Y tensioner for Anet A2

by olev, published

Y tensioner for Anet A2 by olev Mar 6, 2017
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This is an Y tensioner module that fits Anet A2, Tevo Tarantula and possibly other printers that are using 2040 extrusion on Y axis.

Inspired by Banholm's Tarantula Y tensioner http://www.thingiverse.com/thing:1704100, but I didn't like the size of it... it's HUGE. So I went on to create my own, more compact version, which doesn't share any parts with Banholm's.
The sideplates are same height and just 10mm longer than A2 stock sides (72 vs 82 mm). It has 10mm of adjustment, which is plenty for me.

Print Settings


Anet A2










I printed all the parts with 70% infill and was happy with the results, so didn't try any other options :) With correct orientation all the parts should print fine without supports.


To assemble this, you need 6 pcs of M4x10 or M4x12 screws, one M4x30 bolt with 7mm head and one M4 nut for tensioning, and 6-8 M4x10 bolts+T-nuts for mounting it to the 2040 frame. If you want to use M5 bolts/T-nuts, print with thicker walls (min 1.2) and drill the relevant holes with 5mm drill, should work fine.
UPDATE: Don't use the cheap chinese 16t idler pulleys, they will not last.I'm using 16t idlers in the tensioner, but original flanged 623 bearings would work fine as well. Use the original flanged bearings with a 0.5mm shim between the bearings, otherwise they are too narrow for 6mm belt. Original M3x30mm screws can be used for the idlers, only thing is that they must NOT be tightened, the bearings/idlers must be able to rotate freely, so I suggest using M3 nyloc nuts, 2 standard nuts tightened against each other or a drop of threadlock to prevent loosening over time. I used nyloc nuts.
Easiest is to assemble the inner slide first, then backplate + nut (loosely), then add the sides and mount the whole assembly to the frame.

How I Designed This

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Just wondered if you would share your CAD files for this please. A couple of small mods I'd like to make and I feel it would be easier to cut the sides on my CNC router in some 5.7mm acrylic I have spare (estimated cut time under 4 mins). Converting STL to vector outline /dxf isn't coming out as cleanly as I'd like. Thanks.

Many many thanks, that will speed the process up.

Hey, do you have, or share the Fusion Files? Need to modify it for MGN Rails :)

Nice design, nice engineering
Juste some improvements with PLA consumption ^^

Thanks, it works perfekt!

Where could i find those L brackets you used to mount the frame to the board?

Nowhere, I think, those are my own design, but so simple things that I haven't bothered to upload them. For example those should do the same thing, pretty much: https://www.thingiverse.com/thing:2300758

Bracket to mount 2020, 2040, etc. profiles to table
by jartza
Comments deleted.

Nice one. It helps reducing wobble on Y-axis. Thanks!

What do you use for x axis tension?

This: http://www.thingiverse.com/thing:1780636 very simple, works perfectly.

Adjustable Belt Tensioner/Tightener and Belt Tie (Tevo Tarantula)

How do you get the T-Nuts in there? The stock parts is easy because they are flat.

2 options: 1)Mount them all with screws before you push the assembly onto the extrusion from the edge 2) Leave one sideplate off and mount it like the standard piece (don't tighten yet of course), and then mount the other sideplate.

So what does this do exactly?

It's a belt tensioner, so it.... enables you to easily tension the Y belt. Correct belt tension is somewhat important to get decent prints and the belts stretch over time, so it has to be reset every now & then.
Without any kind of tensioner you have to set the belt tension by releasing the screws fixing the idler mount to the frame, which is both tedious and not precise. Plus it just looks cool of course.