# Specific 3D Printers, Scanners, & Hardware > RepRap Format Printer Forum >  Wilson 2

## JohnA136

Has anyone on here Printed/Assembled a Wilson 2?  Any hints or known issues we should be concerned with? TIA
printer.jpg

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## JohnA136

I guess nobody is interested in a large format RepRap printer.  We finished printing all the parts and started the assembly.  So far, so good.

IMG_0874.jpg

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## JohnA136

Printer is complete.  Will calibrate and test print this week.  Assembly looks beefy and stable.  

IMG_7861.jpg

No idea why my pics are not orienting correctly when I upload them? Even tried rotating to no avail?

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## Roxy

That looks very nice!

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## JohnA136

Thanks Roxy, my son wanted something new to take to the Midwest RepRap conference  :Cool:

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## JohnA136

Here is the first print on the Wilson.

print1.jpg

Just learned that Joe Prusa is flying out for the Midwest RepRap Conference in March.

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## JohnA136

Well, we had to re-do the belt idler bearings to smooth out the prints, much better results now.  I'll call this printer ready to put in the line now!


IMG_0984.jpg

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## Geoff

Nice! I am interested in a large scale one! as soon as I get my normal scale one working properly..

I changed the extruder to a geared extruder - it works really well, but I'm having trouble calculating or knowing how to calculate the new steps per axis. Nothing else on the machine changed, so it's wierd.. The extrusion is perfect, it's not the extruder steps, it's the Z steps.

My print starts off really well - the first layer is perfect, but instead of it raising the Z axis by 0.2mm increments to print each layer, it does the base layer perfect, then the next one at like 0.4mm high, then the next one at 0.8mm high etc.. 
It's way out of whack :/ 

Oh well, gonna be one of those Sundays!

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## JohnA136

Sounds like something might be wired wrong, double check everything first.  One time I had one jumper off under the stepper driver card and it drove me crazy until we found it.

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## Geoff

> Sounds like something might be wired wrong, double check everything first.  One time I had one jumper off under the stepper driver card and it drove me crazy until we found it.


Ironically haven't changed any wiring after it was working fine, just the firmware is a completely new one so it's still getting setup. The prusa calculator and all the other things just confuse the hell out of me..

I think I might have it, I think the steps per unit for Z were stupidly off.. Everything official is telling me 4000, the calculator telling me 2560, but all the forums saying 394...

Seems like 394 did the trick lol or close too it, just fine tuning now. 

I often forget that there is a tonne of controls in the LCD panel, I barely even look at it because Im punching in commands to pronterface... But yeah I adjusted the E steps and the Z steps and she is printing again... This prusa has been the only pain the ass printer i've built. I swear im sticking to kossels if I can't get this sorte haha.. they are so easy to calibrate compared to this, or at least to the point where the prints are A1.

Anyone who is ever on Ebay and sees those $390 clear acrylic prusa printers.. and you think to yourself.. hmm maybe.. could it be any good for $390?? 1.75mm, 0.4mm nozzle, 20x20x20....

Well, a year later and it's cost alot more than that. A new extruder (didn't skimp, got a merlin Hexagonal) (as they sent 3mm with the kit!! ) their hotend assembly was so cheap it broke in 5 minutes of printing, printed a new geared extruder... bought new hobbed gears, new steppers etc.. 

Never by anything with "Sintron" or "Aurora" in the title.

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## Roxy

> Never by anything with "Sintron" or "Aurora" in the title.


Or Geeetech....

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## JohnA136

Glad you got it figured out!  We have several Kossels and several Prusa's. Not really sure which one is easier to configure.  This new Wilson 2 is really like a Prusa on Steroids!  We plan on using it to test out new filaments, like Nylon, Wood and Metals.  It has an all metal extruder so it can run much hotter.

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## Geoff

> Glad you got it figured out!  We have several Kossels and several Prusa's. Not really sure which one is easier to configure.  This new Wilson 2 is really like a Prusa on Steroids!  We plan on using it to test out new filaments, like Nylon, Wood and Metals.  It has an all metal extruder so it can run much hotter.


I'm keen to see it in action!

I have this thing printing well now, but the scale is off lol.. first time ever in my printing history have I had a scale issue.

Printed a 40mm cube, came out at 31mm all sides (printed flawlessly. dead straight..) just a tad small...

Is this a marlin thing? I've checked belts and everything- the prints look very very good, it's purely a scale issue which I can get around by scaling up sure, but it's alot of second guessing.

Roxy.. you're the Marlin expert, any ideas?  :Smile:

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## JohnA136

I think scaling is in some setting, not in the mechanics of the machine. There has to be a setting where one revolution of your axis gives (x) amount of movement. I know when we changed the lead screws on one of our machines from threaded rods to acme rods we had to change something.  I am sure Roxy knows the answer.

This is a picture from four hours into a seven hour print from last night. Trying to get some sample prints to bring to the Midwest RepRap Conference in a couple of weeks.

FullSizeRender (8).jpg

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## Roxy

> Printed a 40mm cube, came out at 31mm all sides (printed flawlessly. dead straight..) just a tad small...
> 
> Is this a marlin thing? I've checked belts and everything- the prints look very very good, it's purely a scale issue which I can get around by scaling up sure, but it's alot of second guessing.
> 
> Roxy.. you're the Marlin expert, any ideas?


No...  This isn't a Marlin thing.  Some how, some way, you have the wrong number of stepper pulses per unit of travel defined.

You get to control exactly how many stepper motor clicks constitutes 1mm of travel.   You would just scale that number up by 40/31 (x1.29).   Play with these numbers to get your Cube at 40mm.

#define DEFAULT_AXIS_STEPS_PER_UNIT   {80, 80, 80, 93}   //These numbers are for my machine.  Scale your numbers on this line to get to 40mm.

It might  be good to turn off your EEPROM settings until you have this dialed in.  You don't want any bad numbers coming out of the EEPROM and being used.

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