# how to find the center of a board?



## Belg1960 (Jan 3, 2010)

Guys, I saw a video somewhere on how to use a set of calipers to measure the exact center of a board that you want to resaw/rip. Does this ring a bell with anyone and could you share a link or the method?


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## Mickit (Feb 6, 2010)

I'll try…
an old method is to lock your caliper at a distance slightly larger than half of the width of the object. Scribe an arc. 
drop to the opposite side and scribe another arc. the intersection of the two arcs will be the center. Obviously this will be more accurate if the arcs are struck from a line perpendicular to one edge. to elongate the line, repeat the procedure from another point on the object. The line indicated from the two intersections will describe the center line of the object.


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## rodman40 (Jan 11, 2012)

See if this helps you out.


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## rodman40 (Jan 11, 2012)

Here's one using measurements.


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## bandit571 (Jan 20, 2011)

When I need the center of a board, like a drawer front bing fitted for a knob, I just use a straight edge.. Long enough to reach both ends of the board. I go from 'upper' corner to "lower" corner at a diagonal. Eye ball near the center make a short faint line. Repeat from the other direction. Where the two faint lines cross, that is the center. This can also be used on the ends of a board. Just make an "X", center of the "X" is the center of that board.


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## Dal300 (Aug 4, 2011)

You can always use a piece of paper to find the center. LOL.


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## Belg1960 (Jan 3, 2010)

Guys, really appreciate the help, but I want to do this on the 3/4" end of the board with such a small surface these layout tricks have let me down. Even the smallest movement when making the marks leads to one rip being thicker or thinner then the other. The method I'm talking about uses the wood to set up the tablesaw and takes into account the thickness of the blade as well. So the search still continues. I "believe" the guy that showed the method was of Asian decent but its been soooo long that I could have this confused with the hundred or so videos I've watched to try and get better.


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## waho6o9 (May 6, 2011)

Then, 3/4 equals 6/8. Minus 1/8, blade thickness, then you have 5/8.
2 and a half eights one side, 2 and a half eights the other side. The blade will be in the middle.

Or 5/16, 1/8 for the blade,5/16 will be left over.


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## Dal300 (Aug 4, 2011)

http://sawdustmaking.com/Center%20Gauge/centergauge.html


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## Infernal2 (May 20, 2012)

The trick I use is to take a ruler (you can do it with a tape measure but its a pain) and put the one corner on one side, then with the other side, move the ruler up and down so that an even number mark rests on the other side of the board. So for example, if you have a board around 7 inches and you move the ruler down slightly so that the corner rests in the left corner and the eight rests somewhat lower, then the exact difference mark will be the center of the board, in this case, the four will rest in the center.


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## CharlieM1958 (Nov 7, 2006)

Are you really just trying to rip a board into two pieces of equal width?

I just set the fence to a smidge less than half the board's width, make the rip, the send the offall piece back through the saw without moving the fence. Presto…. both pieces are identical. The only downside is 1/16th or so more waste than if you made the cut dead center on the first pass.


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## TopamaxSurvivor (May 2, 2008)

I do it like Charlie does. Get as close as I can and send the biggest through again.


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## bluekingfisher (Mar 30, 2010)

Pat, I don't know the caliper method but a marking gauge is how I would do it. Set your gauge to just a hair less than half the board thickness. Then, scriibe the edge about a 1/2" long from one face side then the other. This will give you two paralell lines on the board edge. The centre is between the two lines. You could even sneak up so the scribe lines when scribed from both sides to line up exactly.
However, if you have a gap the width of your saw blade bewteen the lines then that will be good enough, just center the blade between the two lines.


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## Belg1960 (Jan 3, 2010)

Guys, a few excellent points. 
David, I like the idea of using the marking gauge it will really help center the blade.
Charlie, Topomax being as ANAL is I am,(LOL) I try to do everything in as few moves as possible. This is the method I have been using right now and feel there has to be a more "scientific" way to move ahead.
Dallas, buddy I will make a few of these types of marking gauges. They will come in handy. I didn't get the paper tip or was that just you being funny. Just went over my head I guess. LOL
Infernaln2 the method you describe is really closely related to 1 of the links in the earlier post.

Many thanks men very much appreciate the support. If someone does find the method with the calipers plz post it here.


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## 280305 (Sep 28, 2008)

I usually use Charlie's method for ripping into two equal widths.

But sometimes I use a ruler/pencil or marking gauge that is set to be close to half the width (by a quick measurement or eyeballing). I make a mark from both edges of the board. Whether I am set a tad over or under the exact target width, I end up with two marks close together and centered on the board center.

I set the fence to put the center of the blade in the center of those two marks and make some test cuts. If my actual board is over-length, I will do this right on the end. I just flip it over to put the other edge against the fence to check.

I often use this two-mark method to locate the center of the width of a board for reasons other than ripping - say locating a drawer handle. I also do this on the edge of a board to find the center of the thickness so I can set the fence on my bandsaw when resawing.


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## dhazelton (Feb 11, 2012)

Yes, math never lies. You want to rip a 1×4 in half say, it is 3 and 1/2 wide. Subtract 1/8 for a kerf and you have 3 and 3/8. Divide by two and you have 1 and a half plus 3/16, or 1 and 11/16.

If you wanted you could make yourself a set of spacers that when set against the blade will set your fence to width depending on what width board you are cutting. Make a 1 11/16 spacer and write "1X4" on it. Add a half inch and cut another one that says "1X5" on it. Make a whole set an drill a hole in them and hang 'em on a hook somewhere.


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## Dal300 (Aug 4, 2011)

Pat, the piece of paper method wasn't a joke and it works. I've used it when I didn't have anything to make a gauge out of.

It goes like this:

Grab a piece of scrap paper and a pencil.

Lay it on a flat smooth surface.

Put the board you want to find the center of on the paper and mark the edges.

Remove the board.

Fold paper in half, so that the two marks meet.

Where the fold is….. is the center of the board.

Hold one mark on the paper at the edge of the board you used so the fold is at the center of the board and mark the board.


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## CharlieM1958 (Nov 7, 2006)

Jonathan is correct on the math. And yes, math never lies. But any method of making marks and setting the fence to the center of those marks, leaves room for mechanical error. If you are really anal about having both boards the same width, I don't think there can be a more accurate method than cutting slightly off-center and running the larger board through without moving the fence.

So, pick your poison… Do you want to be anal about making the fewest moves, or anal about being accurate?


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## DS (Oct 10, 2011)

Option C: Recognize that being anal may not be the best way to enjoy life and just get it close enough for all practical purposes. Then, get on with your life. ;-D

I say that knowing, that when it comes to woodworking, I am probably the most anal person on the planet. hehehe.

Do I have too much stress? Do I worry too much about having too much stress? The whole thing stresses me out.

Git' er done!


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## 280305 (Sep 28, 2008)

Math may not lie, but …


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## dhazelton (Feb 11, 2012)

@Chuck - that was good, and the hat hook at the end was brilliant.


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## TopamaxSurvivor (May 2, 2008)

Too much time spent in layout, ect.; therefore, fewest moves may not be the fastest way ;-))


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## MT_Stringer (Jul 21, 2009)

So I took a 3/4 inch thick board and made a mark with my try square at 90 deg across it. Then I used the line to indicate where the 45 deg angle of the try square should be and made a mark near the center of the piece. Then repeated from the opposite side and voila! perfect centered X in the middle of the 3/4 inch piece of plywood. No measuring or anything. Setting your saw up requires operator input, not math. 

Good luck.


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