Is there a general rule for center spacing in closed wraps????? i am working on a spider and the rod diameter at the top of the wrap is 19mm, the base is 24mm (surf rod). What is the general distance progression i should use for the centers.....any help is appreciated.........thx

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thx for the link.....just put in my subscription order for the magazine.........cant wait to be able to answer my own questions.....lol...thx again

try this its so simple its painful
Using a ruled piece of paper with a vertical margin line at the left side and the slip of paper marked with the circumferences, the TOS can be laid out graphically on the ruled paper. Transfer the circumference of the butt to the top line of the paper beginning at the left vertical margin. Since there will be five cross over points in the wrap, count down the first five lines on the paper and transfer the tip end circumference to the fifth line. Using a ruler connect the two circumference markings with a straight line. You now have the distances figured out for the tapered offset layout. They are the distance between the left hand margin line and the right hand line.
However, when you layout these distances on the axis, start with the TIP end measurement and place that distance beginning from the BUTT end marking. The next distance going toward the tip will be the next line above the tip distance on your chart. Continue working up each line and transferring that distance to the rod blank until the last line (the butt circumference) is transferred to the tip end of the axis. The distances on your chart are reversed during the layout on the rod blank, so the smallest distance is closest to the butt end and the longest distance is closest to the tip of the rod. These variable distances between the cross over points will allow for the taper of the rod in a closed wrap.

Jason Jarc - If you are willing to tolerate some pattern distortion from square at the ends of the wrap, for the sake of an easier time of space filling when you close the wrap, then consider this:

What's the DISTANCE between the 19mm and 24mm OD?

Use an average diameter = 1/2 * (19 + 24) = 21.5 mm
For a 90-degree square diamond pattern = DELTA = PI * OD.
Delta = Center Interval-Spacing = 3.14 * 21.5 mm = 67.5 mm.
At the center of the pattern, it will look the most "perfectly" square.

Anything between 65 - 70 mm will look square enough, as you prefer. If you go with a shorter distance, like 60 mm, that will compress the pattern along the long axis. But that may still look very nice and make the math and the layout easier. 60 mm is a long distance between spiders, depending on how large you make them. ...

That's the short & simple on that, IMO, ... Cliff Hall+++

8:00PM - P.S. -
Assuming a 3.3% Taper (24-19 = 5mm / 6.0" = 150mm)
TOL: Something like
[BUTT]: 60, 62, 64, 66mm :[TIP] over 10.0". Or
[BUTT]: 50, 52, 54, 56mm :[TIP] over 8.5".

9:00PM - P.S. -
If the Taper is closer to 2.0%, (24-19 = 5mm / 250mm)
TOL: then something like:
[BUTT]: 50, 51, 52, 53, 54mm :[TIP] over 10.25".



Edited 3 time(s). Last edit at 02/21/2006 09:09PM by Cliff Hall.

I think he is asking about lengthing the space between centers as he moves up the rod. This allows for all threads to fit when making a closed wrap.

Some years ago when I was heavily into cross-wrapping, I just used a simple method to do all this. I still it's easier than anything else I've ever seen and I'll toss it out here. Most of the large saltwater blanks I was working with weren't sharply tapered, so I won't guarantee that it will work on all blanks, but I wouldn't be suprised if it will.

Calculate the percentage difference between the circumference (or the diameter - this works pretty well with either). Now divide that by the number of centers you plan for your wrap to have. Now take that amount and multiply it by the length of your first desired center. Do this to each result. That's really all there is to it.

For instance, with what you have there, you're looking at a 21% differentce between the starting and ending diameters. Divide by say, 8, for a result of about 2.5. Now let's say you desire to have your centers 20mm apart (working in mm is much easier when doing cross-wraps). Space the two centers 20mm apart, then multiply 20 by 1.025 for a result of 20.5mm. Space the next center at 20.5mm. Now multiply 20.5 by 1.025 and the result is 21. Space your next center at 21mm. So on and so forth.

This is by far the easiest way to do this. Play with it and see what you think. It served me well for many years.

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