Center Finder Jig or Marker




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Hello again! Here is an instructable about how to make a line center finder jig/marker.

This is easy to make and easy to use. A very nice thing to have in the workshop or if you are doing some construction work.

How it works

The jig/marker is used to quickly find the center of a board or workpiece and trace a line. This is especially useful if you are resawing, splitting or wanting to put nails or screws in the center of a board.

When you twist the marker, the dowel pegs will register on the edges and make the pencil follow the exact center of the work piece.

Before we start

If you like to see all the steps in moving pictures, there is a small and short video about how I made the center finder jig here.

This project took under an hour to make. Doesnt require many tools and suits beginners.

This idea is not mine and there are many center finders out there. This is just how I made mine. You can adapt and change yours as you se fit. Here are some cool instructables that I have found about making center finders :

By mobilow (3D printed)
By Phil B
By superthunder bolt

Grab a coffee and let's get started...

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Step 1: What You Need

I made a layout of all things I used this time. In my video I might use an adaption of the tool, but you can go about however you like.


  • Wooden strip (about 12 cm long and about 0,5 cm thick).
  • Wooden dowel (I used 10 mm)
  • A pencil


  • A ruler
  • A square
  • Drill with 10 mm drill bit and a 7,5 mm drill bit
  • Wood glue
  • Sand paper
  • Pen
  • A saw (to square of the wooden piece if needed)
  • Optional awl (or smaller drill)

Oh! And if you dont have any dowels? No worries! You could use a nail, screw or make your own dowels! Either check out my other instructable or this little video of the dowel maker. :-)

Step 2: Finding the Center

I start by finding the center of the wooden strip. This will be where the pencil be mounted later. Be very careful when you make the marks, because you need to get the center right and the distance to the dowels exact, otherwise the jig will fail.

I trace a line from corner to corner. This way I dont need to measure anything and where the two lines cross, there is the center of the work piece.

Step 3: The Layout

I then use a square and make a line down the center (If I had a center finder jig I would have used it here!) :-)

The line is only so that I know where to put the center of the dowels later.

I measure 5 cm from the center on each side.

Step 4: The Markings

Here you can see the dots and layout.

Be very careful when you make the holes in the next step.

Either use a smaller drill bit to make a pilot hole, or an awl in each of the 3 dots.

Step 5: The Holes

Drill the holes. Be careful and exact!

I had a hard time finding a 7,5 mm drillbit. 7,5 mm seems to fit most pencils perfect with a snug fit.

The two holes on the sides is drilled with 10 mm size drill bit.

Step 6: The Dowels

You can buy readymade dowels or you can make your own. :-) Either check out my video here on how I made that dowel maker or this instructable here.

I cut the dowel to about 4 cm long and glue them in place.

Step 7: The Result and Final Words

I hand sanded the jig. If you feel like it, you can make a small roundover on the edges. Doesnt affect the functionality, but feels better to the touch when used.

How to use the center finder jig

Well. Place a sharp pencil in the center hole and place the jig over your work piece. Twist it until the dowels register to the edges and trace along the piece. Please note that when the end is reached you cannot make the line all the way to the end of the work piece. Just use a straight edge or a ruler if you need to complement the line.

In the end of the video you can see how I use the jig.

The end

Thank you for reading this instructable. It was fun to make. Please consider to follow me here on instructables. It will fuels me to create more and better content in the future! Please leave a comment below and let me know what you think, or if you have any question. I will try to answer asap.

Here is that video again, if you want to see everything animated and in motion.

Thanks again - have a fantastic day!

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    12 Discussions


    1 year ago

    Nice way to do it. Many years ago I used a piece of wood with two 2" nails thru it at the ends spaced 6 inches apart with a third 1.5" nail centered exactly between the outer two. worked very nicely but yours can also make a pencil mark without scratching the surface, just in case you need to find the center of something valuable. I made mine just as an aid in the carpentry box.

    3 replies

    Reply 1 year ago

    Hi - and big thanks for commenting! I totally love the nails solution too, and thats the "original" jig :-) Something I wish I knew about years ago. Perfect for construction carpentry. I love these things that makes the progress quicker. Thanks again for commenting and sharing!!! Much appreciated! :-)


    Reply 1 year ago

    I use nails or screws for many things besides what they are made for. eg take a stick (this is the handle) put a nail into it along its long axis. cut off the head. hammer the end so it is flat and thin enough to fit into the slot of your sprinkler head and then make a slot on one side of the flattened area to make it like a hook. Voila you have a way to clean out your sprinkler heads when they get blocked. once you start on this track you can find many uses for nails and screws.


    Reply 1 year ago

    Hey! Thanks - great tip! I will keep that in the back of my head for future reference! :-)


    1 year ago

    Very nice. I love it. Represents the best in precision from an analog device. The simplicity makes form and function satisfy art and technology in a beautiful way. Even if the edges of the work you are marking were not perfectly parallel it still finds the exact center line between them quickly and easily. Big fan of simplicity and bottom lines in engineering and most aspects of life.

    3 replies

    Reply 1 year ago

    Thank you very much! I love how you put words to this. Almost like poetry and engineering comes together. And I totally agree with you. I really appreciate this and wish you a fantastic day! :-)


    Reply 1 year ago

    Well thank you too. I have always been a seeker of truth and purity and sometimes when form and function come together in what becomes the purest and simplest way it derives an elegance that can't be matched in this virtual and digital world of false reality. Analog devices always appeal to me due to their basis in reality and inability to be complicated by digital trickery and pixelated slight of hand. Strange stance for a guy that has spent decades in electronics engineering and computer science but there is a little of my philosophy for you since you enjoy combining art and technology. The older I get and advanced in my career the more appreciative I am becoming with what some would call more "organic" systems and processes. Anyway, credit where its due, I seldom comment on anything anywhere but I really enjoyed the well designed instructable and, as said before, the form, fit, and function of your tool. Nice work.


    Reply 1 year ago

    I agree with you in so many ways. I too work with technology and I appreciate art, labor and simplicty more so now than ever. What I do in my work, never lasts or can be seen from outside a computer. Building, constructing or creating something that can be enjoyed for a long time after its done, gives me satisfaction. Thanks again! I appreciate your comment and support!

    Alex in NZ

    1 year ago

    Nice jig, but I totally love the pencil holder from a piece of pallet in the background. Thank you for both ideas :-)

    1 reply
    dekerosAlex in NZ

    Reply 1 year ago

    haha. Thank you for that! I like it too. It's makes me smiles sometimes and it looks kinda cool with the pallet markings left. :-) Thank you again - much appreciated!


    Reply 1 year ago

    And thank you for watching, reading and commenting! Tip of the hat! :-)