|08-05-2008, 08:41 PM||#1|
Join Date: Oct 2007
Location: Caught in No Man's Land
Mansewerz's Guide to Buying Stringing Machines
The following post is strictly my opinion. I will try to remain as objective as I can and become subjective when necessary. These are not the ultimate authority on any subject.
Do I need a stringing machine?
If you belong to any, but not limited to just one, of the following groups, then you may need a stringing machine.
Now if you need a stringer, continue reading. If you don't, but you still would like to learn about stringers, continue reading. If you don't need a stringer and you're done learning about stringing machines, feel free to close this thread and do as you please.
Types of stringing machines (Grouped by tensioners)
Dropweights- Dropweights are tensioners that utilize gravity to tension a string. A weight is positioned on a rod connected to the machine according to tension, and "dropped" (the weight and bar should be allowed and assisted to fall down slowly and gently). Basic laws of physics apply here. If the bar drops and stops at a horizontal (parallel the floor) position, the string is tension to the desired weight, and the string should be clamped off, and then one goes on to tension the next string. If the bar does not fall to a parallel position, then the bar is lifted so that the grippers disengage, and let go of the string. Then you adjust the amount of slack of the string, put it back into the string gripper, and once again "drop" the dropweight. Repeat until horizontal. If the bar is above horizontal, give more slack. If below, give less slack.
Some machines have a clutch mechanism (usually ratchet, or just silent like the Silent Partner dropweights) that allow the stringer to hold the tensioning drum, and lift the bar a little bit, and re-drop so to see if the bar will fall to parallel. Clutch mechanisms are designed so that the operator doesn't have to release the string and feed more or less slack. In a way, it helps lessen the workload of the operator in tensioning (especially for stringers that are just starting out. But hey, I always use my clutch, and i've strung on my machine for a while now.) This is only used when the bar falls below parallel. If it falls above parallel, adjust the slack, re-drop, and go on from there.
Dropweights are usually the slowest type of tensioner, hence the reason why most basic machines are dropweights. Also, dropweights are pretty simple to use, and with practice, they can become a fast method for tensioning. The system itself is pretty simple as well. It's pretty much a lever with a weight. No locking mechanisms or complicated springs.
Never, I repeat, never under any circumstances, force the bar down farther than it will freely go. Doing so can damage the string and the racquet, and, in some cases, forcing the bar can damage the machine. Also, the desired tension will not be reached. It will be much greater than the set tension.
Cranks-Cranks, aka Lockout machines, are a tensioning mechanism that uses a pre-loaded spring to determine when proper tension is reached. There is a crank, that has a built in brake/locking mechanism. The stringer turns the crank until the tension is reached, then the brake is engaged and no longer allows the stringer to turn the crank, and then that string being tensioned is clamped off. The stringer then disengages the brake and tensions the next string.
The mechanism is known as a "lockout" mechanism, which is why cranks are also known as "lockout" machines. Cranks are typically the fastest tensioner, but require more physical work than electronics or automatic dropweights. Note: When I say faster, I mean that they are able to tension strings more quickly. You should not turn the crank at full speed to quickly tension the string. A slow, consistent speed gives the most accurate results.
Electronic tensioners-These are the high end tensioners that use a motor/microprocessor to tension a string. Pretty simple to use. Hit the button, the string is tensioned. Hit the button again, go tension the next string.
Important Note: There is a difference between "electric" tensioners and tensioners controlled by the use of electronics, or an electronic tensioner for short. Simple electric tensioners work in a fashion similar to lockout machines. A preloaded reference spring is used to get the tensioner to stop pulling. Electronic tensioners use sophisticated, high end control electronics to sense a change in tension/load and adjust to those changes. This helps keep a "true", steady reference tension in each string. Lower end, electric machines typically don't sense these changes in loads, and if they do, they do it in a relatively poor manner. The lower end electric machines will typically be cheaper than the electronic machines.
Electronic tensioners are rather fast, not quite on par with cranks, but they can be easier to use. Also, keep in mind that some electronic tensioners can be very slow to pull to refernce tension.
Automatic dropweights-These are a rather new tensioning mechanism that utilizes a dropweight to tension a string, but unlike ordinary dropweights, as long as these don't fall all the way and bottom out, the angle of the tension rod/arm is irrelevant because proper tension will always be pulled. Auto dropweights have a special design that maintains the length of the string relative to the angle of the pull. This allows for this "any angle" constant pull. Today, only Laserfibre and Stringway produce machines utilizing this type of tensioner. Revolutionary? You decide.
Automatic dropweights are much faster than regular dropweights. They can tension a string just as fast as a crank tensioner, but the fact that the weight has to be lifted back up to release the string after clamping causes it to be slower than a crank overall. However, it can still be a very fast type of tensioner.
Constant Pull v.s. Lockout-Constant pull machines are machines whose tensioner pulls tension until proper tension is reached and continues to pull tension. The purpose of the constant pull is to maintain accurate tension in a string. It helps create a more consistent stringbed. Lockout machines are those that utilize a preloaded spring to stop the tensioner from continuing to pull tension and stop pulling tension once proper tension is reached.
*A machine that uses constant tends to string a tighter than a machine that uses lockout technology. Likewise, it is vice versa for lockouts. If you ordinarily get your racquet strung with a lockout, then it is probably 5-10 % looser than if it was strung with a constant pull machine. Adjust accordingly when getting your racquet strung. This is a basic rule of thumb, and the reasons for it are complicated and I'd rather not explain it here. *
Machines that use constant pull
Machines that use lockout technology
A quick note regarding lockout v.s. constant pull. If you're getting an electric/electronic machine, in my opinion, don't get one that uses lockout technology. It is just the same as a crank, but with a motor doing the cranking for you. (In essence).
The crank will typically be cheaper than the lockout electric machine. The best way to tell if an electric machine is lockout v.s. constant pull is to check the description of the machine, or better yet, talk to the company's "Machine guy", for lack of a better word.
It's typically user preference when selecting between an electric (lockout technology) and a crank. An electric can, theoretically, be more consistent by removing human error in tensioning, especially if you're getting lazy at the end of a long day of stringing.
More to come in following posts.
Gameplan: Get it deep, wait for the short ball, then come in.
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Last edited by Mansewerz; 12-27-2008 at 02:38 PM. Reason: Revisions
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