PrntQB V2

by AndyCart Jun 20, 2014
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Looks great! I didn't see the power supply switch mount in your files and its exactly what I am looking to add to my Corexy. Is that yours or another THING?

is the PrntQB V2 still supported? I've been thinking of building this or a D bot.... are you still using yours? Thanks!

What are the dimensions of the printer?

Permission for profit uses?

Maybe i'm missing it, but what is the build volume on this printer?

well i was not paying attention to the build parts and found that all parts printed properly. I am almost finished with my build and will post soon

I have tried to print the parts and I am having a size issue. I am using S3D to slice and print however i am not getting the right size. the Y-carrage is too small, i am trying to find the correct scale, that will have it in proper proportion. the Y-rod brakes are printing with a 8mm Mount hole instead of a 10mm. please help

I want to use drop in t-nuts anywhere things mount to the aluminum rails. Anyone know which nuts in the BOM I would be replacing? I am guessing it must be either the 30 x M5 half nuts or 42 x M3 nuts. Seems like maybe the M5 half nuts are maybe to be thin enough to fit down the rail and they are paired with 10mm bolts which seem like the right length but anyone that might know I would appreciate it.

Hi i am gonna start building a corexy (just ordered electronics) and i like the simplicity of your design and i like how you keep updating your design. But i have to have to ask if you have a V3 around the corner with belt drive instead of fishingline or some other update?

My PrntQB v1 uses belts

Hi Andy can you help me again?
I don't know how to configure the z axes so that it moves by G1 Z0.200 F4800 0.2 mm down. My Printer goes 9.8mm down (z is only 10.0 mm)
I have try something but I don't get it.
Please help me.

It's probably your steps/mm in Marlin that is incorrect. If you have used M8 threaded rod and 200 (1.8 degree) step stepper motors with 1/16 micro stepping (all three jumpers on under the A4988 driver boards) then the value is 2560. F4800 is way too fast for the Z axis. Try 4mm/s (#define HOMING_FEEDRATE {5060, 5060, 4*60, 0})

define DEFAULT_AXIS_STEPS_PER_UNIT {55.94,55.94,2560,640}

Does your BOM include all of the parts for the Greg's Wade Reloaded extruder? I see the compression springs but I don't see a hobbed bolt listed and most of the kits I have seen also include some m4 bolts but I don't see those listed either.

I may have missed them. It's just a normal Greg's Wade extruder I use an M8 50mm bolt with the hobbing 25mm below the bolt head underside. You will need 3 x 608 bearings a small, 19mm length of M8 rod, 2 x M3 50mm bolts, 1 x 30mm M3 bolt, a 1/8 BSP threaded pneumatic connector, 3 x M3 8mm bolts and 3 x M3 nuts

Great, thanks for the update! This is my first build so I'm afraid I will miss some things that are just common sense for more experienced reprap builders.

Simple designe with less printed parts and great design. I would like to make some changes. Could you please
share the source files if possible. That will be great


Hi Andy,

I'm nearly finish with my printer but I have one really big Problem. My fishing line always goes between the bearings and I'm not really sure if I have wired it right. I have wired it so:
X-carrier --> Y-Carrier_L --> Motor_L --> front corner_L --> front corner_R --> Y-Carrier_R --> X-carrier_R
And the other one:
X-carrier --> Y-Carrier_R --> Motor_R --> front corner_R --> front corner_L --> Y-Carrier_L --> X-carrier_L

Can you help me?

Hello! Cool design! Is there some detail instruction or build log of 3d printer like this? I am beginner, but want to build my own 3d printer. Thank you!

I've built a couple repraps but never a corexy could you explain the firmware/settings/host software you used?

I used standard Erik Zalm Marlin and I use Repetier Host and Cura.

//=============================Mechanical Settings===========================

// Uncomment the following line to enable CoreXY kinematics

define COREXY


I am getting close to having all the parts needed to build my own PrntQB v2. I am planning to use a glass print bed with the intention of being able to add a heater so I can print ABS and other materials in the future.

Anyway, I noticed that you have been using this carbon fibre vinyl on your print surface. I am not familiar with it. Is it a special vinyl film? Can you provide more information or perhaps a link to a supplier. I just want to make sure I buy the right thing.

Thanks again,


Hi Brent

I use this http://www.ebay.co.uk/itm/3D-Sticky-Back-Carbon-Fibre-Sticker-Vinyl-Wrap-Film-Bubble-Free-Lots-of-Size-/190716224670?pt=LH_DefaultDomain_3&var=&hash=item2c6792a49e but I haven't tried it on a glass bed. It works great on an acrylic bed but then again so does kapton tape.


Can you confirm the printed part counts. It looks to me like I only need one of each item except for the following:
Bearing_Bracket: 2
Filament_Drive_Spool: 2
Y_Carriage: 2
Y_Rod_Bracket: 4


Hey Andy,
any chance to get the source files? I would like to adapt it to use a cheap square aluminium tube and to use 8mm rods only.
I would never publish them anywhere and use only to build a machine of my own.


Hi Andy,

it's me again I hope I can ask you one mor Question?
Can I also use this Hotend?

I think I can Build also one Printer in the next weeks. I have nearly all pieces there without the Hotend and the printed parts( I search after someone how can print they for me)


Hi. I don't see why not. It looks the same size as a J head

Hi Paul

4 10mm Igus bearings in the Z carriage running on two 10mm steel tubes. Build platform bolted on springs to the two angles attached to the carriage to allow for levelling. Pretty straightforward really. I sold the machine so I can't take any more pictures. The video shows it all pretty clearly.


Hi Andy,

I can't see how you z axis is mounted have you something special?
Can you make more pics (backside is really unknown)? I have ordered some parts and want to begin my printer asap.



I'm ether blind or not enough coffee this morning, but how is the frame held together. I can see brackets in any of the corners. IThe one made by a user and pictured shows corner brackets, but I don't see any on your and no visible means of support :) I know it has to be there some where but just dont see it or any stl files named like thats their job :)

It's all held with M6 dome head screws. The four vertical extrusions have a 5mm hole drilled through the centre 'square' that forms the base of each T slot, 10mm from the end and on each side i.e two holes in each end at right angles. The ends of the horizontal extrusions have the hole in the centre of the 'square' tapped to M6. If you screw the dome head into this hole with just enough clearance to slide into the T slot on the vertical extrusion you can use the 5mm hole to insert the allen wrench to nip the dome head up to lock it all together. Not my idea. I found it here :-


This is a great idea.

Unfortunately the referenced blog is private so the link isn't too helpful. :(

It wasn't when I grabbed the idea from there :-)

Hi Andy,

Is there a significant difference in print quality / speed between this printer and you previous design with timing belts?


Hi Paul

The belted version runs quicker but not by much. I run the filament drive verson at about 60mm/s the belted by about 80mm/s. The end result in terms of time to print an object is fairly negligible. Less than ten minutes on an hour long print. It's got more to do with the 'freeness' of the carriages than anything else. The belted version uses conventional linear bearings on precision ground rod. This also makes it quite a bit more expensive though, especially when you throw in the belts and pinions.


@AndyCart did you have trouble with the bushing holes on the Y-Axis being over-sized? It seems that horizontal holes like that tend to be weird because of bridging at the top. I had binding issues that I fixed by shimming around the bushings. (granted my parts are actually redesigned equivalents, so maybe you did something special with those holes that I didn't notice.)

No I didn't have any issues. In fact mine were a tad tight. I had to run a roll of emery paper through them a couple of times to get the bush to fit.

You sized them right at 10mm (for the 8mm bushings)?


I have no printer but I want to built this one. Is there anybody how can print me the plasticparts?

And have anybody a link tu the J-Head I'm not sure witch one I must buy.

I used this one http://www.aliexpress.com/item/J-Head-Hot-RepRap-3D-Printer-MK4-MKIV-J-Head-Hot-End-0-4mm-nozzle-1/1716255822.html but you need to dis-assemble it and fit a short piece of 4mm ID tube (about 3mm) between the pneumatic fitting and the PTFE tube inside to stop the PTFE tube moving in the PEEK housing. After that simple mod it's an excellent hot end. I use them on my Cherry Pi range.

Comments deleted.

Just finished up a build on one with carbon fiber rods and IGUS bearings. Do you have any tips on getting the Spectra line tight? I'll post a picture under "Made" when done.

Did you wind up with the washer between the bearings that the line rode on? It looks like there is just one between the two sets of bearings on the outside posts, but I can't quite tell about the sets in the Y-carriage. It looks like "washer, bearing, washer, bearing, washer", but the line goes into the space where the washer is. I was thinking of trying "washer, washer, bearing, bearing, washer".

I also have a delta with some of your Cherry Pi parts and am about to put the line on it, but on that there is room, under the carriage, to put a something to take up a bit of slack. On my Kossel the belt is connected with a pull-tie and that was just pulled tight. I believe the current delta with the 2020 extrusions will be slightly more stable than the Kossel with 1515 extrusions. I like the Kossel a lot and the belts are fine, but thought the Spectra would be a bit less costly, especially on the CoreXY. Switching the delta over to gt2 would not be so costly, just three gears and the belt.

I used 4 self tapping screws (No. 4) with pan heads. Wrap the line once around the head as it comes through the corresponding hole in the X carriage and pull it tight. While holding tension on the line wrap it round a couple more times then nip the screw up. It's a three pairs of hands thing!!!

No washers between the bearings. On the Y carriage pairs its. washer, washer, bearing, bearing,washer. You need to nip the M3 screws up tight too, to stop the line working it's way between the bearings. On the idler mounts it's washer, bearing, bearing,washer, bearing, bearing, washer and nip those tight too on the M5s.

Spectra line should work well on the delta. I built a 3DR a while ago and it was fine.

I'm looking forward to seeing some pictures. How did the Igus bearings work out on the carbon rods?

How rigid is the build platform? It seems like it is kind of a lot of cantilever being anchored only on one side. I think this design would work nicely with a larger print area and I'm wondering what you think about adding guide rails on the opposite side of the build platform and another set of rods at the bottom of the Y-carriage to help with stability / stiffness?

It's not bad for a cantilever design. There is some platform shake at high (80mm/s +) speeds but it doesn't seem to affect print quality. Stabilisation at the other side of the bed wouldn't hurt.

Can you provide the source files for this? I'm building a very similar design but using OpenBeam extrusions. (I had them...)

I use Sketchup to design with. I can't issue my source files complete but you shouldn't need them. I'm assuming you have 1515 openbeam. If you have 2020 you definitely won't need them. The only files you need to modify are the idler mounts and the motor mounts, possibly the rod end mounts too. PM me and I can send you those. Alternatively you can download the Cleanup plugin for Sketchup, load the .stl, run Cleanup and it will basically put them back to source.

Hi Andy, I was wondering if you ever considered adapting your cherry pi t-slot carriages for linear motion with your this and your corexy designs? Did you not like the steel bearings riding on aluminum? I'm developing a similar Corexy printer, but want to use the t slot for my linear motion. Thanks for the info.

Funnily enough ... ????
I'm actually working on this now. The beauty of core xy is that all belts/filaments are always in tension this relieves the carriage mechanisms from a lot of pressure so they can be fairly light weight and minimal. I'm trying to design this sort of simplicity into my V3 design. The ability to use the power transmission system as a structural item is key.

Could you, please, provide the configuration file, and eventually all the modifications you did to the firmware? Did you use Marlin or Repetier?

a more compact version with everything within the frame...http://http://www.thingiverse.com/thing:380595www.thingiverse.com/thing:3805...

Build-plate Flashlight Bracket (MakerBot)
by dragosr

I'm currently on vacation so won't be able to post any images, etc for a couple of weeks. The Spectra line path is fairly simple. Start by threading one end of a, roughly, 2M length of 100lb Spectra line through the aperture in the RH Y carriage that's closest to the stepper motor. Thread it through the RH front hole in the X carriage and tie it off on the self tapping screw directly under the hole on the LH side of the X carriage. Clamp the X and Y carriages so the print head is pretty much in the centre of the print bed. Next pull the free end of the line tight and bring it around the LH side of the RH stepper motor line spool. Wrap the line about 6 or 7 times around the spool. Make sure the line that you secured to the X carriage enters the spool at the bottom and exits at the top on the opposite side. Take that line and run it around the bottom pair of bearings on the rear RH side of the printer and then on to the top set of bearings on the LH side of the printer. Thread the line through the rearmost aperture in the LH Y carriage, through the rear hole in the X carriage and tie it off on the self tapping screw under that hole. Make sure the line is tight, I.e sounds a note when you pluck it, and that it runs in the groove created by the three pairs of bearings. Do exactly the same for the other line from the other stepper motor. It's a standard core xy path with the necessary cross of lines occurring on the side of the machine opposite the two steppers between the 4 pairs of 16mm bearings. There's a great diagram here. http://corexy.com/theory.htmlhttp://corexy.com/theory.html

Good morning Andy, could you show pictures in the path of the line so the y-axis as the x? I like your printer and see if I want one of this, I have the fishing line here, thanks.

Any chance on getting a quantity of all the printed parts, like how many of each to print?

It's really as per the video. One of everything apart from the Y carriage (2) and bearing block (2)

hi, great job .. I was contemplating on converting my printrbot jr to something better and this is perfect .. but in all corexy configs i am not a big fan of the motors and pulleys hanging out of the frame.... If everything is moved inside the frame does it reduce the printable area a lot? also why didnt you use a cable drive on z axis like the tantillus?

I love the idea of being able to enclose the printer i can sacrifice the build volume since it won't be much more in cost to extend the frame. And in that case i can have better control of temperature.

That was my pupose also ,,, i dont like things sticking out of the frame .. putting everything inside keeps things neat, and safe from accidental damage and as a bonus you could make a heated chamber...

I never thought about putting things inside the frame. I'm sure it could be done but I would reduce the print area. I guess you could increase the frame size but then it may flex. Try it and see! I've never seen a Tantillus. I like the simplicity of the 8mm threaded rod as with motors off it holds the platform

For some reason Thingiverse is refusing to display a couple of .stl for the extruder body and the large gear. I will try an upload them again on my return home

I have updated the Instructions with a BOM. I'm on vacation at the moment and working from memory on my iPad. My memory is not what it was :-) and accessing Thingiverse from my iPad is challenging as it keeps bombing my browser out. Apologies if I've missed anything

Great design! Looking forward to see more of it documented!

Nice build! Can't wait to see the BOM and maybe the source of parts to achieve the budget.

A series of pictures would be nice.

As soon as I'm back at home I will take and post some detail images. It's fairly self explanatory once you have the parts printed what goes where

Looks great, what bearings are you useing and if not lm8uu can you adjust for them.
Could add this to my to do list...

The bearing on all carriages are plastic ones from Igus. Just basic tubes with flanges. 8mm ID 10mm OD on the X and Y and 10mm ID 12mm OD on Z. 4 on the X carriage, 2 on each Y carriage and 4 on the Z. I got them as free samples from Igus. Just go on their website and order the samples. The bearings for the Spectra line are 16x5x5 on the frame corners, 4 on each corner with a washer to seperate the two pairs to form the 'groove' for the line. The Y carriages each have two pairs of 10x3x4 bearings. Just normal bearings. You could adjust the .stl files to take LM8UU but that would mean using proper ground rods for the rails which defeated the object I.e £100.00 for the build. My PrntQB V1 uses this format.

Can you give us the product id of the Igus products, i have tried to find them but i'm having a hard time of it. Thanks!

The Igus iglidur part numbers are on the BOM I've just posted under the instructions tab. I got mine from them as free samples but they are fairly inexpensive

Looks terrific; congratulations!
Are you planning to publish a BOM and/or build instructions?
I'm particularly interested in your spectra-drive system. It looks like the line runs in grooved ball-bearings...where did these come from?

See above re bearings. I will sort a BOM out at some point. Keep checking back