Anyone with experience building a 3 foot machine?

[DBFIU]

I am about to pull the trigger on building a large machine, I need to know if anyone has experience with any caveats (the physics) of a machine this size. Is droop a problem due to the span of the rails? How about vibrations or resonance due to size? I am looking at it from the perspective of size, all else being equal (same belts, rods, etc...) I need to know if there is anything you encountered building a large machine that is important to know.

Thanks!!

[JohnA136]

Go to some of the popular RepRap forums and look for a guy named "Jetguy", he is the master of building huge RepRap printers. We had him in the booth next to ours at Maker Faire in New York and his mega printer was awesome. He can answer your questions about harmonics, resonance and vibrations.

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[Geoff]

Did you by any chance see what sort of stepper motors he was using on that John? from the photo they almost look like nema17's

[JohnA136]

They looked like NEMA 17s but they were about four times bigger!

[Geoff]

They looked like NEMA 17s but they were about four times bigger!

Thanks, that does actually give me a start!

I literally throw HUNDREDS of steppers every week, often they are $200 each and made in japan, but once a photocopier is end of life, they get trashed and we often just don't have the time to pilfer them, but I am starting to mass a really good collection of extremely high torque 12v and 24v steppers - some of them are $500 ea..