Ender 3 Pro Mod - Y Axis Tensioner

by Cornely_Cool Dec 16, 2018
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Gewindesteigungen passen nicht zueinander.
Musste meine eigene Schraube und Knopf machen

Bett 235x235 fährt gegen den Körper, musste die Größe verkleinert werden auf 225

Sorry, einfach den Kopf einschalten wenn man so etwas designt

Thread pitches do not match.
Had to make my own screw and button

Bed 235x235 drives against the body, the size had to be reduced to 225

Sorry, just turn on your head when you design something like that

Easy easy,

after your post, I've checked the files just to be sure...but as you can see in the attached section, the threads are matching together...
and still clearance between teeth!, so, seems the mistake must be located between the chair and the printer...

I am preparing models for several printers that I didn't own, just to make a favor to some users that ask it on my other projects pages; unfortunately I cannot test my own the models because I don't own all the printer models, and eventual modifications are done according the feedbacks I receive from the beta test users...
Some users give useful feedbacks on the models, so eventual mistakes can be corrected, several others just print and the only comment is "is not working" or similar comments, without read the notes, the specifications, or check if somebody have already print successfully the model...
...so the fact that you write that I need to turn on my head when I design, is really inappropriated and impolite....

Anyway, luckily, Thingiverse is full of other models of tensioners, so have a nice search...

Yea I brought the stls into C4D and theyre perfect... like super perfect. If printed in PLA the contraction from cooling makes them lock up. Didnt have the same problem in PETG though. I cant remember exactly what I did now but I selected all of the inner mesh points of the knobs thread and scaled it to 102% in the X and Y axes while leaving the outside dimensions the same.

if you print in scale 1:1 must be ok! if the pieces are not fitting together, your printer have some issue...

If there is clearance in the model --> there will be clearance on the print...

Really I don't know how many pieces I've already printed (various test during the design phase), and all are matching correctly without any "shrinking" issue...and I am not "pro"!

Do I need any non oem screws to install this?

I would like to print this Y Axis Tensioner and also your X Axis Tensioner, but would prefer to buy new or optional Bearings!
Can you say my which i must buy for my new Ender 3 Pro? 688z? 608z? or others?

I imagine that your machine uses the same bearing of a CR-10, so for the X axis, the OEM bearings should be F688Z (8x16x5), for the Y axis should be F624Z (4x15x5).

Unluckily I didn't own an Ender 3 Pro, so I cannot confirm you 100%. sorry mate!

Did you also have a Tensioner for the X Axis for an Ender 3 Pro? with OEM Parts?

The one for cr-10 should be good.

That means that the Tensioner from the CR10 works for the X Axis on the Ender 3 Pro, but the Y Tensioner from the Cr10 works not on an Ender 3 Pro?
Do I understand this right?
Sorry my English skills are more bad than good

The x bridge is made by 2020 vslot profile (as almost all the printers with similar structure).
The y frame of the ender 3 pro is a 4040 vslot, while the cr10 is a 2040 vslot, so they are not compatible.

and one more question .. can you use a 2gt pulley for the y-axis?

The screw present in the release is for the OEM bearings.
For a gt2 version, you can try use the same screw as the x axis (gt2 version)

I tried to use the gt2 screw from your x axis tensioner, but it won't fit into the body. I don't think this is a tolerance issue because I'm able to print your x axis tensioner.

I would've taken a shot at remixing the part except I can't open the cad files that you've uploaded (don't have access to solidworks).


Were you able to get it to work with GT2 pulley? I would like to do the same.

I haven't tried to fit a GT2 pulley in this part (only have m3 ones but this needs has an m4). I also tried to substitute the inner part from the x-axis tensioner which supports a gt2 pulley, but that part doesn't fit in this y tensioner.

Unless someone here with CAD skills can remix this for a GT2 pulley, our only option is to use the stock bearings. It's not too bad of an option, I've been using it this way for over a month now and it works fine.

guys, the model has been asked as it is... so, for OEM bearings.

Anyway, I am updating all my tensioners models in order to make them "swappable" (screws), so, probably I will prepare a GT2 version also of this tensioner.


Like an idiot, I printed the Ender 3 version of your design instead of the pro version. Just wondering, will the screw and nut from the original design fit in the body of the pro version, so I dont have to waste material reprinting them, or are the designs completely different?

Any feedback for this model? Maybe with some pics

I ran into the exact same issue as Arti4eveR. His measurements matched mine so I did not bother sending another pic of the same thing. In addition I had a small issue getting the bearings to fit between the arms of the tensioner and had to shave a small amount off of the inside protrusions to get them in without force. This could just be a tolerance issue on my machine but everything else fit perfectly so I think the opening for the bearing may need to be widened slightly. My bearing measures at 10.05mm wide. Great design though! Printing the X-axis version as I write this. Thanks for going through the trouble of designing this for those of us with Pro even though you don't have one in front of you to take measurements from.

Modified as requested! :-D

Ran a quick draft print of the body to check fit. Everything lined up great. Belt is now level above the rail and factory screws can be used to attach to the factory threaded holes in the extrusion. See pic. Thanks again!

Thanks man, you arr faster than me...! Ahah

Anyway, please check if there is interference with the bed frame in fully forward position (due to the new position of the screw, I had to increase the body size, and I am not sure of this point!


In my case, there is no interference. The bed frame stops just before the printed body (about 5mm).
Thanks again. :)

No prob mate, and thanks for the feedbacks!

I have 2 bodys on a final print right now(Always Print spares) so I can't install to check but by holding it in position next to the stock one there is plenty of clearance from the bed. It would not clear the carriage where the belt is attached but I don't believe the carriage comes that far forward and it is notched in the center. I will verify after this print it is done. The pics are about the best I can do to describe what I am talking about while the printer is running. Did you widen the opening slightly for the bearings? I have not printed those parts yet. And if so will that part also work in the X axis tensioner? I had to shave that one as well to get my bearings to fit. If so when I print for this I'll make one for it too.

Thanks for the feedbacks!
Yes, I give a little more clearance for the bearings (just because requested for this model...my other models will remain as they already are...).
Also increased a little the clearance between screw and body, to easier fit.

OK. I thought the screw and body fit rather well together but understand that not everyone tunes in their machines. Have the screws printing now.

Wow that was fast! Thank you! I'll get it printing immediately.

Thank you for your design, I tried it but it did not fit very well.
Fixations holes are not fitting to existing ones.
Pulley is a bit too lower, that's make the belt touching the 40x40 profile.
and finally, the minimum tension setting, is too far from the 40x40 profile that make very difficult to install.
Please find attached a picture of original belt tensioner with measurements I made to help you to modify your design.

Nice, thanks for the feedback mate!
Are the lower screws fixed directly on the alluminium, or with t-nut? Diameter of bearings and screw?

Yes screws are fixed directly in the aluminum profile.
All screws are M4.
Bearing size is 13/15mm outer diameter, 4mm inner diameter and 10mm wide (2 bearings of 5mm).

Modified as requested! :-D

Thank you, I can also confirm that the new model fit perfectly ! ;) Everything is lined up and it work well :)
Thanks again !

Do you have one of these for the x also for the ender3

Yes, for the x axis you can use this one : https://www.thingiverse.com/thing:2854971
Has been done for the CR-10, but the ender have the same X Axis structure.

CR-10 Mod - X axis Tensioner

Thanks I am having trouble getting the screw to slide in the mount had to do some sanding and it was still tight added a little silcone lube and got it working somewhat but very snug fit. Thank you for all the work you do designing these parts.Take note I don't have the pro I put this comment in the wrong part.

Hi, some users report the thight fit issue, but the issue is really the setup f the machine.
There is 0.1 / 0.15 mm of clearance everywhere in the model, so you need a good setup for print the models corrctly!

is there a way I could scale the srew down some looks like that is the proble it is too wide and wont slide in the groove

Mine is set up pretty good i have printed many things and they all come.out great and real good tolerance's. Not sure i tried printing it twice. Nice design but tolerances I think arentoo tight. Glad it works for you and some. But no go for me. Thanks for your time in trying.

This model has the same dimensions and tolerances of the ones for cr-10 that I use... and fit perfectly if printed on a decent setup (sadly to say, but... ). The low tolerance is needed for avoid unwanted twisting movements or vibrations... maybe post a photo of your print, just to see it...

I sanded and trimmed till i got them to fit somewhat then i put some silicone lube on the slide points and got them both mounted. A lot of work but seems to be working fine now.

Is this for use with the stock hardware?