easily.

Then, you have your flying clamps, fixed and swivel clamps.

For the support system, it is usually 2 pt, 4 pts and 6 pts.
2 pts = one support each at the 12 and 6 o'clock position.
4 pts = one support at the 6 o'clock and 3 support points at 11, 12 & 1 o'clock
6 pts = 3 support points at 11, 12 & 1 plus 3 support points at 5, 6 & 7 o'clock.

Some pics follows. First one is a 2 pt, flying clamp and drop weight (probably the cheapest of the lot).

[Winex West Can]

Second one is 2pt with swivel clamp and electronic pull

[Winex West Can]

4 points, fixed clamps and crank

[Winex West Can]

6 pt, fixed and drop weight.

You can now imagine the various combinations of 2 pts, fixed, crank; 2 pts, swivel, drop weight, etc. You also have portable (1st pic), table top and standing versions

BTW, all the pics are taken from www.eagnas.com (I'm not a customer nor affilated with them).

[bigredlemon]

Thanks.

I've seen one in which there is a rod shaft around which there is a spring behind a pullable knob that slides along that rod. You pull the knob+slider down the rod while compressing the spring until the desired tension is reached. This has the simultaneous effect of pulling the string along the rod.

Any idea what type of machine that is?

[jump_smash]

Originally posted by Winex West Can
4 points, fixed clamps and crank

Yes, but would be better to call this a spring tension, as that is how the tension is delivered (as opposed to a weight or drop weight machine).


Regards

Stuart

[Rohly]

How long did it take for you to learn to string racquets? Is it difficult?

[Rohly]

Also if you bought a stringing machine would you have to buy a full set of tools to go with it?

[LazyBuddy]

Rohly,

String a racket might be very easy to understand (watching others, reading user guide, etc), however, it might take several trials to get the "feeling" to be more accurate, effective and fast.

My own experience tells me that it's better to use a cheap racket and some junk strings to do some demo runs before working on pricy rackets. Also, starting with lower tension might be a bonus as well.

For the tool set, many machines come with the basic tool set. You need to read or contact them for detail. If u happen to need some additional tools (i.e. an extra flying clamp, owl, etc), u need to consider that within ur budget as well.

[Winex West Can]

Originally posted by bigredlemon
Thanks.

I've seen one in which there is a rod shaft around which there is a spring behind a pullable knob that slides along that rod. You pull the knob+slider down the rod while compressing the spring until the desired tension is reached. This has the simultaneous effect of pulling the string along the rod.

Any idea what type of machine that is?

It would be a spring-based system similar to the crank as Jump_Smash suggested. Have never seen one of those before.

[Rohly]

I do not know how to post an image but what is your opinion on the yellow stringing machine in the first picture posted by winex west can?