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View Full Version : Why does it matter where the tension head starts to pull?


pmata814
01-10-2007, 10:21 AM
Why does it matter where the tension head, on a crank, starts to pull? I've read some posts here saying that in order to achieve consistent results, on a crank machine, you must try to start the tension head in the same place for each string. But what I don't understand is...if the spring is meant to lock-out when the refrence tension is reached, why does it matter where the tension head starts or ends? If it locked out it means the desired tension has been reached, doesn't it...regardless of where the tension head started or ended?

Kevo
01-10-2007, 02:58 PM
My guess is that people are concerned with the length of the tensioned segment being inconsistent. As soon as the machine locks the string will start to relax and lose tension. Then you clamp the string inside the frame, and now only the frame segment is losing tension. If you have varied lengths of tension string before clamping, you will lose different amounts of tension before clamping the segment of string that is inside the frame. Therefore, each string could have different tension. There is a similar argument to be made for trying to pull tension at a consistent speed as well.

LoveThisGame
01-10-2007, 04:22 PM
There are three factors:

consistency on position of the tensioning head

comes consistency on time and speed to clamp off.

pmata814
01-11-2007, 06:03 AM
Thank you for the replies. I appreciate it.

Netgame
01-12-2007, 03:56 PM
As soon as the machine locks the string will start to relax and lose tension. Then you clamp the string inside the frame, and now only the frame segment is losing tension. If you have varied lengths of tension string before clamping, you will lose different amounts of tension before clamping the segment of string that is inside the frame. Therefore, each string could have different tension. There is a similar argument to be made for trying to pull tension at a consistent speed as well.

When the string starts to relax, how many lbs. of tension can be lost if you don't clamp in time? Does this mean that string tensions cannot be accurate with a crank unless you clamp immediately?

LttlElvis
01-13-2007, 04:42 PM
When the string starts to relax, how many lbs. of tension can be lost if you don't clamp in time? Does this mean that string tensions cannot be accurate with a crank unless you clamp immediately?

This really varies among string to string. My guess is once the string reaches tension, most of us clamp off within 4 seconds so we really don't lose that much tension.

However, as an experiment, get a digital fish scale ($15), tension a string and hold it. With a digital readout, it is easier to see the tension loss and at what speed. You will be amazed at the amount of loss and how quickly, depending on type of string.

EricW
01-13-2007, 08:48 PM
This really varies among string to string. My guess is once the string reaches tension, most of us clamp off within 4 seconds so we really don't lose that much tension.

However, as an experiment, get a digital fish scale ($15), tension a string and hold it. With a digital readout, it is easier to see the tension loss and at what speed. You will be amazed at the amount of loss and how quickly, depending on type of string.

digital fish scale?

edit: i googled, it, but how would you use it to check tension? I undserstand the concept but how do you do it, exactly?

Hey, Moe!
01-13-2007, 09:31 PM
If you are an experienced stringer, it is likely that you will tension the string at about the same place, out of habit. It is just something that I do, without thinking. The tension head grabs the string at about the same distince from the frame, no matter what. It's just how I string.

And, if you are paying attention, you would clamp it within a few seconds.

Within that level of tolerance, I really can't see a problem.

LoveThisGame
01-14-2007, 04:55 PM
"likely that you will tension the string at about the same place, out of habit"

True. It's unlikely to fiddle with positioning, but could happen on occasion.

---------------

"And, if you are paying attention, you would clamp it within a few seconds."

More variability possible. Darn clamp doesn't move to the new spot as quickly this time. Gee, did that string slip in the clamp? Oh! Oh! It looks like the clamp is slipping on the glide bar. Oops, gotta sneeze. Phooey, there goes the phone. Just woke up from thinking about something else. There's someone yelling to me; what did they say? Oh boy, I gotta take a pee ... right NOW. Darn, there goes the cat with the string in its mouth.

Then there's: On a crank machine, do you pull the tension consistently at the same speed.


Lot of nit picking, but ...