Introduction: DIY Center Finder Tool

Hi everyone!

In this quick ible I'm gonna show you how to make a useful Center Finder tool using just scrap materials that you can find easily in your home.

Thanks to this simple, yet accurate tool you will be able to quickly mark the center of your square or round workpiece, saving a lot of time.

Step 1: Materials & Tools

MATERIALS:

- 2x scrap pieces of wood

- 10cm x 10cm plexiglas
(the clear side of a CD cover would work as well)

- 3x long wood screws

- 2x flat-head screws

TOOLS:

- drill

- wood glue

- clamps

- precision square

Step 2: Cut and Glue

First of all find or cut two small pieces of scrap wood (mine measure 8cm x 10cm).

Apply wood glue on the joint and clamp the pieces together being sure to let them dry in square (photo#1).

Step 3: Reinforce the Joint

After 15 minutes reinforce the "L piece" adding 3 long screws.

Be sure to pre-drill the holes in order to avoid cracks.

Step 4: Cut the Plexiglass

It's time to work on the plexiglass piece.

First of all cut a piece of the right measure (mine is 8cm x 10cm), and then make a 45° cut.

Plexiglass is an easy material to work with. You could cut it using a jigsaw or a metal saw but I found easier to cut it making a lot of scores with a knife, and finally I bent the piece with my hands breaking it along the line.

Step 5: Secure the Plexiglass to the "L Piece"

In order to secure the plexiglass to the wood I drilled two holes in both pieces, and then I secured it using two flat-head screws.

NOTE: don't tighten them too much or you will break the plexiglass.

Step 6: Use It and Find the Center of Everything!

And here it is! After just 20 minutes (I hate to wait for the glue to dry) we have a simple yet accurate tool that will save you lot of time when you need to mark the center of a workpiece.

It's specially useful for round pieces. Lay your workpiece in the corner against the plexiglass and the wood, mark a line along the 45° plexiglass edge, rotate the piece a little and mark another line. Congratulations! You found the center. (a 3rd line is needed just the first time to check that your DIY tool is accurate)

Thank you for reading my Instructable. ;)
Feel free to comment and ask if you need to know something!

manuelmasc

Comments

author
logwolf (author)2016-12-11

Will this exact size jig, work with any size item needed to find center?

author
Waste Of Space (author)logwolf2016-12-11

No, it will only work with things that fit into the jig.

However, there is no reason why you could not scale the whole thing up and use timber with a measurement of 500 x 500. This would allow you to find the centre of items up to a metre in diameter

author

this will work on circles of any dimensions. you just need to mark a small line (even in the corners of the circle) and then extend the lines tool the end with a scale.

author

Yes! You can scale it to any measurement that fits better your needs, or you could lay a ruler onto the 45° plexiglass edge in order to temporarily extend the capacity of this jig keeping it small enough to don't waste materials and space around your workshop.

I'll upload this ible with a simple trick that can be followed to use it with circles or squares of ANY dimension. Stay tuned! ;)

author
manuelmasc (author)logwolf2016-12-12

Hi Logwolf! The only limit of this jig is the 45° line.

In my case (since I used just scrap materials and since I don't usually work with big workpieces) it measures about 8,5cm. This means that I'll be able to use the edge of the plexiglass to mark the center of a 12cm diameter circle or a 12cm square. (look the 1st attached photo)

BUT since the 45° line passes through the center of any workpiece that is placed against the 90°angle (aka the wooden pieces faces), I could still use it to mark the center of a square bigger than 12cmx12cm, simply by placing it against the 90°angle, and laying a ruler onto the 45° plexiglass edge. (look the 2nd attached photo)

You could use the same method to find the center of circles bigger than 12cm just if the height of the wooden pieces (from the origin of the 90°angle) is the same. In my case since I butt-jointed two pieces of the same measurements, I ended up with one side of 6cm, and the other of 8cm of height.

Thanks to your comment I'll upload this ible with more infos about the limit of this jig, and with a simple trick that can be followed to modify this jig in order to use it with circles or squares of ANY dimension. Stay tuned! ;)

IMG_4155.JPGIMG_4154.JPG
author
mOWWck (author)2017-01-04

I wish I had seen this years ago! Had wood and lexan laying around, had it all together in 20 minutes. Nice and simple!

author
guy90 (author)2016-12-16

Pheww, now I can mark Centre lines without having to research mathematical techniques that I'd struggle to understand anyway! Thank you for the info

author
manuelmasc (author)guy902016-12-20

no problem man! nice to know that I saved another life from math :P ahahahha

author
Leonardned (author)2016-12-11

great idea and real simple. My suggestion would be to use an old plastic mechanical drawing plastic triangle, or just buy a cheap new one. Sometimes getting plexiglas to score and break accurately is problamatic. The triangle is right on.

author
manuelmasc (author)Leonardned2016-12-12

If you score it 5/6 times along the line it becomes very easy to break along the line, but absolutely yes!! that is a quicker and easier way!

Thanks for your suggestion! I'll add it in the ible!

author
Leonardned (author)manuelmasc2016-12-12

The biggest challenge will be drilling the plastic or plexiglas without it cracking.

author
Mihsin (author)Leonardned2016-12-18

Drill Plexiglass with wider (flater) drill bit tip, aroung 120 degrees

author
Leonardned (author)Mihsin2016-12-19

good idea since the bite will be less drastic and not as likely to produce as much stress.

author
PhilS43 (author)Leonardned2016-12-12

Perspex is a sod to work with and cracks just by looking at it - drilling is the worst. Drill slow and preferably in a drill press. Don't go for the finished hole size straight off, go up in drill sizes. Otherwise, use a reamer.

The centre finder doesn't need clear plastic, so just use PVC sheet which is a doddle to work with.

author
manuelmasc (author)PhilS432016-12-13

you are right but it's just "plastic"... let's not panic for breaking it ahaha

make a small pilot hole, drill slow and the holes will be done!

thanks for the comment anyway!

author

I have worked with optical acrylics on military aircraft. They do make acrylic drill bits that have a longer. More pointed tip. But using a regular drill bit, drill at a fast speed but very low feed...almost spinning in place...to heat up the plastic ahead of the drill bit tip. Also it is advised to drill a pilot hole then step drill with a unibit to the final size.

author

right! a small pilot hole is a good suggestion

author
CaitD1 (author)Leonardned2016-12-12

I would suggest perhaps a small point soldering iron to melt through it. It should go through quite easily. I have put holes in plastic that way before. Works like a charm. No cracking.

author
manuelmasc (author)CaitD12016-12-13

yes! and it reinforces the edges of the hole too. the only "problem" is to find a screwdriver of the right dimention

author
manuelmasc (author)Leonardned2016-12-13

you just need a drill bit of the right size and you have to drill the plastic at a very slow speed.

another easy method is to heat a screwdriver with a lighter in order to melt the plastic creating the hole.

author
loubee2 (author)Leonardned2016-12-11

I'm a newbie working with wood etc., but this seems like a very useful tool & the suggestion about the using a triangle makes it even easier!!!

Thank You both for a great idea(s)!!!

author
manuelmasc (author)loubee22016-12-12

Thanks for the appreciation

author
KristenL17 (author)2016-12-14

I love this! Made own speed square for same reason... but this covers circles!... im a big fan of.... "Do it once properly (for the sake of the jig) and you'll never have to do it again! :)

author
manuelmasc (author)KristenL172016-12-15

ahahah good way of thinking

author
zposner (author)2016-12-12

great because I normally jus guess

author
manuelmasc (author)zposner2016-12-13

ahahahha the guessing technique is the fastest and the easiest but definitely not the most accurate one... it depends on the project that you are working on

author
keets (author)2016-12-09

This is not the first instructable of a centrefinder, but this one is absolutely the easiest and quickest to make!

Thanks for the idea. You have my vote!

author
manuelmasc (author)keets2016-12-12

Thank you very much for the vote!! I really appreciate it

author
encicca (author)2016-12-11

Very useful and simple. Thanks!!!

author
manuelmasc (author)encicca2016-12-12

thanks encicca

author
PhilS43 (author)2016-12-11

Variation on quite an old technique, but nice to see none the less.

Circular bar sits in the right angle, 45-degree bisects the disk - rotate the block to get several fixes on the centre point - works every time. The important bit is to get the 45-degree rule to site exactly in the 90-degree intersection.

author
manuelmasc (author)PhilS432016-12-12

old techniques are the best! ahah

author
jeggyboy (author)2016-12-11

I really like the idea of the plastic triangle

author
manuelmasc (author)jeggyboy2016-12-12

Glad to hear that! I also like it because you see through it being sure to place correctly the workpiece in the jig.

author
JohnC430 (author)2016-12-11

Great idea. Not new but a good reminder on KISS.

thanks for sharing

author
manuelmasc (author)JohnC4302016-12-12

thanks for the appreciation!

author
nex_otaku (author)2016-12-11

Easy to make and so useful. Like it!

author
manuelmasc (author)nex_otaku2016-12-12

thanks nex_otaku!!

author
CaitD1 (author)2016-12-11

This always was a problem for me. What an simple solution! I will be making one ASAP.

author
manuelmasc (author)CaitD12016-12-12

thanks! please remember to post your "I made it" photo.

author
Alaskan Bev (author)2016-12-11

I like it - great job; a very understandable and useful DIY tool!

When my students used to want the center of a circle, square, or rectangle on paper or fabric, I'd have them fold the piece (or a pattern piece) in even halves, then fold in half again. One can stick a needle or push pin through the center to mark the real piece of work. If it is not exact to the micron it is still close enough for school art. In working with wood I'd have them trace a pattern piece on paper and use the same technique. I'll be making your center finder, though.

Thank you for such clear directions and photos.

author
manuelmasc (author)Alaskan Bev2016-12-12

Thanks for all the compliments Alaskan Bev! please remember to post your "I made it" photo.

author
Abe Sam (author)2016-12-11

I knew there was an easy way to make a tool to find the center of a circular work piece, but I could not recall it. Geometry does work well on paper, but not very well on a 3/4" piece. This tool is simple and easy to use. Thank you.

author
manuelmasc (author)Abe Sam2016-12-12

thank you for the appreciation

author
Kancal (author)2016-12-11

Common sense--genius

author
manuelmasc (author)Kancal2016-12-12

thanks

author
burnerjack01 (author)2016-12-11

I've often thought "Simplicity is the Art of Engineering".

This illustrates that idea perfectly. Simple. Efficient. Cheaply made. BRILLIANT!

author
manuelmasc (author)burnerjack012016-12-12

That's also my way of thinking! thanks for the comment

author
ozybard (author)2016-12-12

Thanks for taking the time to post this. Simple and effective

author
manuelmasc (author)ozybard2016-12-12

Thanks for the appreciation!

About This Instructable

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Bio: Italian maker, law student, DIY enthusiast. I make lots of projects, I fix lot of stuff and I like to save and reuse materials taken ... More »
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