Introduction: Center Finder

Picture of Center Finder

I love tools and every now and then I also love tools to make live easier. This one is based on a one time tool from woodpeckers but not available anymore. So I decided to made one by myself using my 3D FDM printer.

Its a handy tool to mark the centre of a workpiece, just place the two legs around your piece and mark a line or point or draw a line with a pen trough one of the holes in the middle bar. Due to the parallelogram, the center is always found automatically.

Step 1:

Picture of

The first one was actually made with metal inserts to have M3 screws inserted to add precision and sturdiness.

The middle bar is also made out of an aluminium bar. After assembling it, I thought about this tool to share on thingiverse and noticed that you could not do this without a lathe to meek the metal inserts. So I decided to made a second version using only printed parts and some standard hardware.

Step 2:

Picture of

The pure FDM version is made using 2 M3x8mm and 4 M3x20mm counter sunk screws, the holes are already chamfered and the bottom holes made with a diameter of 2.6mm to take the screws directly without tapping.

So if you have access to a 3D printer download it here and made one for yourself.


Yonatan24 (author)2017-01-25

This looks nice. I want build an even simpler method!:

mevans12 made it! (author)2015-09-05

I just got a LULZBOT mini and this was one of the first things I have printed. I should have used a higher fill, we will see how it holds up. Great desinge none the less. If I use it a lot perhaps I'll make the one with inserts when this one is trash.


CaptAmazing (author)2015-08-26

Great idea! Thanks! ?

CaptAmazing (author)CaptAmazing2015-08-26

sorry about the question mark! ?

DanHeaton90 made it! (author)2015-02-23

Great idea! I use mine at work almost everyday for building prototype fixtures. It's quick, simple and a time saver.

mobilow (author)DanHeaton902015-02-24

wow thats bulletproof !

SuperPollo (author)2015-02-24

I never understood how the center finder works, could someone explain? :D

leanne_martinau (author)2015-02-19

Now if you could easily find the centre of a circle....

There are rulers made for just that, just do a search for center finder. Should look like this one:

Thanks spaceraver

IWorkInPixels (author)2015-02-16

Here's another version which includes some more features:

Bill WW (author)2015-02-15

Nice Instructable, thank you.

Here is the one I made, it is a useful tool.

MarcelB1 (author)Bill WW2015-02-16

nice, and so simple in its making, great !

emilyvanleemput (author)2015-02-14

Now that's something I could use!

Mark AJA (author)2015-02-13

Draw two straight lines with a ruler or straight peace of wood.

One from top left corner to bottom right corner. One from Bottom left to top right corners.

Where the two lines cross is the center.

Taranach (author)Mark AJA2015-02-13

That's great if you are trying to find the exact center of the board in both directions, but what if it needs to be offset to the side? What if you need to mark the center for a few points along the long axis... Well, you are going to need some more tools or creative math... Another thing to note is that drawing lines from cross corners only works if the ends are exactly perpendicular to the sides...

That is where a tool like this can come in handy for certain applications... just as you don't use a screwdriver for a hammer... There are tools that make a job easier and this instructable was pretty decent. It doesn't have to be 3D printed as long as you follow the same ideas with whatever materials you use for the sides and marking rails.

matthewtmead (author)2015-02-13

Wow, super cool. I will print one for sure! Nice build!

snoopindaweb (author)2015-02-13

Printed. ~(:-{)

JeffS2 (author)2015-02-13

Measuring tape and basic math always works no matter how big the piece of wood.

eye wander the goat (author)2015-02-12

Am I missing something here? Is this doo-dad simply limited by design to application? What do you do if you have a wider piece of wood? I see the woodpecker version has all these extra arms to use for adaptability.
What is the common use of this? A mass production situation where you have key parts to conform to?

I expect it's sized for his most common uses; it's easily extendable to cover a wider range of sizes.

Also the adapters for the woodpecker one are for marking a specific distance from the edge, not the center, as for marking out tenons and mortises. The size of the wood you can mark is determined by the parallelogram arms, not the center marker bar, and the woodpecker version looks to be about the same size in that regard.

Besides, if you can print these out (or just make 'em out of wood), you can easily make a set that allow for larger/shorter pieces of wood that need marking.

Actually, if you watch the video again you will see that it marks a certain distance on either side of the center (half the width of the bar) or on the center using the hole in the center of the bar.

MarcelB1 (author)bruce.desertrat2015-02-12

yes, this is done in the size I need the most, if you need to mark the center of a barn door, use the same principle...but I would measure this with a tape measure ...I see this as an idea to make one of your most common size.

tomatoskins (author)2015-02-09

This is a great idea! It gets rid of the need to break out the try-square!

GordieGii (author)tomatoskins2015-02-12

How would a try-square help you find the center of a board?

mpaula.whelan (author)2015-02-12

I think I have a drawing tool that is a parallelogram but it would only work for narrow pieces, not for length. Although I can't get a good sense of scale, I believe your gadget has the same limitation.

CraigRJess (author)2015-02-12

How much for you to make me one?

We don't have a TechShop or anything like that up here in Canada.

mrandle (author)CraigRJess2015-02-12

I can't remember if you're in calgary or not but if you are you can 3d print at the library down town or there is a place called protospace you might want to checkout thats similar to techshop.

bd5 (author)mrandle2015-02-12

3D PRINT AT THE LIBRARY DOWNTOWN????!!!!! That is sooooooo coooool! Wow! I can't believe it! Canada (Library Dept.), YOU ROCK!

CraigRJess (author)mrandle2015-02-12

Thx - I'm gonna have to check that out! AWESOME!

mrandle (author)mrandle2015-02-12

Or if that's not possible try You can send stuff to them and they print it and mail it out to you. Never tried it but ive heard of others using it.

MarcelB1 (author)CraigRJess2015-02-12

honestly, shipping costs from the Netherlands would be more than the parts may cost , make one out of wood sticks, place the bars on top of each other when drilling the holes to make sure they have the same distance.

CraigRJess (author)MarcelB12015-02-12

LOL - I guess in all my excitement to get one, I forgot to check where you reside.

bd5 (author)2015-02-12

Great tool! I couldn't figure out how it worked till I found a video on it. I found this one on yoootooob:

Same tool. What a great idea! Simple and precise!

CraigRJess (author)bd52015-02-12

Bridge City Tools has a similar "high-end" center scribe:

" frameborder="0" allowfullscreen>

nolan.kriegel (author)2015-02-12

Just looking, I thought why not a few ice cream sticks and some thumb tacks?

Quick use and throw away, or not.

kylegilbert (author)2015-02-09

Nice tool and very useful. Wishing there was a way to make this without having to own a 3D printer.

jhildebrandt (author)kylegilbert2015-02-12

Lego, my friend! There are common Lego Technic pieces that are pretty much exactly the size, shape, and function as this. Fantastic tool idea!

yrralguthrie (author)kylegilbert2015-02-12

The holes in the side pieces don't need to be centered, just parallel to the inside of each one. Need two pieces approx. 1/2" x 1/2" x 6", a couple of popsicle sticks and a stripe of aluminum approx. 1/2" wide. Can get the 1/2 by 1/2 at a hobby store, so don't need a saw. But if you don't have a table saw, then you probably don't need this devise.

Don't try to drill the holes in the center of the 6 inch pieces, just mark a parallel line with the popsicle sticks. Then put tick marks on the line using the popsicle stick ends. Drill the holes. Mark a line on the popsicle sticks using a narrower stick. Drill the holes. To ensure parallel, I would clamp the 6" sticks to themselves and drill both at same time. Ditto popsicle sticks. To drill the holes in the end of the piece of aluminum, use what you've already made. Close it on the aluminum strip. However; you will need to mark the exact center of the aluminum for the pencil. Best way for that is with a caliper set close to half the width measure and mark from each side. Center is between these lines.

The only measuring to do is to find the center of the aluminum. Can get that within .001 with the caliper or just a compass with points. Drag one point on the side and mark with the other. Can get parallel that way also. Ditto the points of the caliper.


Just make it with a few pieces of wood, or aluminum bar stock instead of plastic. The design is quite old, I imagine.

JM1999 (author)kylegilbert2015-02-09

A rubber band with a twist in it will find the middle too!

I can't deny that this is an amazing 'ible though!

Apolo8 (author)JM19992015-02-11

more info on this please

JM1999 (author)Apolo82015-02-11

The 'ible is up...

Here is the link.

JM1999 (author)Apolo82015-02-11

On the rubber band thing?

I'll be doing an 'ible on it soon :)

Edgar (author)2015-02-12


Went to my Blog.

DanT2 (author)2015-02-12

You could make it out of wood too. or any number of materials. Heck even laminated popsicle sticks, nuts and bolts.

But Agreeed it is a nice instructible.

BeachsideHank (author)2015-02-09

You're right about the drill guide inserts, one version is sold to facilitate drilling drawer pull holes on the horizontal center of the fronts (either single or pairs), works quite well too.

MarcelB1 (author)BeachsideHank2015-02-09

drill guide for drawer handles, can be done the same way just with wood I assume ...

BeachsideHank (author)MarcelB12015-02-09

True, shopmade ones are usually made of wood, plastic or hardboard and simply use a pencil inserted into the centering holes to mark the drilling location. I had one for years.

About This Instructable




Bio: collector of skills and known as Dr. Bucky Lab
More by mobilow:desk partition panelcenter finder
Add instructable to: