7/10/7 Rule

[whaynes]

I have seen this referenced as applied to forming eight-sided poles in configuring masts and spars.  Can someone explain this for me?

                                     Walt Haynes

[Mark P]

Hi Walt;

 

This refers to the proportions to be used when creating an octagonal section from a square section.  You measure 7 units in from the corner,  along 2 adjacent faces,  then a further 10 units,  then a further 7.  This is then repeated on the remaining 2 sides.  Joining all the points at 7 units with lines to make triangles will result in an octagon.

 

Put another way,  any square timber should be divided along its faces into 24 units,  and then those units split as above. 

 

When working with inches,  24 units is relatively easy to find.

 

All the best,

 

Mark P

Edited July 17, 2016 by Mark P

[mtaylor]

HI Walt,

 

This may have more info that what you want, but here's a link:  http://www.pettigrews.org.uk/lm/page030a.htm

 

There is an excellent article in the database here:http://modelshipworldforum.com/ship-model-masts-and-yards.php

 

There's also these:  

http://modelshipworld.com/index.php/topic/12265-mast-shaping-help/

http://modelshipworld.com/index.php/topic/12533-working-the-masts/

http://modelshipworld.com/index.php/topic/2876-octagonal-spars/

http://modelshipworld.com/index.php/topic/2128-octagon-portion-of-a-yardmast/

[whaynes]

Thanks for the quick responses.  All I need.

                     walt