V3 vs v4 3DP build part list

It appears that the v4 is not fully documented yet. To the untrained eye, the v3 and v4 appear similar. If someone were to start a build, what would need to be considered and carefully observed to end up with a v4 and not a v3?

The largest difference (to me) is that the v3 uses a 20mm CF square tube for the X gantry and the v4 uses an MGN12H linear rail.

The v4 is mostly suited to 2020 extrusion frame buold, while the v3 is more amenable to a panel frame.

The v4 does away with the Z endstops, and the endstops that it does use are the simple switches instead of the optical ones.

Both use three independent Z motors, are CoreXY based designs, and are designed to use a BLTouch Z probe.

The v4 isn’t fully documented. I am just finishing mine up personally though so it’s definitely possible to do


I’ve been reading your build log. You got your build list off of the fusion drawings?
could you post what parts are specifically different besides the panels you put on?

I have another question, but it is either super obvious or will showcase my lack of 3d printing understanding. A little background first: I have an ender3 recently upgraded extruder and bowden tube, custom fan with octopi running custom marlin 1.9 becauese 2.x won’t fit on the board memory. It now prints amazing compared to when I got it at 60 mm/s. I would say my 3d printer skills are mid-level beginner, perhaps intermediate. It is a tool, not a passion for me and my question isn’t meant to be rude or disrespectful so here goes:

Why would I build an MP3DP instead of buying a $200 unit off Amazon? What would be the equivalent price for a similar capability of the MP3DP with the same quality of parts?

My specific questions are more along the lines of should I go 300 mm or 250 mm. the 210 mm I have is a little small, so a 300 might be nice.

I have an MPCNC I built last year, but literally no space to keep it. I had to take it down for winter to get the car in the garage. I really want to build a lowrider, but I have zero space for that, so I could build an MP3DP with the parts, but I don’t know what I would get after all the time and $ for parts that I couldn’t just buy.
My parts list so far includes:

  • bed
  • corner aluminum and T attachments
  • extruder
  • linear rails
  • hot end

You may ask why I need to build when I have one already? My printer is going for a sabbatical to my son’s house soon and so I have one of three options:

  1. get a new one
  2. build a new one by repurposing the mpcnc electronics and steppers with some 20/20 sitting on a shelf
  3. mooching off a few nearby friends who are always willing to print stuff. Seems like there are now a lot of people with 3d printers wondering what to print…

I like #2, but if #2 costs more than #1 for just enough parts to finish, then that leads back to the question posed above… until this is sorted out, I’ll go with #3. Thanks for any further input.

Apples and oranges.

The $200 Amazon special will probably work. Well, what you have works. This is for “works better.”

There’s nothing really wrong with most of these printers, and there is certainly a diminishing returns element. It costs a lot more to get a little better generally.

My Repeat compares well to some failrly high end stuff. I haven’t the really expensive printers, but I’ve seen them at work.

Some of the advantages to the MP3DP v3 or v4:

True bed levelling. This is ONLY available with independent Z motor control, and requires 3 channels. Two motor bed levelling also exists, and is actually pretty good though.

CoreXY motion. This has less moving mass than most Cartesian designs where one motor exclusively deals with each of the X and Y axes. This allows faster printing with fewer artifacts appearing in the resulting print. Less printing time also reduces the probability of other problems like warping or clogging nozzles.

This is harder to answer. Apples to oranges again, I guess.

In similar configurations, you could look at a Railcore (Google says $1700 USD) or a Voron ($1350 USD) with options that can bring those over $2000 easily. Are those similar quality? My printing results versus what I see people who have those would say it’s in a similar class, but there are thinks to take into account. Can I get that result at the same speed they can? I don’t know.

Or you can look at a genuine Prusa MK3S+ for $1100. This is the same general configuration as your Ender 3, and while you can probably get the same performance from yours, chances are, you won’t.

With the MP3DP the quality of components is up to you. I have an E3D Hemera extruder for both my v3 and v4. That’s a pretty good unit, at a cost approaching the whole cheap Amazon printer kit, but I’ve used many cheap extruders, and this is worth it to me. My self designed printer uses E3D V6 clone parts, and gets satisfactory performance, but at a loss of Z height relative to the Hemera, and is much more picky to load filament into. Probably a difference of about $60 or so. My printer was designed around this, so I couldn’t change to the Hemera on it. On the Repeat, it would cost me about 40mm of Z height to use the clone parts.

Since this is not a kit, you will end up paying more for parts than the exact same ones that did come in a kit, but you pick and choose the parts.

I very much like having a 300mm print bed. This basically requires increasing the rail lengths.for X and Y by 100mm from the base Fusion360 model. That said, it is very rare that I actually use all of that real estate, and I am still using power to heat it all. This is one reason why my V4 is smaller. (I actually wanted to build it for 200mm.)

You will probably spend more for this than if you picked up, say a CR10 kit. (Just looked it up and for $390 CAD I can get a CR10 kit (300x300x400mm build volume) which is about the cost of my extruder and control board.)

It’s not like I couldn’t make the CR10 work. If I just wanted a functional 3D printer, that is a pretty good deal.

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The MP3DP is really a side project for Ryan. He uses them in his print farm to build his products (low rider and MPCNC). He shares the files with his friends (us, on the forum) and anyone else that wants to use it.

There will not be instructions like there are for the MPCNC. Anyone who wants to build it needs to find motivation themselves. It isn’t evident to beginners, or people who have a different approach to printing.

If you are looking around at the many extruded corexy printers, you can compare this project and probably see where it fits in. It isn’t even a kit. Everything is customizable. So the quality and price of parts is up to you. The final output is dependent on you, how much you can learn, and how hard you try.

This kind of question is leading toward some kind of flexing about the best bang for the buck and this project is just way too chill for that.

Ryan uses them in his print farm and he runs a business. Time is money in his garage. That is the only endorsement you will get. But take it with a grain of salt, because Ryan knows the feel of a properly tensioned belt and how much out of square is worth fixing. He also gets some value from doing the project that he wouldn’t if he had a farm of prusa or bamboos.

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Thanks to both of you for your answers.

I’m kind of put off by that comment, but probably misinterpreting it. The goal in asking these questions is to understand the investment side of this vs the canned options to justify in my mind what is to be gained from making it (sweat equity and experience and final part quality) vs buying it and where kit sellers cheap out on stuff and why building your own seems a desirable thing to do for more folks that just Ryan. If it really is just about being able to beat my chest to say I did it, well then normally I’m in, but typically there is a cost benefit to sweat equity vs outsource pricing. If there is a real advantage in terms of size / cost / quality of print / functionality / availability / reliability / print speed, then that is what I’m seeking to discover or is this a trophy I earn by building and is itself its own reward. The gift that keeps on giving as long as you feed it filament…

MPCNC is showcased as a sub $500 build after you have your own table. What would be the tag line for the MP3DP? If one could state that the MP3DP for a 300mm bed is “on the order of $x with excellent customizability for a full user-led design and build experience,” that is ok too. I’m just trying to sort out what that value add is for me to justify the journey.

In 3D printing, I don’t know the full story to make those calls, which is why I’m asking. Which parts do the kit sellers cheapen that have to be upgraded to be of the same caliber as one that is fully custom?

@SupraGuy, what are you into yours now in parts if you don’t mind my asking?

I think my parts list is as follows:
complete mpcnc kit pulleys, idlers, belts, endstops, etc (have)
skr pro 1.2 with 5 drivers (have)
raspberry pi (have)
5 steppers (have)
1 TMR 2206 (6th) driver ($10)
1 stepper ($11)
12 V power supply (have)
24 V power supply 6.5 A ($27 recommended?)
20/20 extrusions (have - need to measure/cut)
corner plates ($20)
angle brackets (have)
t-nuts and screws (have)
Side panels (have)
linear rails (?)
hot end - sensor, heater block, nozzle, etc. (?)
Bed holder (?)
Bed heater (?)
Bed (?)
Printed parts
mood lighting
padded feet
other stuff I forgot?

I’m interested in recommended brands for the ? items.

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I’m sorry. It was a risk when I said it. I think that is a fair question for something like a bamboo or a seckit or a voron.

The tagline would be, “build this is you’re curious”. It is not a product like the MPCNC. It is a side project.


I don’t mind asking, but it’s pretty hard to total up.

Things I bought specifically for thus build: (Canadian dollars, give or take $0.75 US)

  • 2020 extrusion, tee nuts, slide nuts, corner braces etc… $200
  • Duet 3 6HC motherboard $200 ish
  • 24V heated build plate, magnetic sheet and removable plate $125
  • BLTouch clone probe $35
  • Hemera extruder/Hot end $140

Other than that, an order from the V1 shop for 5 motors, bed springs, end stops, pulleys and idlers… I don’t remember how much…

Plus about a half spool of filament, about a half sheet of 1/4" plywood, a bunch of screws and nuts…

I’d guess I’m about $1000 deep in the v4, counting stuff that I just always have on hand for projects. I guess that’s about $750 USD. Not as bad as I thought, but more than I’d spend on a kit.

Keep in mind here that I do not need another 3D printer! I built this not to have another printer but because I do it as a hobby. If I get something that could hang with a Railcore that would cost me twice as much, that’s awesome, but I think the Railcore is probably more capable, but I could almost certainly out-print one if I built 2 of these. The downside being that I would need to have a place for 2 of them. How often do I need to have more than one printer going? Well, in the time since I built my v3, I have used both it.and my old printer concurrently in 2 occasions. Once building the LR3 beta and once building the v4.


I can tell you right now the Railcore kits from Filastruder(currently the only kit seller) has very little skimp. Their kit is actually more expensive than the kit I bought when it first came out from Project R3d. Better components, less printed parts. Which is why the kit is expensive.


Thanks for fielding my questions anyway. I realize it isn’t fair to put chinesium commodity builds against quality builds with high end parts and expect the ferrari to compete with the hyundai on price. I am looking for bang for the buck, which is what you were getting at. No need to be sorry. You had the right idea. If there was a chance I could get a $400 printer quality for a couple hundred dollars and some time given that I already have a fair bit of the parts, it would be very attractive and justifiable.

Thanks @supraguy for sharing your cost estimate. That is very helpful. The v4 is a high end product that rivals $2000 machines (@barry99705 thanks for the name to search. that was an interesting read) and can be sweat equity built for $750-$1000. That is either a labor of love or a hobby build for performance. That is a good value, but is in a different tier than I require.

In trying to see if building one of these is really a good idea for me or not, it sounds like it isn’t at the moment based on the cost and on the time, but mostly the time. At times I need/want printed parts, but for me it doesn’t make sense to drop $1k on a printer I’ll use a few times a year when one about 1/5th that cost will work and it can be purchase partially built. It won’t be as sleek or sexy, but maybe some V1 stickers will spruce it up.

Thanks again for the responses. This has been educational.

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I know this is a bit old, but maybe I should jump in a little bit.

I am not really sure where this fits into the V1 ecosphere other than when people see it in the background of a picture they would ask for files if I didn’t release it. I do make them to suit my needs as a print farm, I enjoy designing and building them, I learn a ton, and that learning gets passed on to the CNC’s. There aren’t many instructions because I just came off the Repeat build and it failed my longevity tests, so I made a quick V4. It is holding up so I am just finalizing 4.1 (prettier parts, some minor modifications). These new parts are in the CAD but do for a proper release as soon as I test out the CNC’d walls. There will be more instructions but never to the extent of the CNC’s. I have no desire to be a 3D printer company.

In the end I would pitch this as a CNC project, I always have. The people around here tend to have a bunch of leftover parts and CNC machines so I think a handful just build one to put that stuff to use…and most of us like building things.

As for the speed printers I would love to see how they hold up to 24/7 printing. Can this new printer of mine print super fast…heck yes…do I print super fast with it…heck no. I need these to last, and print very accurately. I think you will notice there are lots of “slow” prusa print farms, and no hevort farms that I know of. Speed takes a toll. So these are right in between in terms of performance, but on the low end of both in cost.


Appreciate the info about how you view things, and the heads up on what to expect. My transparent Red PETG is here waiting to make a V4.1…

Curious what you think of putting CNC’d panels on the inside of the frame? Linear rails would be fastened through/to the panels in this case? Goal being so wiring can be attached to the inner wall. Optional Exterior wall panels could then encapsulate insulation, reducing thermal-loss/noise, heating/energy cost? I haven’t looked closely enough at Repeat V2 yet, there’s probably stuff in the way that’d prevent this. Will take a look after I wrap up scratching acrylic.

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The CAD for the 4.1 is done, except what I want to do with the LCD. So the link for the CAD will let you pull the STL/3MF right now and you can start printing. Until I mess with it a bit more I would not cut the plates.

I did actually kinda look at this. Here is my suggestion. Keep the outer layer, if you want to add more make them fit in the extrusion grooves that will give you at least 10mm for stuffing. I considered just making the plates to slide into the groves but I wanted to ditch the expensive and fugly corner brackets as well.

Why did you guys go away from the wood frame? Just ease of assy?

Ease of adjustment. We’ll see how the panels over extrusion works out.

I am getting pretty picky with my printing tolerances, I really really like to be able to print square cubes.


@vicious1 thanks for the perspective. My interest in the MP3DP “line” of printers is very recent and the history and background of it helps. Making 3d printers makes your business work better. That makes sense, but it isn’t really a product line of your business on purpose, it is more of an effect of doing your business well. I looked at the web page and figured it was just one of the products offered that you were actively developing and marketing with version upgrades as you rotated through the mostly printed lineup… and it kind of is, but it is a byproduct, not the bread and butter.

By the way, the new web page looks great!

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Thanks, still messing with it daily. Been working backwards to add all the old blog posts, probably have about 20 left to go. I have to change some links and find the old pictures for them. It takes forever, but boy is it a walk down memory lane.

It is just really hard to make a truly “make it yours” 3D printer. It is very easy to make a printer and say this works. Around here, I make a printer and everyone uses a different board, firmware, extruder, bedtype power type, and size. Each iteration I am trying to make the parameters easier and easier to adjust but Fusion does not seem to be good at that, so I have to learn to work around the issues there, but that takes time. (speaking of…I have learned a few things there).

If you did happen to change your mind, making it exactly as I do will save a lot of work on your end and will go together just like our CNC’s. Changing anything means you will need to put in some work in one way or another.

My son is taking my ender today… guess I’ll borrow one and reprap it into a v4 so my primo parts aren’t languishing in the box begging for use. It may take a while though. I’d say buckle up, but it will be more like the harbor cruise…

Cool. If you start printing, remember to take the new files from the CAD link directly, not the files on printables. I have had tons of emails this morning so far and my plate is filling up fast, adding new STL’s are on my todo list but it just keeps getting pushed back by other things.

Never used fusion360 before. Looks like the STLS can just be exported. Is there a recommended print orientation for each part?

If I measured correctly, it looks the following are needed:

8 ea 345 mm 2020 extrusion (or 350?)
3 ea 370 mm 2020 extrusion
3 ea 305 mm 2020 extrusion (or is this 300?)
1 ea 300 mm MGN12H rail
5 ea 250 mm MGN12H rail

is print size as drawn about 240x 240 x 250? or 210 x 210 x250 (and may depend on the exact exteruder chosen)? My mouse clicks may not have been as precise as they should be. Does this look right?