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Project by rjb37 posted 05-24-2014 02:21 PM 2591 views 19 times favorited 5 comments Add to Favorites Watch

This is an ancient tool. It will allow you to divide something into whole number parts and it will do other things too. I made this one out of poplar and a Brusso jewelry box hinge.
Picture #2 I am setting up to divide this edge into 9 equal parts by setting the legs of the sector to 9 on each end.
Picture #3 I set the dividers to what you what – here I’m setting them to 1 to get 9 equal parts. You could also use 3 and get three equal parts. It has to be a whole number – no fractions.
Picture #4 you step off nine equal parts. No measuring, no calculators, no rulers or tapes, just dividers and a sector.
You could do the same thing with just dividers but the sector makes it quicker and easier.

-- accidental woodworker

5 comments so far

View farmerdude's profile


674 posts in 2818 days

#1 posted 05-25-2014 12:09 AM

Wow, never seen one of these before. This is a great idea. I’ll have to try this, thanks for posting it. Great job!

-- Jeff in central Me.

View woodchuckerNJ's profile


1390 posts in 2413 days

#2 posted 05-25-2014 12:16 AM

Thanks, that’s a neat little tool. I have never seen this.
Seems pretty basic and easy to do, I think.
Is there any importance to the size of the sections? Probably not as long as they are equal right?

More info if you can. Any time you can eliminate calculations you increase your accuracy and speed.

-- Jeff NJ

View rjb37's profile


158 posts in 3419 days

#3 posted 05-25-2014 12:33 AM

Poplar Woodworking did an article on it and Jim Toplin has it in his book Traditional Woodworking. Sectors were also used for navigation, plotting the stars, astrology, and for doing math problems just to name a few of their uses.
Picture #1 is the second sector I made. I have two of them and I’m planning on making a 3 foot one. These two are about 24” long.
You make this with a pair of dividers and divide the arms into 13 sections. You start at the back of the barrel hinge and step off 13 steps. I could not find a reason why it is 13 steps which seems odd to me.

-- accidental woodworker

View Jack Barnhill's profile

Jack Barnhill

366 posts in 4145 days

#4 posted 05-25-2014 02:18 AM

In this post on Chris Schwartz’s blog, Jim Tolpin explains his reason for 13 divisions.

-- Best regards, Jack -- I may not be good, but I'm slow --

View Woodknack's profile


13401 posts in 3159 days

#5 posted 05-26-2014 03:58 AM

Fascinating tool, I might make one.

-- Rick M,

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