Hey! This thing is still a Work in Progress. Files, instructions, and other stuff might change!

Rostock mini

by bwevans, published

Rostock mini by bwevans Oct 22, 2012


A slightly smaller, sleeker, more portable and more desktop friendly version of Johann's Rostock Delta 3D Printer. Key improvements have been made to the parametric nature of the design files with a laser cut frame generated by the SCAD file to accomodate the desired print bed dimensions. Also there's a new extruder design to go along with that will be published soon.

For more details, build notes, and other information visit the RepRap wiki at: reprap.org/wiki/Rostock_mini

More to come in the next few weeks.

Update 11.11.12: It's printing but there are still some problems with the bowden extruder I designed because of weak-sauce push-fit pneumatic fittings. Am redesigning to use a better tube setup. Once verified in the next couple of weeks I'll be posting more details and the extruder as a separate design.

Update 12.09.12: New Bowden design is complete but hasn't been working as well as it should. Still needs more testing.

Update 12.16.12: Updated v2 files for hotend_v2.stl and the still experimental extruder.stl with OpenSCAD source files in source_v2.zip. These changes get rid of the unreliable pneumatic push-fit fittings and replace with 4mm OD PTFE tubing, McMaster p/n 52335K32, and M4 nuts threaded on each end (one in the hotend and another in the extruder).

Recent Comments

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Same here. Trying to print to paper and trace to wood. What scale are the DXF's, please?

Which is the default diagonal rod length for this printer? 186 - 20 = 166mm?

Hello have you a stl file with only 1 joint because printing 12 in one time causes issues on my printer please. If you want to mail it to me: jhdscript dot gmail.com

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Rostock mini by bwevans is licensed under the GNU - GPL license.

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Start with the rostock_mini.scad source file included here to see how everything fits together and then check out the build notes over at the wiki page.


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jhd on Nov 21, 2013 said:

Hello have you a stl file with only 1 joint because printing 12 in one time causes issues on my printer please. If you want to mail it to me: jhdscript dot gmail.com

AnchorageMakerSpace on Sep 6, 2013 said:

What File did you use for the clips that hold the HPB?

michielh on Sep 7, 2013 said:

I used two bulldog clips.

HarshReality on Aug 23, 2013 said:

So.. are the plastic parts the same as those of the normal rostock or are they scaled down?

daveycrocket on Jun 1, 2013 said:

I don't understand why does it need so much torque (at lelast 4.3kg-cm nema 17's according to the reprap wiki)? Isn't the whole point of a Delta to reduce the torque needed and increase the speed?

Anonymous on Aug 2, 2013 said:

Speed can be increased in a delta design because the weight is much lower when compared to something like a prusa i2 where the whole printbed on the y or the entire x stage hanging off the z is moving. Because its fast does not mean that it doesn't need torque to move those arms. Surprised me too.

IcanCwhatUsay on Aug 1, 2013 said:

F=ma ;)

michielh on Apr 21, 2013 said:

What value in the openscad files defines the carbon fiber rod diameter/radius? What is the default for this?

michielh on Apr 26, 2013 said:

Also: How can I extract the build plates for the top & bottom frame plates to have them cut (or to make a drawing to cut them myself)

C-line on Apr 15, 2013 said:

Great work! I want to try printing (segmented) top and bottom frame pieces. How can I generate STL's of the these parts once I modify the SCAD parameters?

TaylorKnight on Mar 19, 2013 said:

is any one have a supplier for the belts ?

charlesfries on Jul 30, 2013 said:

RobotDigg.com is a great resource.

AnchorageMakerSpace on Feb 14, 2013 said:

My cnc doesn't seem to like the scale of the dxfs. When i import them into enroute the files are larger than 12 feet. Can any one grab the dimensions for me so i can scale this appropriately

Mapembert on Jan 20, 2014 said:

Same here. Trying to print to paper and trace to wood. What scale are the DXF's, please?

robo_kid22 on Feb 14, 2013 said:

Hello, I printed out the 3D parts and I am in the process of sourcing the rest of the components. I want to know the differences between the Rostock Mini and stanard Rostock 3D parts if there are any. This is going to be my first RepRap and serve as a learning experience in 3D printing. From what I can tell it appears that the mini parts are identical to the standard ones and the main differences are the lengths of the rods and dimensions of the laser cut parts. After I build the mini and have it printing I'd like to move up to the full size model and hopefully recycle as many parts as I can.

arnoldpro on Jan 28, 2013 said:

All parts are printed in black and 1 tower is build and looks very good. Thank you for this work and your great book about 3D printing. I found M3x14 better to secure the 8mm smooth rods, M3x12 seems to be a little short.

phonx on Jan 24, 2013 said:

Is the deltabot faster to printer than rerap style printer????

lordnynex on Jan 21, 2013 said:

Please don't do this.

There are some problems with this idea.
1) Supporting the weight of a spindle would make the machine 'sluggish'. sluggish being the best possible outcome.
2) There is 'play' in the arms that makes swinging a spinning endmill pretty dangerous. I imagine the spindle would effectively rip the arms off the machine.
3) With this pendulous moving weight, you would get terrible repeatability. Assuming you don't seriously hurt yourself first.
4) You probably want something made of steal. Assuming the machine slipped and didn't destroy itself, you run a very serious risk of drilling through the platform (Possibly into your electronics).
5) Any controller you get for this machine is no where near capable of powering a spindle.

If you're serious about a delta mill there are other designs for the arms that would be more suitable but this will surely break the bank. If you can afford an iModela I recommend you get one.

I assume all of the above points are futher punctuated by the fact that the stepper for the rostock extruder is not directly connected to the hot end.

lordnynex on Jan 12, 2013 said:

Stupid question: I got excited and hit print before diving into the zip files. The individual STL's you uploaded, are they the default openscad settings? Can I take the output from the echo statements for measurements?

Anonymous on Jan 12, 2013 said:

The plastic parts don't really change when the size changes. The frame will change horizontally if you move up to an 8x8 printbed for example. Vertical height is to a point irrelevant... use as long rods as you want. So yes, the STLs posted are those shown in the (in the now horribly cropped - thank Tverse) photo. Carbon fiber is sourced from McMaster - its more expensive but when you are ordering bolts anyway it makes up for it. Tower hobbies is another good place and you could pick up some ball ends there to try out.

summetj on Jan 4, 2013 said:

Awesome design, great work!

Aesthetic suggestion: I notice in the assembled picture you have three pairs of wires running down the frame from the end-stop switches at the top. But you also have six vertical rods supporting the top of the frame. Could you wire each switch directly to the two rods that support it's block and eliminate the wires going to the top that way?

arnoldpro on Jan 9, 2013 said:

I am thinking about shielding the wires to the switches, using the 6 rods will be the other extreme.

Anonymous on Dec 16, 2012 said:

Question: There is an extruder groovemount dxf file. Looking here and the Reprap wiki page, it isn't clear if that is supposed to be laser cut in cork or acrylic (there is also the part that you print). In the pictures, it looks like a black plasticy layer between your orange printed pieces. I'm assuming it is acrylic but wanted to ask. 

Anonymous on Dec 16, 2012 said:

The DXF is for cutting 5mm plywood. It slots into the groovemount of MakerGear hotends forming a sandwich with hotend.stl. It might work with acrylic but usually hotend mounts are done with wood - I think you are just seeing the burnt and blackened edges. Specifically, I use inexpensive 5.2mm sanded plywood from Home Despot. 

Anonymous on Dec 9, 2012 said:


Anonymous on Dec 16, 2012 said:

Just noticed that Lulzbot sells a similar power supply at a monster 16A(!) with an available matching plug. http://www.lulzbot.com/product...

arnoldpro on Dec 9, 2012 said:

Hi thantik,
you have to search in marlin.pde?

thantik on Dec 10, 2012 said:


Yeah, it's just not there arnoldpro... the developer is apparently merging the Marlin version for Arduino 1.0 and removed delta support from that repo.

Do you have a copy you could post somewhere of the latest version you had?  I haven't got an ETA yet on when delta support will be added back.

thantik on Dec 9, 2012 said:

Any idea what the deal is with firmware?  I've gone to the links posted in the wiki and the configuration.h in what is linked doesn't have any DELTA_ variables to set, doesn't look like it's actually for a delta bot.

Anonymous on Dec 9, 2012 said:

Just use the delta fork of Marlin: https://github.com/jcrocholl/M... The delta math is in Marlin.pde.

Anonymous on Dec 3, 2012 said:

What are you powering yours with? I don't see the power supply mentioned on http://reprap.org/wiki/Rostock.... Normal ATX?

metzench on Nov 30, 2012 said:

One thing that is not clear to me... The calculated length for the diagonal rods, is this from the middle of the jaws mounting holes or what is the needed length?

Klodd on Dec 3, 2012 said:

Hi metzench, according to the building instructions, once your configuration is correctly set in configuration.scad, when you run rostock_mini.scad, it outputs a "diagonal rod length". Substract 20mm to this and you get the required length for your carbon fibre rods, that should fit in the printed jaws.

My guess is that the length of the jaw from the attaching hole on the u-joint and the extremity of the fitted rod is 10mm. I should measure that with a ruler when home, or check the scad file.

Anonymous on Nov 29, 2012 said:

Any updates on the extruder?

rolandcube on Nov 29, 2012 said:

I found the GT2 36T on ebay ;-)  

Klodd on Dec 3, 2012 said:

I got them imported from sdp-si (I'm in France).

rolandcube on Nov 25, 2012 said:

I`m thinking to build a Rostock mini.  I'm looking for some partsDo anyone know a place in Europe where i can buy the pulley
GT2 36T pulley.

metzench on Nov 21, 2012 said:

Brian, do you use github for development? Though cooperation would be easier. I have some mods for using igus rjmp instead of lm8uu that i want to commit.

Klodd on Nov 21, 2012 said:

I just created a github repo, forked from jcrocholl/rostock.

Find all the files here :

I'll add the repo on the wiki page, I don't think it's worth creating a derivative, it should be integrated here.

Klodd on Nov 19, 2012 said:

I made some modifications to the configuration.scad and frame.scad files to allow for the use of RAMPS, adding mounting holes.

I also tweaked the file a bit so that it correctly places a classical (210*210) PCB Heatbed (as is the holes fall too close to the motors mount).

Please let me know if you would like to include those modifications.

Also, the extruder looks nice, how is the testing going ?

summetj on Jan 24, 2013 said:

I'm using a RAMPS 1.4 on mine, and would love to have this mod. Is it integrated with the current thingiverse download? (I saw the sanguinololu=false/true configuration setting but didn't see anything for RAMPS.)

metzench on Nov 21, 2012 said:

 Klodd, perhaps you might post your changes as a derivative? Though Brian can perhaps integrate that. Would be very interested to have your changes here

Anonymous on Nov 20, 2012 said:

That sounds great! Shoot me an email at bwevans at gmail and Ill get it incorporated and posted.

I just received some new ptfe tubing for the extruder so I hope to have that tested and changes posted soon.

Anonymous on Nov 20, 2012 said:

 I'd love to see these as I want to use RAMPS for this and a normal print bed.

nargos on Nov 19, 2012 said:

Hi, thanks for your work.
What are the correct settings for the firmware config.h?

thantik on Nov 13, 2012 said:

Do you happen to have a github repo that reflects your most current work?  I'm gearing up to build one of these.  My rods are 610mm tall, 210x210 build area - any suggestions?  You mentioned yours is so short to keep the frame stable, will larger build area help offset any instability and allow me this height?

Anonymous on Nov 13, 2012 said:

Only one way to find out! I think the drawback to the original Rostock is the larger size needs a larger wood frame to remain rigid and still I suspect its questionable even then. That's why Johann is moving to aluminum extrusion. In my testing so far there is a little vibration with the upper reaches of the build volume with the smaller printer. I suspect with a much higher print volume the vibration might become unusable. If you want an 8x8x15 print area you should look at the newest Kossel design. Keep in mind that all delta style printers exist at the bleeding edge of development.

ovherpt on Nov 10, 2012 said:

Working on my Rostock mini: https://vimeo.com/53214112

Anonymous on Nov 12, 2012 said:

Looks good!

abcona on Nov 9, 2012 said:

for the Laser Parts the *eps Files

abcona on Nov 7, 2012 said:

Hi Arnold,
thank you.
The owner, Stefan Canditt, from formulor.de has convert it in *,eps.
by interess i would send you the frame.eps, hotend and bed .eps ...

koutetsu12 on Nov 6, 2012 said:

 There is a nema 14 gasket file in the .zip, but I don't see a nema 17.

Anonymous on Nov 12, 2012 said:

Yep, I thought I would get away with using 14s but clearly not. I have a few more things to lazzor in the next couple of weeks so I'll be updating the gaskets then.

arnoldpro on Nov 1, 2012 said:

is it possible to fasten open belts? It is hard to get the right length in Europe.

Anonymous on Nov 5, 2012 said:

Yeah that should work. Either double it up in the belt holder on the carriage or some use a couple zip ties to attache one end of the belt to the other. This lets you tension it.

rmatrix on Oct 29, 2012 said:

Awesome version! I look forward to building your upgrade. Any ETA on the changes or additions you mentioned? Do you if anybody can source a set of printed parts. Unfortunately, I don't yet have a qorking 3D printer. Thanks for sharing your upgrade!

cla on Oct 28, 2012 said:

I am printing the parts.
I don't understand if Sanguinololu is fine to drive it

Anonymous on Oct 28, 2012 said:

Sanguinololu with an upgraded ATmega1284P will drive the printer just fine. If you have an older Sanguinololu with the 644P it will not. More details here: http://hardwired.cc/?p=256

zzarbi on Oct 23, 2012 said:

That is cool!

imberiman on Oct 23, 2012 said:

Whats your total cost on the build looking like?

Anonymous on Oct 23, 2012 said:

Honestly I have no idea! I suspect it could be built for $400-500 or thereabouts. I had a lot of this stuff laying around but I still had to drop about $200-250. Really it depends on how many corners you cut... $15 steppers instead of $20, J-head hotend instead of MakerGear, wood frame instead of acrylic, cheap Sanguinololu or Azteeg X1 with a 1284P by default instead of later replacing the 644p... all that and you might save $75-100 right there. 

Xheis on Oct 22, 2012 said:

What's the current height of the 6" x 6" build? Or if it varies, the build pictured.

I'm keenly looking forward to producing one of these.

Anonymous on Oct 22, 2012 said:

As pictured it comes in at a max vertical height of 7.5". This is configurable by setting a longer vertical rod in the config file.

jmil on Oct 22, 2012 said:

freaking awesome. nice job.