I input the butt & tip diameters and then the amount of spaces but I never get the same length as my measured length. How is my wrap supposed to close if I can't get the same length from VIZ-Wrap?

Check out Visual Weave and Visual Wrap Forum:
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lots of help and how to's

The vw calculates the length for you. If you have compressed or elongated spacing that will determine the length of the wrap

Freddwhy (Rapt-Ryte)

I understand it calculates the length but the vw length is not gonna be where I measured the diameter of the blank.

Vizwrap calculates spacing based on the assumption of a square pattern. If you estimate where you want your pattern to start and finish and put those measurements into the Taper View screen then it will look at the number of repeats you selected, work out the diameter at the middle of the wrap (by averaging the butt and tip diameters), and then work out the length of the wrap by multiplying the centre circumference by the number of repeats. So unless the length you selected to start with is a multiple of the centre circumference then the vizwrap calculated length will always differ.

It is an iterative process. You estimate the length, take your measurements, put them into the software, and it calculates a new length which is likely to be slightly longer or shorter. Using this new length, take your measurements again, put them into the software and confirm the calculated length does not change markedly. If the taper of the rod is not radical then the change should be minimal.

Regards
Dave Boyle
www.threadcentral.net

As long as the length is somewhat close to what you measured you are fine. If you measured at 200mm, and VW says 220 that is OK.