in this instructable i make a plastic circle centre finder out of a trown away piece of plastic.
these centrefinders are great when you need to find a centre pretty fast, but it's flat on something.
this is not 101% accurate, but it very close to it, so for most practices a good solution.
(it all depends on how small you make your centre finder,the more circles you draw, the more finetuned it will be)
watcht the vide to see it in action ;)
Step 1: So, It All Starts With Some Clear Plastic You Find Somewhere.
in my case the plastic was not entirly flat, so i have cut some parts of it untill i got a flat piece of plastic that was big enough for my needs. (the centrefinder can be as tall or small as you like)
Step 2: The Need for Compass
you are going to need a compass for this.
in my case i hace a compass that already has a knife attached to it to cut circles. you could use a normal compass with a needle of blade attached to it too. just be carefull for your fingers.
take the centre,and start to make circles at different sizes. you could use a metric system, or you could do like me and just don't care and keep making circles at sizes of wish.
Step 3: Enough Circles Drawn?
when you are done with the circles, you can cut the circle out with a saw, or even leave it as it is if you like the part of plastic. i made a circle of it just for the esthetics.
after that, take a small drill, and drill EXACTLY in the centre. this is where your pen/pencil/marker will go through to mark the centre. make it the size you need for your drawing tool.
well, there you go. you have a circlecentre finder!
watch the video at the beginning to see how it all works.
you don't need a ton of tools like me. use your imagination and basig tools. it works just as good. only slower ;).