Low Cost 3D Printer Belt Tension Adjuster

Hi everyone!

This is my first instructable, i hope you find it useful and funny. Its a really simple thing, but for me was a great discover.

Im building a 3D Printer here at Fab Lab Leon (Spain), and i have to adjust the tension of the belts. The main problem is that the model im building is a Rostock Max, so the belts have about 1 meter high (3.2808 ft) and despite i really squeeze it tight before put the belt in the bearings, i use bridle to join the two parts of the belt (as you could see in the first photo, the black plastic part).
So once i put the bridle its impossible to do a fine belt tension adjustemt.

After that i though about print a plastic part with some gears, with a guide or put a piece of MDF with some kind of nut....

...BUT SUDDENLY, when i was hanging the clothes out to dry, i have in my hand a clothespin (spanish: pinza de la ropa) and i see the solution.

Here in spain (and in most part of the world, i suppose), the clothespin is composed by two pieces of wood joined with a small spring in between. Well, lets use this small spring to tension the 3d printer blet.

Well, lets start.

First we need to disassemble the clothespin, having the two parts of wood and the middle spring.

Now take the middle spring and stretch it a bit, until the two arms of the spring form a 120 or 140 degrees angle.

So put one of the finish side of the spring between two gears of the belt (watch the photo below) and, maintaining the center part of the spring in the non geared side, put the other finish side of the spring in between to gears of the belt.

Its hard to explain in words, i hope the pictures help you to get to the finish :)

After placed in the belt, you can make a fine tune of the belt tension by tighten or stretching the spring.

I hope this could help anyone, thanks for watching and see you in another chapter of "im making a 3d printer and my head will blow away" :)