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Old 05-16-2008, 03:50 PM   #13
SW Stringer
Join Date: Mar 2004
Posts: 621

Originally Posted by barry View Post
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.
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