Any one got any easy ways (other than by eye) of laying out the space between threads to leave a gap for say 6 threads to wrap inwards
When I do it ny eye i always have trouble "packing" because the gap is not always right
Also what is the easiest way to ensure threads cross at 90 degrees on a tapered blank When I try clemens method it starts ok then runs out to an acute angle towards the end of the taper?? even when using a layout jig hence my wraps always seem "off centre and twisted"

Any suggestions welcomed
thanks
allen

Short version of this:
For SQUARE Diamonds: DELTA = PI * OD
For NON-squares <> use: DELTA = PI * OD * TAN(THETA)

where:
DELTA = distance between centers
PI = 3.14159 ...
OD = Outside blank diameter (with or without underwrap)
TAN(THETA) = the tangent of the angle Theta
THETA = the pitch (or rise) angle of the wrap.

For a SQUARE DIAMOND, the pitch is always 45 degrees.
Therefore, the TAN(THETA) = TAN (45' ) = 1.000000,
which means that the TAN(Theta) term in the equation
is LATENT (or drops out ) and DELTA = PI * OD

As far as your calculating the numbers of threads between the X's in a CLOSED WRAP – Yes, that can get plenty tricky plenty fast. You can wrap your intended thread around a scrap section and hand COUNT the number of threads per centimeter to determine the number of threads in your pattern that will fit between the centers. That’s where Dave Boyle's VISUALWRAP, or that piece of Xmas wrap paper or that clean sheet of computer paper can help you visualize what is going on and how to measure that distance in your pattern. The off-the-cuff method just fills-in until you are done. Then burnish to spread them out or jam them in there as needed.

I will bow out here, because I am not doing critically-tight closed wraps. So the voice of countless such experiences is your best bet. I hope this helps for now. Just chant the names of some of the MANY Thread Masters around here (Doc Ski, Vivona, Upton, ET AL) and you will soon conjure up these “Wizards of Weave” and “Dukes of Diamonds” to help set your troubled soul on the right path to butt-wrap bliss. ...

Na-mas-day, ... (or something like that) -Cliff Hall+++

P.S. - No disrespect to the countless other thread experts and artists here at RBO whom I did NOT mention. I'm just trying to be brief. ... It's one of my New Years resolutions!. LOL !!!, -CMH+++

Cheers Cliff i`d forgotton all my trig stuff LOL
That works on a straight rod but I still cant grasp it on a tapered rod which is 28mm OD to 25mm OD on a 150mm length
the formula i used was
TP=taper L=large od l=small od D=length
TP=L-l
D

angle = tan = D
2
but it comes out at less than 1 degree which is definatly not right ????
maybe time for either visual wrap or give up lol

Hi Allen,

Just to let you know that the VisualWRAP software implements the Tapered Offset Layout (TOL) formula as described in the Clemens' book (Custom Rod Thread Art).

If the rod has no taper then square spacing (90 degree crossings) is achieved using a spacing of one circumference.
On a tapered rod the circumference changes as you move along the rod. The TOL formula suggests the spacing at the skinny end should be the circumference measured at the fat end, and vice versa. This allows the threads to fit nicely, however has the side effect of compressing the pattern at the butt end, and elongating it at the tip end.

The vizwrap software shows this graphically by drawing the pattern with TOL spacing applied, so you can see just how much (or how little) the pattern will be distorted. It also calculates the spacings and presents them as a list of measurements in a table.


Cliff- you're a crack up!! :-)


Thanks
Dave Boyle
www.visualwrap.com

Dave Boyle - If you see this, ... - It seems that a rigorous attempt to solve this geometric conundrum for correcting the spacings on a tapered rod by equations using spacing distances and pitch angles and rod blank OD's and trigonometry is a never ending cycle of having at least one too few equations to solve for all the variables in a given set of boundaries.

Dave … Is that essentially true, in your experience, as the man who wrote the computer program for your VisualWRAP? ... Or have I simply cracked up while trying to solve this Rubik’s cube too precisely…?…

I have been thru about a dozen diagrams & iterations for deriving formulas for these parameters, and it just seems to lead to the introduction of the next inexpressible variable. … (Kind of like Heisenberg's Uncertainly Principle. ... Defining it changes it.)

Anyway, my final useful conclusion seems to be that increasing the (Spacing of Centers) at the same rate of the (Rod Taper) is a valid and very close approximation to what the elusive solution actually is. ... Is that correct...?... By this (my) method, the thread filling distance would (should) remain constant, from end to end. But the distortion of the diamond may be noticeable, maybe more than the TOL method.

The error in this (my) approximation seems to be within the same percentage as the percent Rod Taper itself. (That is, for a Rod Taper that is 2.00%, the error from ideality happens also to be ~2% (1.96%).)

I just re-read Dale Clemen’s section on Taper Offset Layout in CRTA, pages 21-23, prompted by your reference. In effect, his conditions for the TOL Formula seem to select the middle of the butt wrap as the “EXACT” position. No error there, in squareness nor thread filling. The TOL correction introduces a slight and simultaneous change in diamond shape (pitch angle) and thread filling as you move up or down the rod blank, as you described above.

In response to Allen Forsdyke’s question & Post, I sought a way to EXACTLY keep the thread filling distance (for a closed wrap) exactly the same, as you move from fore-grip toward the rod tip. My elaborate sequence of solutions culminated in a solution from the Pythagorean Theorem.

[H = SQRT(A*A + B*B), where: H is directly related to the thread filling space; and A involves the rod blank’s OD, and A contains the rod taper term; and B involves the distance between the centers, and B contains the variable sought (the percent change in center spacing).]

In the end, this gave a formula that says that the increase in center spacing would be a fixed percentage (the percent Rod Taper) of the previous spacing interval. The thread filling should remain the same, but the diamond's distortion may be too noticeable or unbalanced. As Clemen’s said, the actual fractions of a millimeter involved in these fine adjustments may be unreasonably impractical, especially on small diameter rod blanks. (Clemens example was a 1-cm OD rod blank. For a large 1-inch OD section like Allen’s, whose spacing is ~80 mm, the correction would be ~ 2 mm per center, which is doable.)

In the final analysis, it seems that simply inverting the center spacing distances, as done in the TOL Method, remains the best blend of accuracy, aesthetic appeal and practicality.

IMO, … I tried, …!!! …
-Cliff Hall+++, cmkmhall@ufl.edu
Gainesville, FL-USA*****

Hi Cliff,

From the outset I will state I don't know what the answer is. Tempting as it is to find the ''exact'' answer, there are extra variables at play, including irregularities in taper and differences in thread tension that may not be captured in a formula. In my (limited) experience the TOL method and a bit of burnishing gives a result that works. My head starts hurting when things get complicated :-)

One thing that was not obvious to me about TOL until I coded the software and saw the result is that if you look at a single thread spiralling up the rod, that thread needs to spiral at a variable angle along its entire length. Hard to explain, but you can see it in one of the screenshots: [visualwrap.com] Look at diagram 3. The threads in the Taper View look like they are curved when shown laid out flat. That is because they need to be in order to achive the variable spacing along the rod. I guess this is the pitch angle effect you are referring to.

Vizwrap creates the Taper View by taking a flat 2D image of the wrap (laid out flat) slicing it into vertical strips, distorting the vertical and horizontal dimensions of each strip then reassembling the image. Vertical distortion (compression) gives the image its taper. Horizontal distortion (elongating or compressing) implements the TOL. In the centre of the image there is no horizontal distortion. As you go towards the butt end or tip of the wrap the horizontal width of each strip is compressed or elongated a proportional amount. The boundary condition is that the length of the overall image (ie the wrap) must remain constant. Results achieved graphically (ie printing out the Taper View true-to-size and measuring centre spacings) match those achived by calculating the spacings directly. IMO the graphical method is superior because it allows you work with patterns which are not square to begin with, whereas using the spacing table to calculate centre distances begins with an assumption that the pattern is square.


Thanks for your post as it got me thinking again.

Tight Wraps
Dave Boyle
www.visualwrap.com

Before I forget: - TO ALLEN FORSDYKE - YES the TAPER ANGLE (PHI) on your fising rod quoted above, over those 15cm of the rod blank, is indeed less than 1.000 degree. It is, in fact. 0.573 degrees. -Cliff Hall+++

The formula is TAPER ANGLE (PHI):
TAPER ANGLE (PHI) =
ARC-TANGENT [ (1/2) * PERCENT TAPER / 100 ]
PHI = ARC-TANGENT [ (1 / 2) * [OD(1) - OD(2)] / (LENGTH) ]
PHI = ARC-TANGENT [ (1 / 2) * [ 28 - 25 mm ] / (150 mm) ]
PHI = ARC-TANGENT [ 0.500 * [ 3 mm ] / (150 mm) ]
PHI = ARC-TANGENT [ 0.500 * [ 0.0200 ] ]
PHI = ARC-TANGENT [ 0.0100 ] = 0.573 DEGREES

Let PERCENT TAPER = 100 * [ [ OD(1) - OD(2) ] / (LENGTH) ]
[I recognize that some people may use another definition for the percent taper, but in the context of this discussion, this definition works best, IMO.]
TAPER ANGLE (PHI) =
ARC-TANGENT [ (1/2) * PERCENT TAPER / 100 ]

For fishing rods, typical values are:
PERCENT TAPER: 0.50 - 2.00%,
TAPER ANGLE: 0.150 - 0.600 degrees

What is really amazing, IMO, is how profound an effect such a tiny magnitude of taper can produce. A mere 1% taper or 0.5 degree taper turns a simple hollow narrow-diameter tube into one of the most versatile and elegant load bearing elements in structural engineering. Really ingenious when you think about it. -CMH.

"If you cannot measure it, if you cannot express it in numbers,
your knowledge is of a meager and unsatisfactory kind." -Lord Kelvin

"In my (limited) experience the TOL method and a bit of burnishing gives a result that works. My head starts hurting when things get complicated :-) " - Dave Boyle.

I still have a headache from working some more on this today before lunch. I wrote up some more notes, mainly for myself, which I may Post later this week.

I am friends with a fisherman who is a Visual/FoxPro & ColdFusion programmer, and who has an serious fascination with higher math & topology. He showed me the most fascinating geometry book I have ever seen called "Visual Complex Analysis" by Dr. Tristan Needham, PhD. I didn't understand many of the equations, but the graphs and 3-D diagrams were very intriguing. Projections of 2-D plots onto 3-D surfaces and vice versa were all over this textbook. This seems particularly relevant to decorative butt wraps on a fishing rod. Even you may find VCA-NT interesting as you move VisualWEAVE to market. [www.amazon.com]

I'm gonna run some ideas by this friend to see if my stuff makes sense. If it does, I may open a new Thread on this subject. I have gone thru a maze of sets of equations over the weekend, I don't want to go on another wild goose chase for an elusive solution that can't be found. ... We'll see, ...

And like you've said, Dave, the PRACTICAL APPLICATION is the real goal. The higher math my be more sensitive to the non-ideality introduced by the rod's taper than the actual process of butt wrapping. ... But it just seems that there has to be a way to generate a set of valid equations that has derived solutions, and not just imposed approximations. So that's my fixation for now.

Thanks, Dave for your response and sharing the background on VisualWRAP. In light of the fact that Clemens' book Custom Rod Thread Art is now out-of-print, it seems that VisualWRAP is destined to replace CRTA as the standard reference for the next generation of rod builders.

Thanks again & Good Luck, ... -Cliff Hall+++FL-USA