Linear gripper verses the Rotational string gripper

Discussion in 'Stringing Techniques / Stringing Machines' started by barry, Aug 13, 2005.

  1. barry

    barry Hall of Fame

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    Has anyone used both a linear gripper and a Rotational gripper? A friend has an Alpha Revolution electronic machine and he says he likes the Rotational gripper better and recommended getting an electric machine with the Rotational gripper rather than the Wise.
    I have always used a linear ball bearing gripper, and have no experience with the Rotational ones. Read where the linear ones are superior, but this day and age who knows.
     
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  2. theace21

    theace21 Hall of Fame

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    I don't know of anyone that has used both that prefers a rotational gripper...
     
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  3. Gaines Hillix

    Gaines Hillix Hall of Fame

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    There are many factors to consider other than just the type of gripper itself. I haven't heard of complaints about the ability to hold the string with rotating grippers on electric machines. Most rotating grippers take more string because the string has to be wrapped around the tension head to get to the jaws(the exception is on the SP Aria and TopSpin machines). IMO, one would be quicker stringing with a linear gripper than a rotating one because of that extra second or so that it takes to wrap the string around the drum. Some rotating heads are also slower, which may or may not matter to you. There may be differences in the motor and tension control mechanisms. All of the machines with rotating heads don't use the same controls. The Wise head is pretty accurate. It pulls to within .1 lb of reference tension every time and it only takes a .5 lb. tension drop for it to repull. If the machine with the rotating gripper uses a spring instead of a load cell it would take a much larger tension drop to trigger it to repull. If you already have a crank machine that you like the Wise is a no brainer, IMO. If you don't have a machine the decision would be tougher. Of course, it depends on your budget too. Noo news to you, but one can buy a new crank machine and add the Wise head for less than an SP Aria or Orbitor Revolution costs and have two tension heads with one that can be used where power is not available. Just my $.02 .
     
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  4. barry

    barry Hall of Fame

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    Thanks for the Information.

    Still looking for the ultimate machine. I have a budget of $1000. The Wise is $550 and that does not leave much for the stringer! The Smart 6000 cost $1000 and is a complete unit, but it is a stand model. So my decision is what can I purchase in a table top for $1000 or less with an electric tensioner. There are some available in that range, but have zero experience with them. Eagnas 865 claims constant pull but after watching the SPtennis site videos of a Neon CX, who knows for sure.
    So back to square 1. The Eagnas 840 and a Wise for $1000 or a damaged Revo 4000 for $400 or so off the auction site. Either way, I think the Wise is the best option.
    Wise should be shot for putting the video on their site; many potential customers like me are hooked!
     
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  5. diredesire

    diredesire Super Moderator

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    haha, that's funny since i just watched it a short while ago. I thought it was cheesy, but very cool.

    As far as grippers go, like Gaines said there are a few issues to consider. My main concern with rotational grippers is that they take more string because you (typically) have to wrap the string around the drum. Linear grippers you just drop it in and go.

    If you want to try that eagnas machine, as i know you feel secure with the company, i think the "constant pull" issue is less of a big deal than you think. It's not performing like a crank/lockout machine, it just takes a longer time to compensate for the tension loss. It's still more or less a "constant pull," although of course, not as accurate/consistent.

    The wise head looks to be a killer upgrade, but of course, you're going to pay that EXTRA money for it, consider it an add-on, because it's not like the crank heads that come with machines are useless. It really should be considered an extra tensioner, you could alwayas buy the crank and string for customers 'til you make the extra money then buy the wise head then.
     
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  6. Gaines Hillix

    Gaines Hillix Hall of Fame

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    I would just as soon have a crank machine as an electric machine with a low tech tensioning mechanism, linear or rotating. By low tech, I mean one that uses a spring to detect if the set tension is reached. Once the set tension is reached, they stop pulling until a relatively large drop in tension occurs. It takes several seconds for the tension to have dropped enough for the machine to detect it and repull. By that time you will probably have clamped off.
     
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  7. barry

    barry Hall of Fame

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    I think Wise did a very good job on the implementation and the video demonstrates the features. Overall whoever designed the Wise, has probably strung a few rackets. It looks like a solution to modernizing crank machines. In my case, it looks like a nice way to get a quality electronic tension head at a small price.
    I do not own stock in any of the stringing machine companies, but have yet to see a post on the Eagnas 865. Strinforum had review on the 845, which looks like it has the same motor. Hopefully they have sold one or two!
    Or like you said, I could buy the crank and upgrade later. To bad we do not have machine shows, like Comdex for computers, where we can go and play with the products.
    Decsions, Decisions.
     
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  8. barry

    barry Hall of Fame

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    Good point! All I have to do is find out if the 865 uses a spring to detect the tension. I would probably guess yes, but will pose the question to Eagnas.
     
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  9. wonder_wall

    wonder_wall Rookie

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    I think it's interesting to start a discussion like this by looking at the worst example of the type. There are a few known drawbacks to the "e.stringer"'s mechanism that are clearly visible and that people have mentioned:

    (1) More annoying both in string insertion as well as string removal. The "e.stringer" involves looping twice around the head then running the string through the middle section. This seems like something I'd rather not have to "get used to." To me this seems the worst issue.

    (2) Made of plastic and the plastic gets notched over time. Probably not a huge deal, but sounds like over time this would add more to the annoyance factor.

    (3) Need to cut a little longer piece of string. I'd guess and say maybe 6" more. Probably not a big deal.

    (4) Bends up the string, some think a little harder on the string. I tend to doubt this.

    The Silent Partner DG gets rid of (2) because it's made of metal.

    The Silent Partner Aria gets rid of (1) (2) and (3)! It is a best of both worlds approach and a rotational puller that I think looks great.

    So rotational pullers are not all equal.

    I continue to think the Silent Partner Aria is pretty much the ultimate machine for the home stringer, like versus a Wise:

    - 360 degree movement
    - Very quiet and FAST tension puller. Aria could be operated with the kids sleeping. Wise is very noisy, probably especially so at night-time low-noise levels.
    - Nice suspension racket support system, minimized hole blockage and maximized racket protection and faster mounting.
    - Table-top OR floor-stand operation out of the box. Best of both worlds and table operation frequently REQUIRED by the home stringer.
    - Updated three tooth clamp heads to make stringing easier, of very high quality according to USRSA evaluation.

    The DG has the same exact racket support system, the older style 5-teeth clamp heads and not as sophisticated of an electronic mechanism, but is still verified accurate *and sensitive* constant pull by the USRSA.

    DG seems like a very nice machine, and at 1k certainly has if nothing else a much better racket support system than something like a Revo + Wise, and the Revo plus Wise costs more.

    I can think of one advantage for the Wise versus the DG though - seems to be shop-oriented, built to last, fairly battle-proven. Seems to go and go without problems, whereas the DG is less a known quantity. Not to say it's worse, but there's just not that many people posting in these various online places that use it.

    These Wise advantages don't seem to be present against the Aria though, since its tension puller (as well as racket support system, turntable, everything but clamps and stand) was used at the recent Nasdaq 100, and shop owner David Pavlich, a pretty smart guy and also owner of a Babolat Sensor, owns one as well, so I wouldn't worry much about that model. But the DG doesn't seem to get that much attention (perhaps one reason being lots of Revo + Wise pumping around here), so less of a known quantity from what I can see.
     
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  10. barry

    barry Hall of Fame

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    Thanks for the Info, I will have to send them an Email on the DG model, it looks like it could be converted to a table top, picture has feet on the base. It is right in the $1000 price range.
    Enjoyed watching the Sptennis videos, understand LF might be adding video to their web site. For those of us who do not have access, it would be interesting to see how they work.
     
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  11. wonder_wall

    wonder_wall Rookie

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    About the DG, yes that's right. I meant to mention of all the advantages listed for the Aria, the DG shares many, including the nice racket support system, 360 degree movement, AND the table-top OR floor-stand operation out of the box.

    So that last item is definitely one of its strengths. The DG and Aria are the only machines I've heard of that work out of the box either on a table-top or on a floor stand. Very nice thinking from Silent Partner, certainly for the home stringer at least a big plus.
     
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  12. Gaines Hillix

    Gaines Hillix Hall of Fame

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    Agreed on the DG and Aria. I'd want to clarify how they detect when the set tension is reached and also how they detect drops in tension and how much tension has to be lost before they repull. This seems to be one of the real keys to accuracy on electric tension heads.
     
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  13. Two Fister

    Two Fister Rookie

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    Not so sure this is always true. I had a Gamma Progression ESII+ that apparently uses a mechanical system to detect tension drop before repulling, and according to Gamma (my phone conversation with their tech support), when it reaches the reference tension, you hear a click, and everytime it repulls to the reference tension, you hear a click. Well, after the first click, many times it takes less than a second before you hear the second click. And it usually clicks about 3 or 4 times before I can clamp off the string. (As a reference, I string a puredrive in about 20 minutes).

    According to the Gamma Tech on this site, the drop in tension before repull on a Progression ES is 2 to 4 lbs. On their high end microprocessor machines it is .5 to 2 lbs.

    BTW, I really like my Silent Partner Aria.
     
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  14. Gaines Hillix

    Gaines Hillix Hall of Fame

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    Agree, not all machines are the same, but these specs aren't posted anywhere on the websites. They post a lot of other specs., but not how sensitive their tension heads are. I read on the Silent Partner site that some machines require up to a 15 lb. drop before they repull. Even 4 lbs. seems like a lot to me. That could introduce a lot of different tensions into the stringbed. So, I am just saying that buyers should check this spec. with the seller before purchasing.
     
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  15. wonder_wall

    wonder_wall Rookie

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    The DG has nothing like a 4 lb variance, this is already well known.

    The Aria uses the common "high end" implementation, load cell monitored by microprocessor, based on what I've seen I'd say it's a good bet it may well be a little more sensitive than the Wise. I say that just because it seems like a slicker implementation where the Wise sounds just slightly clunky - noisy and having a 1/2 lb tolerance.

    The DG has a microprocessor-monitored implementation, but I don't think it's monitoring a load cell. I'm not sure where exactly the microprocessor gets its info on string tension, but it is a microprocessor-monitored implementation.

    It also has knot overtension, prestretch modes, etc. just like all the "real electronic" machines (I know Eagnas claims their $200 stringer is electronic, which is obviously some kind of bull).

    And as I said the DG has been evaluated as *sensitive* by the USRSA, who said the following:

    "We then checked the constant pull tensioning. Some machines will say they are constant pull, but don't actually pull again until the string has lost several pounds or more of tension. The DG recognized tension changes right away and compensated."

    While "right away" is not very precisely quantitative, I'd gather it at the very least means less than a pound of variance.

    Also, there's a video on s p t e n n i s . c o m of the pulling action of the DG, showing a close-up of the string *continuously* moving, shown by a mark on the string, so it seems to be quite sensitive as the USRSA says and it's definitely not in the league of the more inexpensive electrics, like Gamma, Eagnas, e.stringer et. al. And again, in terms of features, its the same as the Aria (knot overtension, prestretch pull mode, etc.).
     
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  16. Gaines Hillix

    Gaines Hillix Hall of Fame

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    I was referring to the Gamma machine referred to by another poster when I said 4 lbs. of tension had to be lost before it repulled. As the USRSA said, this really isn't true constant pull like some of the other machines, including the Wise. It begins repulling very quickly. Only .5 of tension has to be lost before it repulls. The Physics and Technology of Tennis book has a chart showing the rate of tension loss after clamp off. String will lose more than a lb. of tension is less than 1 sec. after the head stops pulling or the string is clamped off. My point is that this information is not that easy to get from the manufacturer's websites. The Wise information comes from their patent application.
     
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