I'm trying my first closed wrap and am unsure of my layout. I've tried figuring the offset layout per Clemens but have no idea how to get the 90/270 numbers correct. My measurements are; butt end circumfrence is 40.5mm with five planned patterns, making a total distance of 202.5. My taper at the 202.5 is 36.20 mm. I've heard one method is to average the two circumfrences and make that my spacing. But when I do that the length shortens by 11mm. Not sure where I'm going wrong? Any help would be greatly appreciatged. Is one method better than the other or is there another method I'm not aware of?

Don't bother marking the 90 & 270

Mark,

Your blank tapers over the length of the area. To get 202.5mm using 5 centers you multiplied your circumference at the large end of your wrap area (40.5mm) by 5. This would be fine if there was no taper. You're on the right track by thinking of averaging the two however. By averaging the larger butt end (40.5) and smaller tip end (36.2) you get 38.35 which you can then multiply by 5 to get a layout length of 191.75. This is your adjusted length which takes into account the reducing diameter of your blank through the decorative wrap area.

Now, think about where the center of your wrap will be. This next concept applies as you set your center to center distances from the middle of your dec wrap outwards in both directions towards the butt and the tip.

1a) For the area from the center working to the tip: as the circumference decreases, you must increase the distance between centers to compensate for the reducing circumference. And conversely, just the opposite is true:

1b) For the area from the center working to the butt: as the circumference increases, you must decrease the distance between centers to compensate for the increasing circumference.

So, very simply, larger butt diameter = smaller center to center distance, and smaller tip diameter = larger center to center distance.

2) Use the circumferences at the opposite ends of your decorative wrap to give you your first and last center distances. For the rest of your distances between centers, set the distances to proportionally increase from butt end to tip end.

Try playing around with these locations:
36.2, 73.5, 111.8, 151.2, 191.7
18.1, 54.8, 92.6, 131.5, 171.5, 191.7

Here are the spacing increments I used to get the above locations:
36.2, 37.3, 38.3, 39.4, 40.5
(18.1), 36.7, 37.8, 38.9, 40, (20.2)
Note: spacings in parenthesis are 1/2 distances to create offsets between 0/180 axis and the 90/270 axis

Hope this helps



Edited 1 time(s). Last edit at 03/19/2015 05:23AM by John E Powell.

Layout the 0 and 180 axes. After the first crosses are laid down, lay the 90 and 270 threads in between the first pass and tweak as you wrap by packing accordingly.

Hey Mark, any follow up on this? Did you try the spacing I suggested and if so did it work for you?