Center Finder




Posted in WorkshopTools

Introduction: Center Finder

About: collector of skills and known as Dr. Bucky Lab

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:

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:

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.

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sorry about the question mark! ?

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

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

Here's another version which includes some more features:

Nice Instructable, thank you.

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

Parallel ruler divider 011 (Medium).jpg
1 reply

nice, and so simple in its making, great !

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.

1 reply

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.

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

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

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?

3 replies

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.

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.