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Jig to find center of board width

WERD's picture

To ALL: Can not remmber how to make a jig to find center of the width of a pc. of lumber.No tape to use seems tha it was a  long thin pc of wood with pegs a each end. Need help on this.Andy 

KiddervilleAcres's picture

(post #87013, reply #1 of 8)

Measure the width of the board.  Set a framing square with that width on each leg and the tip of the L is center.


Regards,


Bob @ Kidderville Acres


A Woodworkers mind should be the sharpest tool in the shop!

Bob @ Kidderville Acres

A Woodworkers mind should be the sharpest tool in the shop!

Jigs-n-fixtures's picture

(post #87013, reply #2 of 8)

The jig is a piece of wood with three equally spaced holes in it.  The two end holes have pins in them, and if you rotate it until the pins hit the edges, the one in the middle is at the center of the board. 


You can also do it with a ruler.  Set the ruler on the board so that the edges line up with inch marks, say the 2 and 7.  The difference is 5, so the middle is half of that or 2.5 inches away.  So, add the 2.5 to the 2, and mark at 4.5. 


The ruler method will also find thirds, fourths, fifths, etc.  Say you want to mark a 5.5 inch wide board in thirds.  I'm good at math, but your headed into fractions (1/6th of inches), that aren't on rulers or tapes, so why bother.  Just, put the ruler on the board so you span six inches side to side, and mark at the 2-inch points, and you have it divided in thirds. 

JamesS's picture

(post #87013, reply #3 of 8)

Werd: I use a "centering" rule.


James

Routerman's picture

(post #87013, reply #4 of 8)

Centering straight edge.

KiddervilleAcres's picture

(post #87013, reply #5 of 8)

Here's another from Norms dad :>)


http://www.bobvila.com/HowTo_Library/Finding_Center--T179.html


Regards,


Bob @ Kidderville Acres


A Woodworkers mind should be the sharpest tool in the shop!

Bob @ Kidderville Acres

A Woodworkers mind should be the sharpest tool in the shop!

Willy's picture

(post #87013, reply #6 of 8)

Just lay your ruler across the wood on an angle i.e. one inch marker is on one edge and, say, 7" marker is on the other. The centre is
(7-1)/2=3"marker!!!

blewcrowe's picture

(post #87013, reply #7 of 8)

Don't really need a jig. Use a ruler. Say a 12" one, for example. Skew it so that the beginning is on one edge of the board, and make the other end of it end at the opposing edge. The 6" mark will be dead center.


I don't know if I'm explaining this well.


The other way is to make a jig of virtually any length, with a dead center pin in it and fixed pegs on the ends. Skew jig over board and make both pegs touch its corresponding edge. Your center pin will be center.


And some companies make tape measures with centering readings. Later.

 

Denny

danmart's picture

(post #87013, reply #8 of 8)

Werd


This tool you are vaguely remembering is a tool used in finding the center of tapered spars in the boatbuilding world. Like others have said- take a piece of wood a little longer than the widest section of the long board and put a peg(cylinder) on each end. I use 3" bolts and cut off the head. I epoxied the threaded end of the bolts in the piece of wood at each end. In the dead center between the bolts, I drilled a small hole and screwed a drywall screw in so the tip just comes above the surface on the side that the bolts protrude on.


I can scribe a center line on a tapered spar 16' long by holding the tool at an angle against the sides and have a perfectly centered scribe line.


Trouble is: Its so ugly and easy to make I can't find it now or I would take a photo and post it. I use a double pin tool to make octagonal oars and pencil post bed posts that I will plane to the lines. Its worth the trouble of making.