CR-10 Dual Z axis with single stepper. Low cost high precision.

by Caster Oct 5, 2017
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Hey Caster! I wanted to try using this mod for CR-10 S5, do you know what size lead screw and timing belt I would need to use instead?

You would need a leadcrew just a bit longer than the one you have so you would probably need to buy 600mm. The problem might be in finding a belt long enough. Mine is 852mm which seems to be the longest offered by most suppliers.

Would I not need to use a longer lead screw since the S5 build volume is about 100mm taller than the Cr-10? I was also able to find 1100mm belt on ebay. Do you think that would be long enough? If its too long I can always come up with a way to give the belt more tension.

The leadscrew only needs to about 25mm longer than what you have so it sticks out enough to fit a pulley. CR10 leadscrew on mine are 390 centres for the 852 belt add on twice the difference yours would be spaced to get the belt length. Some length could be taken up with larger pulles and you may need a tensioner.

Alright I will try that out, thanks for the help Caster!

Great design, and I would like to try it for my CR-20 Pro (235x235x250 printing volume, Ender 3 like). The only differences I can think of are :

I'll check the CR10 size for you tomorrow. Personally I don't think this mod is needed with your printer. I also have an Ender 3 Pro and have not fitted this mod to it. The shorter X arm correctly adjusted is very rigid and I get great prints.
If you chose to go this route beware there are 2 different type of leadscrew, a 4 start and a single start. The CR10 has a 4 start but Ender is single, don't know what you have. I see no advantage with anti backlash nuts. Gravity will keep the nuts tight on the leadscrew.

Thanks for the reply, Caster. I agree this mod is not really needed as the frame is overall rigid, but I'd like to try it and have the printer at its best , even by a little margin ;-)
Agreed also for anti backlash nuts, which make sense when the leadscrew is horizontal, but not when it's vertical.
As for the number of start(s), I'll check and revert.

The length or the top frame section is 400mm on CR10

Thanks again.

On the CR-20 Pro, the top frame is 330 mm, 70 mm less. So, for the belt, I think it should be 712 mm long : 852 - (2*70). On your link to the banggood shop, they only propose 610 or 852 mm, nothing in between. I haven't found yet a closed-loop GT2 timing belt matching this perimeter of 712, the most approaching I found are 696 and 752 mm. Do you think 696 mm could do the job? Otherwise, I was wondering whether I could do something with a 6mm GT2 open belt that I would crimp, glue, ... Any advice welcome ;-)
As for the leadscrew, the Zsteps/mm is 400. As the steppers are 200 steps/rev, my understanding is 2 revs are necessary for 1 mm on the Z axis. Could you please tell me the corresponding number of starts, as I'm not -yet- an expert on leadscrews ?

I agree with your belt calculations. Are you going with my recommended metal bracket?
With the 696 belt the leadscrews will be 8mm closer which can easily be taken up with a small modification to the bracket.
A 4 start leadscrew like mine will move the nut 8mm per turn. A single start will be 2mm per turn.
I don't think you would be able to use a joined belt. The joint would pass over the pulleys as the Z height increases.

Your support is premium !
I'll go for the metal bracket. Modifying it with the three holes 8mm closer to the existing axis to match the 696 mm closed belt should do the job. After checking, one turn of the leadscrew is 8mm up on the CR-20 Pro, so it's a 4 start one. Hope this information will be useful for someone else wondering ...
As for the joined belt, that's what I anticipated. That can work on X or Y axis, but not on Z.
Thanks again for your support and patience, I will keep you posted.

Comments deleted.

Hi, thanks for this very useful design!
I have a question relating to the assembly.
On my CR10 Mini, the original top left bearing retainer seems to fulfill the same purpose as the printed one and seems to largely share the same dimensions. Is there a reason for using the printed design or can I just keep using the original one?

How tight do you tighten the znuts on the bracket? My printer jumps and bangs are my znut too loose on the mechanic z side

Printer should not "bang and jump around" Maybe you need to sort this out.Screws should not work loose once tightened.

The distance between the centres of the leadscrews will be about 390mm with the specified belt and pulleys. Lots of people have made this mod so I can't see were your problem is.

Well I got the parts listed and the belt is WAY to big for my CR-10 with the 36 pully . I even tried with GT2 50 pullies and it's still way off ,

I guess since both lead screws just go through the pulley the original length lead screw should be fine for any machine so I'll stick with the original size and get the parts ordered. I have the dual z-axis upgrade but I'm not convinced both motors are in sync and I'm getting a lot of z wobble. Hopefully, this fixes that problem as it has for many others. Thanks for the reply and the design

are the parts list correct for a cr-10 mini? I would think a shorter lead screw but everything else should be the same?

I understand the mini is the same but not as tall so all parts should fit. You can buy a shorter leadscrew,

Definitely going to try this out once I get a second lead screw. Just one question, though: Is this compatible with the new cr 10 models? After some reserch, I found out that I do have the newer version, and I just want to avoid making a rookie mistake. Thanks.

The left hand top bearing may be different in the newer models.
At the worst you will just need a new flanged bearing to rplace the existing. see also the comments below yours.

Is it just me (TM) or does the LH Block retainer plate and the LH block not really fit together? The diameter of the cylindrical part of the plate is too large in diameter to actually fit into the hole of the block and it is also too high to make sense to me? I measure about 4,2mm distance from the bearing top to the top of the LH block, but the retainer's cylinder is about 8,3mm high. So I wonder if I missunderstand which parts belong to the left hand block or if there is a mistake in the files?

I am talking about Z_axis_LH_block_v2 and Z_axis_LH_bearing_retainer.v2

Other than that, thank you for this great and simple idea!

This could be due to a change in Crealty design. What is the size of your bearing. I'll look into the issue.

I actually already have trouble putting the two printed parts together. The cyclindrical part of the bearing retainer should obviously go "downwards" into the block so that the cylinder pushes the bearing against the seat within the block - right? If so, then the cylinder wont fit into the block here - is is too large in diameter to go into the "hole" of the block. Or is the is meant to be the other way round, so that the cylinder part of the retainer faces away from the block? I thought the idea was to have a way to lock down the bearing, but maybe the idea is that the bearing can float in the block?

Sorry for the confusion but thanks for the quick reply :-)

I checked the drawings and cannot see a problem. As you say the cylindrical part goes into the block to hold the bearing. The hole in the block is bigger at one end and that's the end the cylinder fits into of course.
I think others would have brought this up if there a problem, I know a lot have been made.
I don't suppose it's this but you did print both out at 100% size and not made one smaller by mistake.
If you cannot resolve I'll print another and check it for you.

...that was what I thought initially - if something was wrong with the files, someone else must have noticed before me. So it maybe has to do with opening the files on my computer or whatever. My solution was now to rework the cylinder in Fusion360 and now the 2 parts match. I attached a screenshot of Simplify3D with the 2 original parts loaded and aligned to how they should probably fit together and using a crosssection view you can see that the (upper) retainer's cylinder section is too wide and also too high (to leave enough room for a 5mm tall bearing). Really strange!

Glad it's sorted. Note my bearing is flanged most of the bearing is below the surface of the block. It could be later models have a different bearing.

About to try this out. Had to edit the blocks to accept fidget spinner bearings though. They're just a little bit bigger than the ones you used I guess.

Dude ... honestly - you need to sell this as a kit. Amazing idea and simple. I just paid $169 for Creality's official Dual Z upgrade kit. I would have purchased a said kit over the official upgrade

Comments deleted.

hi caster sorry if i'm being a pest but them two screws that go underneath the lead screw nut how tight do they need to be? just im getting abit of layer shifting, do i need to change the voltage of my stepper now that i use a dual z?

Plenty of power in the stepper no need to change anything.
Screws should be tight. The layer shifting will be another issue not related to this mod.
When I first had my printer I had layer shift and it was traced to the extruder being loose on the carriage.

top right block when you use the tnuts to tighten the belt it pulls my belt too much to the right which leaves my wheels not getting grip on the aluminium extrusion

Comments deleted.

If this is happening your left hand or?and right hand bearing must be moving in the block. it should be unable to move in the X axis.

caster, the bracket that attaches onto the xbarwheels how tight do you do them screws on it which moves the bearing i left mine very lose as i thought it needed to be?

The bearing has to be fixed in the blocks so it does not move, the blocks are fixed tight to the aluminium frame.
Tension the belt whilst tightening the right hand block and the adjust the position of the new leadscrew nut so the leadscrew is parallel to the frame in both directions. Watch the video again.
it also sounds like your wheels are no adjusted correctly you should not be able to pul them away from the frame.

top right block when you use the tnuts to tighten the belt it pulls my belt too much to the right which leaves my wheels not getting grip on the aluminium extrusion

hi my stepper is way too low, i do not believe the cr-10 came with a 600mm leadscrew as it's so short

The new 600mm leadscrew replaces the existing to bring it above the frame so pulley can be fitted. Existing screw is reused on the right.

Installed the DZSS yesterday (with printed bracket). Really easy to do, works fine so far - will go for a high model for comparison next. Thx a lot, Caster - parts, tutorial and the overall mindset of this mod is just great!

which files i have to print?
And Thanks 4 sharing you construction! Looks very good!

If you make the recommended metal bracket you don't need the either of the 2 printed bracket files. See my description regarding which printed bracket to use if you need it.

Thank`s a lot Caster!
I print all parts with PETG an 20% infill.
For me, the bracket is a little bit to flexible. So i print this part again with 80% infill witch is mutch stronger.
I put some 0,5 washer betwen the bearing and the bracket.
Also i have to tunraround the screews


i have already the CR-10S with dual z. Is it not possible to make this mod with the original leadscrews, by just buying the pulley, belt, coupler, printing the parts for the left side but just place the upper printed part (block) a bit lower to the profile? That would mean, i will loose some cm in z height but i can use my original lead screws.

The right hand block is mounted on the horizontal rail and and can be moved to tension the belt. if you mount it on the vertical member there is no way to tension the belt.
Don't be a cheapskate get a new leadscrew.


thanks for the fast comment. Its not about the money, its about time, i will have to wait 3-4 weeks for the new lead screw.

Comments deleted.

A little update on the cost of materials needed for 2018: Price for required components now closer to £20 shipped.

Still very cheap either way, and far cheaper than scambay.

Has anybody tried this upgrade with the printed pulley that's linked in the description? If so, does it work more or less just as good as the aluminum pulley?

i printed some for other projects before, be sure to print them with 100% infill and as precisely as possible.
I did mine with 0,1mm layer heigt and a 0,25mm nozzle, they still work perfectly, even PLA.

Single Motor Dual Z screws are worst than use one, right? i was ready to print this mod, but read that is possble to get a lot of Banding and wobble,is that right?

Everyone who has made it has been delighted. Don't know where you read this.

Ok, then will print it! I read that is just better to use two motors instead one!
Thanks for reply

You have it the wrong way around. 2 motors can get out of sync and cause problems. One motor cannot, mechanical linkage cannot slip.

Thanks too much will test it then !

Hello, i did not found screws for mounting RH Block and i remixed with other design. Thanks for this great design.


CR-10 Dual Z Axis RH Block
by emroah

Will there be any long-term issue if I print this kind of upgrades with PLA?

i have alreasy bought the dualz upgrade and want to do this i dont need to make the metal part do i ? or just print it? any help would b great i do need to do this cause mines always gets out of sync and i need to fix this

You will need to make the metal bracket or do the printed one. The one in the conversion kit is different.

Hey, will a 500 mm lead screw be enough? I can't find a 600mm one that ships from the eu. Don't want to wait for order from china. Thank you.

You need 600mm , 500 is too short.

Thank you very much for this design and the helpful video. I just installed it today and it seems to be printing just fine. My 20mm calibration cube was perfect on the z axis and will print taller things to really test it. My single Z was already well tuned for high prints as I've maxed out the height on prints before but I always felt that a single screw was not stable enough.

I had some trouble with the printed blocks being too small for cap head m5 screws, I even tried expanding the size of the countersunk holes in the STL file but could not get them large enough without cutting into the bearing holes in the center. I ultimately went with some pan head m5 Philips screws I found which worked fine.

Also the printed bracket was difficult to secure to the X axis gantry as there was not enough room to fit a wrench or socket in the back. I was able to just jam a wench tip in there to lock the nut enough to use the hex wrench on the screw.

Thanks again for this design and material guide, it made it easy to find and buy the parts.

Love your simple design. I appreciate your mechanical understanding and a top notch solution to the Z binding with a minimum of parts. I use it on all my large format single Z printers.
Thanks for the solution.
Dave Petsel

did you add some additional parts on your T8 screws for tevo tornado ? if yes can you send me those files ? need to make this upgrade tomorrow

It's great that we both find each others designs useful. Thank you for your brilliant fang for the CR10.
Caster, AKA myfordboy

Does anyone with this mod have any issues with Z stepper overheating?

I just noticed mine is getting unusually very hot, while the other two keep relatively cool.
I just want to check if its maybe something in the firmware - since i got the motherboard upgrade and put in new firmware for CR10S.
Or maybe its a common effect, maybe caused by Z stepper moving two axis now.

I tried lowering the voltage on the motherboard potentiometer but it doesnt remove the overheating effect.


Anyone running this mod and had upgraded the motherbord to v2.0/1 and new firmware?

I can't see how this mod can cause overheating. The steppers have plenty of power and the Z axis hardly move compared with the X and Y. Mine run very cool.

Yeah, i would think so too, logically.
Im only asking so i can remove possible options and so figure out whats causing this.

Could be the firmware for CR10s has something extra enabled for two steppers those use, although there is only one connection on the motherboard... and i just solved the bad capacitor and another serious problem.

Wait,... i just opened some pics of the motherboard i had from before, and on one of them there is an extra notification for the Z stepper connection... "if only one" it says... and points to a second slot. Maybe its that.


Seems like that was the issue. It took some more fine-tuning the potentiometer but it seems its heating up less now.
Gone get something printing and see what its like after longer use.


Nope, same.
Ill replace the stepper, ... probably with an axe...

its ok for tevo tornado?

Trying to put this together but bang good is not good. The lead screw they sent me is bowed. Seems like this a common occurrence!

Same here. I just went back to my duel Z I originally had because of this. If your going to do this mod, dont go banggood. Cheap prices for cheap parts.

Does the other lead screw just hang off the side? It looks like it when the bottom is briefly shown in the video?

Yes no support is needed at the bottom.

Thanks for the reply! I am new to printing and it seemed kind of sketchy when I saw it at first lol

Hi Caster, I ordered the leadscrew from banggood and received a severly bent screw. After reclamation they sent me another one which is still not totally even (maximum displacement in the middle of the screw is approx. 0.5mm). Do you think this is too much or still ok to use?

I would try and straighten it. Rest the ends on blocks with the high part of the bend at the top and push the centre down. It probably does not need much pressure. Practice on the first bent one!

I've notice an issue when using M5 cap head screws other than the ones shipped with the printer. It seems the heads are lightly larger in diameter by about .8mm. the bosses for the screws fit the orginals fine but any replacement screws are a no-go unless the holes are slightly larger. Anyone else had this issue?

Swap your new screws with some from the printer, job done.

Yes I have the same problem and NETWORXnet had it too. I will either drill the holes bigger or heat the screws for melting the plastic a little.

I've created modified STL files that will allow for the M5 cap head screws. I'll be glad to share or post them is desired. I think this issue may be unique to certain manufacturers of the metric cap head screws.

Can you publish your STL? I had putted the project beside because of other important thing but want to start over. Thanks

Has anyone experienced a marked improvement with this mod? It certainly seems really sound, but I'm just curious what people's results have been. Thanks!

Seems very well built!
Maybe a silly question, but i'm new to printing and will be recieving my first printer shortly;

Can i do this mod on the Cr-10 Mini as well?
Obviously the leadscrew probably has to be shortened, but other than that?

It should fit the mini fine as the X dimension is the same as the CR-10

Thanks! I'm going to try it!

Have you done it yet? How did it go?

The bracket on the left does not need to be made. I took the old (shorter) screw out of the left and installed it on the right and used the longer one on the left. Check my account, I have a very simple belt tension setup

Well - did the mod and it was easy and worked fine. I looked at the printer and realized that you COULD use the existing mount on the left side...and I did. You don't need to make a new mount.... just use it and nothing has to be adjusted on that side or changed... check my pics in my make.

There are 2 different top bracket designs. Mine had a bearing that could float in the Y direction so it needed to be fixed. |Maybe the newer ones do not.

Trying again with new lead screws. The first leadscrew from banggood was all kinds of bent. To clarify, you're using the shorter old leadscrew on the right side, using the pulley at the top, and the coupler at the bottom of the bracket? This keeps the screw from moving up or down? The video was unclear about this step.

Video is quite clear and shows it at 13:00. You do not shorten the existing leadscrew but reuse it on the right. New longer 600mm screw is shortened and used on the left.

is cutting the existing rod to 535 necessary?

The existing leadscrew is shorter than 535mm and is used as it is.

so the NEW one is 535....

Correct.You can leave it 600mm if you like but it will stick out of the top.

I have had your upgrade on my machine for several hundred hours of printing. I can't tell you how much I like the simple engineering of it. The fitment was perfect and parts printed well and fit better. Had to pay about $30 for all the parts because I was in a hurry to get it up and running and couldn't wait for Banggood to get stuff back in stock. Great work Caster. There are so many Rube Goldberg designs out there. It's enjoyable to have some real seat of the pants engineering that makes a difference.


Thank you for sharing an awesome design. I have finished the upgrade on my Creality CR-10 and it is working great.
I used all of the printed parts.


Mike Lib

This is great, thank you, Ive ordered the parts so planning to have a go at putting it together as soon as they arrive. Have you considered selling the brackets? Having them in sheet metal sounds like a much better idea but I don't have the facilities (or as yet ability!) to work sheet metal accurately here.

People would not be prepared to pay the time spent in making the brackets unless I had a batch laser cut.

the lead screw on cr-10 is that single or 4 start?
I’m going to put this on a Tevo Tornado, and it has 4 start lead screw.
should the new lead screw be single or 4 start?
just want to make sure I get the correct one :)


The one I gave the link to is a 4 start. You have to have both screws the same so you want 4 start, one turn moves 8mm.You could check this with a ruler on your printer.

Hi, the bracket won't fit my new CR-10. Distance between the mounting holes too close.

A new has been uploaded.
Strange, the comment below your states the bracket fit was very good.

Printed brackets fits very good. Had no problems getting this togheter. Just selected the screws that fit. I have a good selection of screws, washers and nuts. I did not use the coupler to fit the new lead screw. I did not like the downward springiness it gave.

Thank you for the feedback. The coupler is not used as a flexible joint only to locate the bearing. See the video. I recommend fitting this or a solid one as without it the screw is not captive to the bearings in the top block.

I understand. Will fit something rigid. Thanks!

My prints are PERFECT. It was good before this mod too but it did not feel right. ;)


Have you done any test prints yet; any difference? I've been debating doing this mod or https://www.thingiverse.com/thing:2668969 with the braces.


Dual Z & Frame Braces for Tevo Tornado and CR-10. Low cost high precision
by pemic

I got great prints before and after the mod. It's just a better engineered machine now. Personally I don't think braces are necessary as the frame is pretty rigid.

Ok thanks for the info. I think i'll go this route then. Would using the 3D printed pulley parts be ok vs. the metal ones? Only asking because if I can save a few $$$ I would like to.


I would go for the metal pulleys. 2 only cost $2.50

Thanks for the nice draft.

Unfortunately, after buying and printing the parts, it seems some of the holes in blocks/retrainer and screwlength won't fit.

Holes in RH Block are to small (8mm) and won't fit the DIN912/ISO4762 dimensions. Base on DIN/ISO M5 hexagon headcap screws have 8.5mm headcaps, 10mm countersink and 5.5mm holes (M3: 5.5 / 6 / 3.4).
Seems dimensions are more made for M4 screws?

Screws for the printed bracket needs at least to be 18mm long and for LH block 20mm

It is a bit annoying, often realizing drafts have errors after printing cause you only have the stl files. Would be nice and very usefull if sketches would be additionally uploades more often, to have an better chance to check dimensions before.
I'm repeatedly surprised, that some things (drafts) have lots of comments and mades but no helpful comments about problems or details that won't fit. Like you said, that nobody give feedback if the printed bracket will fit.

Is it possible to edit the draft or can you provide the sketches?

Dear Caster,

why you have deleted your reply?

"Caster posted a reply to your comment on CR-10 Dual Z axis with single stepper. Low cost high precision.
I have checked the screw length. The ones I used were defiantly 16mm long, I don't have any other lengths in my stock. I will upload a new STL file later to suit the M5 screws."

I think the screws are to short, because you use the steele sheet holder (appr. 1mm) and i/we use the printed one which has an thinkness of about 3.5mm. So 20mm should be fine with the printed part.
Alternatively you can countersink the hole in the nut block for about 4mm.

What do you think about my suggenstions?

I deleted the comment because the information was incorrect as M5 is the correct screw to use in the blocks.

Hmm, but screws and holes not fit ... see picture
Holes to small or M5 screws to big? ;)

Do you have other (non-standart) M5 screws or uploaded different stl files?

It seems your heads are larger than mine. Did you not see my reply of 2 days ago. The block that is in the front of you picture uses the smaller screws and tee nuts that held the original block. All you need to do on the other one is drill out the holes to suit your screws.

Comments deleted.

Thanks for your quick reply Caster.

I think previous quotes are not clear in that point and very confusing. There are serveral posts here, on your blog and youtube channel where is stated to use M5 screws or bolts explicit. Far more times then an hint that M4 could be the right dimension ...
Either descriptions are not up to date or the STLs???
As stated before, using M4 screws alone will not solve the problems as the given screw lengths are to short and you also need M4/20 T-Bolts then.
II think it would help people to update all your descriptions on myfordboy.blogspot.de, youtube and here with the right dimensions. Find the relevant places in the screenshots below.

For me personally, it would be helpful if you cloud provide the sketches to edit them for M5, as i already have buyed the needed parts.

I was going to update the STL file but on checking found it to be correct.
The RH block screw holes are 5mm with an 8mm counterbore which fitted my M5 screws fine and others I have in stock.
I have checked the screw length. The ones I used were defiantly 16mm long, I don't have any other lengths in my stock.
If you have screws with larger heads why not just drill out the block to suit?
The screws used on the LH block are the ones that held the original block.
I did not quote a screw length to use if the printed leadscrew nut bracket is used because I did not use this but included the file for anyone that could not make a metal one.

I wish I could make a steel bracket...i have all part and printed all pieces just was wondering about the gear. I'll just have to order it and wait it out. Thank you for the quick reply and assistance

Does the tooth count make a difference on the pulley? I can find a 40t but the 36 is hard to find without waiting a month or so to get it

Using a larger size pulley will bring the new leadscrew closer to the frame which does not matter but the bracket that goes on the X carriage was designed for the 36 tooth pulley.
There may be enough adjustment available. If you are making the steel bracket it's just a matter of moving the holes in the top a little.

great design - printing now and I wonder if you could add frame strenthening to reduce vibration?

Thank you very much for this, just a novice but give it a go

I have a question: Why is it important to use a 36 teeth pulley and nog a 20 teeth?

20 teeth would move the leadscrew too far to the left.

Could have been made simpler and better ! Indeed, one leadscrew + coupling work in compression, the others in tension, the flexible coupling can induce wobble and are in fact unnecessary, no easy way to tension the belt, vibration etc....
The original idea can be found here: https://www.thingiverse.com/thing:1830451
Easy to adapt.

Prusa Z axis, so many problems yet one simple solution !

You do not understand the design. The flexible coupling is only used to hold the leadscrew between the bearings. A coupler could be used instead. There is no issue with one screw in compression and one in tension as the right hand leadscrew is directly coupled to the pulley.
The belt has a 180 deg contact on the pulleys for best power transmission.. The belt does not ever need tensioning once initially set up.

I understand your assembly, the errors and useless complexity. The flexible couplings of course allows radial misalignment which your system has. Gee, it is the way you try to tension the belt !
Fact is, a correct design would be simpler !

I think you still fail to understand the assembly, watch his video and you will realize where you are wrong. The coupler is NOT being used as a coupler, as Caster has already told you, but I guess you didn't take the time to read his reply to you. The coupler is being used more as a collar, to prevent movement in the threaded rod.

Please take the time to read and investigate the reply to your own comment before shouting back. Don't see the need for all the exclamation marks.

Just explain how he tension the belt then ?
Again, can be made simpler AND better.
Anyway, I let you play, kids.

He tensions the belt by moving the complete assembly of the secondary z-axis, keeping everything in line with no mis-alllignment. Once again, if you would take the few minutes to ACTUALLY look into the assembly and function of this (as you said you did, but it is apparent that you did not), you would know. It's about as simple as it gets. Try not to use other people's useful creations to advertise your own.

Indeed, as I saw. Totally stupid !

Oh yeah, there is a video to show you how to drill etc... Geee !

What I did was one year before this. I don't claim he copied my idea though as one motor to drive 2 lead screws is what real engineers do but not the insane way this guy did.
May be Prusa compromised to produce a kit any idiot could put together.

This remix just proves my point, yet could be simpler by putting the motor instead of the idler. https://www.thingiverse.com/thing:2668969

Sad to see how Thingivere is going down the drain.

Dual Z & Frame Braces for Tevo Tornado and CR-10. Low cost high precision
by pemic

Now that you see your original comment was wrong, you result to insulting his instructional video?

You say that the way you are suggesting is more simple, yet to do it that way you have to (in addition to what this design includes):

  1. design and print a whole new motor mounting bracket
  2. physically move the motor to the top of the printer, which would require a person to extend the motor wires. A lot of people here do not have the proper equipment and soldering skills,
  3. Print more parts than is required by Caster's current design. Namely the motor mounting bracket, and would probably require a re-design of the existing hardware on the side where the motor once was.

Not only is it more complex, but you are moving more weight to the top of the z-axis, which some say can introduce printing artifacts. I have never tested, so I am not absolutely sure of this. But, it could require adding additional braces to the frame, and thus, additional complexity.

I never stated that his solution to adding an additional z-screw was the best, I was merely trying to point out the error in your comment, so others would not be mislead when browsing through the comments. Additionally it is just bad form to immediately point out perceived flaws in someone's design when you do not understand it yourself.

My initial comment stays valid.

If to make a new motor mount (the guy here made a new one BTW), extend the motor wires.... is too much for you then your comment is irrelevant.

Motor at the top, an issue ? What about the people mounting the spool at the top ?
Besides looking at your poor things, kid's stuff, I wonder what kind of "professional" you are.

The CR is a piece of junk anyway but can be made usable. The first thing being to make the frame more rigid, then do what I suggest.
Some guy already made a remix by adding a pulley to adjust the tension. The next step, just replace it by the motor. "Et voila" ! :)

So, my comments are for smart people who CAN. Other's, I don't care.

I bet you're a load of fun at parties too.
Go away or change your tone, it is obnoxious and I doubt anyone is listening to you.

Just wanted to let you know that the big part you did in metal but can be done in plastic is fine when printed out and works very well.
I did it in PLA, 30infill, and have just set up everything today. It turns out much nicer if its flipped so its long thin side is up when printing.

I used only one block for the right side, kept the existing one where it was.
Got all the parts through your links except pulleys which i found on ebay.

Thank you for a great design, links and a how to video. I had a lot of problems with the x gantry right side although i tried balancing it many, many, many, many, many ,many, many, many times.

One question just to be sure:
Does eccentric nut need to be as tight now? I kept it lightly tightened just in case

Thank you for confirming the printed bracket works OK. I have asked others, they are happy to take the design and ask questions but can't be bothered to answer mine.
I would adjust the right rollers to be not tight whilst making sure all 3 wheels turn when the axis is moved.

I have noticed nobody confirmed it is alright, or not, neither at youtube, here or on your blog. So i made sure to at least do that for you.

Again, thank you very much, this will enable me to actually create a prototype for my project ive been planning a long time.
And thanks for the advice on the wheels tension, i assumed something like that but wanted to be sure.

Hello everyone,

Since my CR-10 was factory upgraded with a LH block, is there any reason I can't use it?

So I would only need to print the Z-Axis Right top block and the bracket, correct?
With the printed bracket does I still need the nut block and retainer?

Thanks in advance,


Both blocks need to be able to clamp the ball bearing to enable the belt to be tensioned.

Caster, thanks for your fast reply!

If you can see from the youtube video, there is already a ball bearing on the original LH block, and it only wobbles in the Y direction, so it will allow the belt to be tensioned by the right top block.

And what about the nut block and retainer, if I use the printed bracket?

Thanks once again!

You need to stop the bearing moving in both directions. Mine is different to yours but it looks like there is a plate that covers the bearing block?
You could clamp in in place by adding a thin card washer above the bearing. Make it the outside diameter of the bearing and make the hole larger than the inner part of the bearing so it will still move.
Before clamping it up move the Z axis right to the top so it is aligned. Also check it is aligned in the Y direction and adjust it in the top horizontal frame if necessary. Before doing this its a good idea to see if the Z stepper is correctly aligned with the leadscrew nut when the Z is a t the bottom of the frame.
My bearing was flanged is this the same on yours?

Hi Caster,

Yes, the bearing is flanged, but the part is now made of molded plastic and it does have a plate cover.
In the CR-10S (dual z) they even use on each side one of these blocks, thus I am thinking that I will only need to print the necessary right block and try to test on how this clearance movement from the original Z top block allows to correct any alignment imperfections from the Z rod (only in Y direction) without any issues with belt tension.
To the right Z top block I will definitely print your model .

I build one from your idea but with own bearing holders also with a foot-bearing. I use a spring for tension the belt, Works great and the difference between left and right side is about 0,01 to 0.02 mm. Great solution. Thanks a lot.

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The lead screw is out of stock from Banggood. I found this part from Ebay. Can you help and confirm if part it correct?


Yes that one looks OK.

Thank you very much.

I like this way better than the two motors solution from my CR-10S, yet.... It doesn't seem to be an easy way to accommodate the right carriage so both ends of the X beam are at the same height from the bottom frame, other than loosening the pulley at the top... am I wrong?

You set the beam to the correct height by adjusting the position of the pulley on the right as you say, but only have to do this once it will never need adjusting again.

Thank you very much for the time you put into this and for sharing! I didn't see the bracket in the pics of the .stls. It may be there, but I'm not on my computer. Is this included or in a different upload? Didn't see any other link to thingiverse on your YouTube video... Really looking forward to making this happen! Thanks again! And by bracket I mean the one you made of metal in the video...

EDIT: Got to the computer and saw it was included with the files, just didnt have a pic! Thank you once again sir!

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You are obviously much smarter than me but it's you that's wrong.
The thread form is 4 start 2mm pitch which gives a 8mm LEAD.

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Me and a friend were just devising a way to have dual z rods with one motor today, few hours ago and i go online and run into this. Excellent job sir. Thank you very much.

I re-verified the BOM, and calculated from the different parts via SolidWorks, seems like your BOM is a bit short, here are my results :

  • 2 x M3 12mm screws for LH block (2 washers here)
  • 2 x M3 18mm screws for Printed bracket (and 4 washers here)
  • 2 x M5 18mm screws for RH block
  • 2 x M5 T-slot for RH and LH blocks (we need a total of 4 but on the printer we have already 2 of these)
  • 4 x M3 nuts
  • 1 x 852mm GT2 belt
  • 1 x 600mm lead screw D8 2mm pitch
  • 2 x pulley 36 teeth 8mm internal diameter
  • 2 x bearings 688ZZ
  • 6 x M3 washers

On Aliexpress and a french screws supplier I got a total of around 20.50€ + 7€ of shipping

Edit : I didn't put the flex connector and the M8 washer because I think they're not necessary. If you plan to take this printer in low gravity environement it could be an issue but I don't think anyone will send a CR10 in space :-)

Flexible collar or a rigid one is essential. Without it the leadscrew would rise without moving the right hand axis when Z axis is going down.

Are you absolutely sure that the stock lead screw is 2mm pitch and not 8mm? I'm getting different opinions from the FB group and other forums.

It's 2mm pitch but has a 4 start thread and an 8mm lead so you get 8mm travel for one revolution of the screw. Use the link provided and you will be sure to get the correct one.

Just printed this all out and everything seems nice, but for some reason the Z_axis_LH_bearing_retainer does not fit into the Z_axis_LH_block....

I measured the drawings and the bearing retainer seems to be over sized.... its about 18.75mm while the hole on the block is only 18.4mm on the narrow side so I had to file it down to make it fit, the weird thing is I don't understand why nobody commented on this? Or am I making a mistake?

There does seem to an error in the dimension so I have redrawn the LH bearing retainer and updated the STL file.

Excellent thanks for clearing that up, thought maybe my machine was over extruding or something lol thanks for the quick update!

alternative z motor collet move up 1cm on stock side mines pushed all the way in making the alloy shock thing pointless as its resting on the motor shaft you then have enough room to mount pulley

ive a spare creality shaft for the other side just awaiting belt.
Balls i should of looked in the post box !
thank you very much

Thanks for sharing your idea and files!

I'm going to do this mod but I'm not shure about the lead screws.

Do I have to purchase two 600mm lead screws (one for each side)?
If I understand your instructions correctly, the existing lead screw of the stepper motor has to be exchanged by a longer one (535mm), correct?

What about the other side? I assume I need another lead screw of the same lenght (535mm).

Could you please explain?

Thanks a lot in advance!

The new leadscrew is shortend to the length shown and replaces the existing one.The existing one reused on the other side. This can be done as the new Z axis screw does not have to reach right to the bottom. Make sure you get the right leadscrew as specified. There are some with the same diameter but have a different pitch.

Thanks, Caster!
Now I got it.

Great Design, I definitely have issues with my dual z axis getting out of sync about every 10 prints of so.
What size belt would be needed for the S4(Which is 100mm wider)?

The outside frame measurement on my 300x300 printer is 400 and it uses a 852mm belt. If yours measures 500 than you would need a belt 1052 long, if there is such a thing. It need not be exactly that length, you could make the metal bracket dimension to suit one that is close.
If it were too long an idler could be added to take up the slack.

Thanks for the information, I'm going to try to splice my own belt with this https://www.thingiverse.com/thing:1814419
This way I don't have to make any custom brackets and should work withe standard dual z kit.

GT2 Belt Splicer


What length is used for the M5 screws ?

16mm as shown on the build instructions.

Hi Caster,

I follow you on YouTube and am a big fan of your work. I currently have the dual Z-motor upgrade kit installed and so far, I haven't faced any issues with it. However, I installed it prior to doing adequate research into the potential issues and am now considering switching to your setup.

It looks awesome and I can't wait to try it out.

Thanks a ton for the post! Great stuff!

where do you get the t-nuts for the bearing guides?

Hi. This are m5 you need m4 as written in guide.

I have edited the guide. It should be M5 screws and tee nuts but M4 will work OK too, may need to add a washer under the head.

Just a heads up on this project. Beware of ordering the leadscrew form other than the link given. There are 2 forms of 8mm leadscrew available.
One is a 4 start thread that gives a 2mm travel for one turn, the other is single start that would move the nut 8mm per turn.
The details are not given very clearly on some sites. I made the mistake and ordered the wrong one to start with.

Isn't the opposite to this true? 4 start gives 8mm travel and single start gives 2mm travel??

I got the wrong one too, changing the number of steps/mm in firmware or using M92 Z800 (in my case I got the 4mm / rotation T8 rod, hence the 800) will fix the issues. Hope this helps anyone who gets the wrong T8 rod. Only thing is you need to replace the existing one too. I was lucky because I ordered 2 T8's/.

Which lead screw is required then? The 4 start or single start?

You need the 4 start. i recommend ordering it from the link i gave to ensure you get the correct one. Some descriptions for similar items do not mention if it is 4 start or single start.

Very nice! You have the 500mm CR-10? if so that'd make sense why you marked it at 535mm?

No, I have the standard. 300 x 300 x 400 printer. The screw is longer than the print area.


Love the metal break! Great work.

I'm on the fence on this project as I simply can't find any fault with the single leadscrew CR-10. I have the second leadscrew upgrade kit, but haven't installed due to all the sync issues I've been reading about. Now I don't know if I even want to worry about. In your opinion, has it made any difference in the quality of your prints?

If I do decide to add a second leadscrew, I'm going with your design - it's simple and ingeniously fool proof with respect to sync.

Either way, I now have an extra stepper motor, leadscrew, and control box so maybe I'll fabricate my own CR-10 from parts.

Thank you for taking the time to make an excellent video and for sharing your design with us.

Again, nice job!

My prints were fine without this mod as I stated in the description but mechanically this has to be a better method of driving the Z axis.
It can do no harm .. Not sure about the 2 stepper mod though.

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I saw it on youtube. You are a subscriber. Nice to meet you.

Awesome work!
I ordered everything from Aliexpress because its in stock:
https://goo.gl/nRRM3K 1x 600mm / Leadscrew + nut
https://goo.gl/6gS7hH 1x 852mm / Timing Belt
https://goo.gl/ijhgZM 1x Pack / Bearings
https://goo.gl/1dTJh7 2x 8mm / Timing belt pulley
https://goo.gl/cmxKwd 1x 8x8 / Flexible Shaft Coupling

                               $15.65 Total inkl. Shipping

That's the wrong leadscrew, you need a 4 start thread.

The illustration on the Aliexpress link looks like the wrong one to me. It looks like the single start thread. You need a 4 start thread. I made the mistake myself and ordered the wrong one to start with.
Use the link I provided to make sure you get the right one.

Thats exact the same leadscrew when compare the spezification.

Quick question. You specify "GT2 858mm Timing Belt" but the largest they list is 852mm from the link you provide. Is it 852 or 858? Thanks.

Sorry my mistake it's 852mm. I've corrected the text.

Excellent work, caster.
I was Considering adding adding a manual Z axis knob to my cr-10
and see that you at one time did as well.
You could have left the extra length on the new leadscrew and designed a new knob, but didn't.
Did you leave this out because you didn't find it useful,
or do you think this may cause misalignment issues?

Yes I had a knob fitted before this Mod. It's not needed now for two reasons. I am using Printoid pro App to control the printer so it's very easy to move the axis and if I want to do it manually i can just pull on the belt for a quick travel.

This is I was seaching for.
Great job :)

how is the second lead screw fix on the bottom?

nice work!!!

It is not necessary to have a bearing on the bottom of the leadscrew. The existing one only has a bearing at the top to stop it wagging about.

So the other end is Hanging in the Air , right?

Correct. To support it would introduce another potential misalignment and is completely unnecessary.

Caster, you're missing out on $. You have a potential goldmine. Why? I ordered and installed the dual axis kit from Tiny Machines. It's a great kit, but.....even with the second Z axis motor/lead screw, the two motors act independently, which continues to keep one side of my horizontal bar uneven. I have to, before each print, re-measure to keep them both level before leveling the bed. Your design continually keeps the Z axis totally even, no continued adjusting. You should have ordered a number of sets of all parts needed and sold them to CR-10 users at a reasonable price. Even at $35 to $45 a set, you'd be making a decent profit.

I am happy to share the details free of charge so others can make the modification to their printers if they wish.

Nice Job, aside from the actual work thanks for taking the time to make a post vid and instructions! (that in its self is a lot of work!)