Another thing about motors:

The first motor you speced has an Amp rating of 1.7Amps. Without proper cooling, the A4988 drivers will not handle that well. The second motor is 2 Amps. That is the maximum rating for the DRV8825 drivers. We wont even bother talking about the 3Amp motor.

You should also know that when dealing with motors, speed can become a concern too. Higher-torque motors are often slower. You can determine their speed using this calculator:

http://www.daycounter.com/Calculators/S … ator.phtml

The speed rating isbased upon voltage, amperage, and the inductance of the motor. As long as the calculator shows the motor is capabe of at least 1 revolution/second, you should be fine (most motors rated under 2 amps are good). If it is not (mtor that has high voltage or high inductance rating) will be slow, and while the top speed is theoretically capable, you will see in real life that the acceleration is very poor resulting in skipped steps even when you have the amperage maxed out.

So, for the two motors you have shown the speed should be good enough for most axis except for a geared extruder (wades) setup. Its then just a matter of having to get DRV8825 drivers.

Thanks for info. I know that Rumba and most, if not all, other controllers cant support motors beyond 2A. Speed vs torque is important balance; however with higher gear ratio, i should be, in theory, able to convert torque to speed to ballance the two out.
Good point about inductance, vs acceleration. That i did not think about.

P.S. My main computer is a water cooled beast, pulling 1.2KW at the wall; so i have no objections to adding a fan or two to the printer controller assembly. This build is still just a theoretical design and my parts budget is $1,000. So, i am open to, and appreciate any and all suggestions.

The first motor you speced has an Amp rating of 1.7Amps. Without proper cooling, the A4988 drivers will not handle that well. The second motor is 2 Amps. That is the maximum rating for the DRV8825 drivers. We wont even bother talking about the 3Amp motor.

You should also know that when dealing with motors, speed can become a concern too. Higher-torque motors are often slower. You can determine their speed using this calculator:

http://www.daycounter.com/Calculators/S … ator.phtml

The speed rating isbased upon voltage, amperage, and the inductance of the motor. As long as the calculator shows the motor is capabe of at least 1 revolution/second, you should be fine (most motors rated under 2 amps are good). If it is not (mtor that has high voltage or high inductance rating) will be slow, and while the top speed is theoretically capable, you will see in real life that the acceleration is very poor resulting in skipped steps even when you have the amperage maxed out.

So, for the two motors you have shown the speed should be good enough for most axis except for a geared extruder (wades) setup. Its then just a matter of having to get DRV8825 drivers.

Ok - just bear in mind there is a lot more to motor selection than just torque.. Rotor Inertia, resistance, size, etc..
Maybe spend some time researching what is in a motor, and how to best choose a motor for 3D printing... as there is a bit to it and its not just 'big numbers = good'..

Also - word to the wise - you need to expand your search beyond Amazon... several of those motors are marked up hugely and are just 'sell through' from sparkfun..

E.g, the 125oz-in, is *really* sold from Sparkfun.. Amazon wants $27.95 + $7.93 shipping. Sprkfun wants $23.
Sparkfun will also ship free on order of $60 or more.. so buy 3 motors, get them shipped free for $69.. the same motors from Sparkfun bought via your Amazon link would be $107.64
https://www.sparkfun.com/products/10847

The 58oz-in.. is really a 68oz-in, and it costs $16.95 at Sparkfun, or $22.94 via Amazon.
https://www.sparkfun.com/products/10846

These aren't 'similar' motors - if you follow back the Amazon goods you'll see they are the exact same sparkfun ones sourced from sparkfun often via another retailer.....

Bottom line - Amazon is not the place to search for stepper motors - and its not just about numbers for holding torque...

Re 'indirect drive' - Its referred to as Bowden Drive/Setup/Extrusion, and its very very common. Might want to do a bit of research in that area too.

Thanks for the insight. I have Amazon Prime, which is why i start there; i get free 2d shipping on most things, but i hear what you are saying about buying direct from sparkfun.

I realize that there is more than big numbers = good; impedance, current draw etc are all important factors; which is why i started another thread asking for "best controller for home-brew" to be able to accept as wide of the range of the motors as possible.

Also - word to the wise - you need to expand your search beyond Amazon... several of those motors are marked up hugely and are just 'sell through' from sparkfun..

E.g, the 125oz-in, is *really* sold from Sparkfun.. Amazon wants $27.95 + $7.93 shipping. Sprkfun wants $23.
Sparkfun will also ship free on order of $60 or more.. so buy 3 motors, get them shipped free for $69.. the same motors from Sparkfun bought via your Amazon link would be $107.64
https://www.sparkfun.com/products/10847

The 58oz-in.. is really a 68oz-in, and it costs $16.95 at Sparkfun, or $22.94 via Amazon.
https://www.sparkfun.com/products/10846

These aren't 'similar' motors - if you follow back the Amazon goods you'll see they are the exact same sparkfun ones sourced from sparkfun often via another retailer.....

Bottom line - Amazon is not the place to search for stepper motors - and its not just about numbers for holding torque...

Re 'indirect drive' - Its referred to as Bowden Drive/Setup/Extrusion, and its very very common. Might want to do a bit of research in that area too.

There are many motor options, ranging from 58in-oz to 200+in-oz

58 http://www.amazon.com/Stepper-Motor-oz- … pper+motor
125 http://www.amazon.com/Stepper-Motor-125 … s_indust_6
257 http://www.amazon.com/NEMA-257oz-Steppe … s_indust_8

So as long as the controller can drive them, this is why i am leaning towards Rumba,  weight of the head should not be an issue.

Indirect drive sounds interesting, I have not thought of doing that, but i am wondering if there would be any issues with feed rate control?

http://manual.slic3r.org/MultipleExtruders.html

Specifically the end part about AFM and multimaterial.

http://www.ebay.com/itm/DUAL-HEAD-ALL-M … 1396100624

What do you all think? I've never heard of this company before, but pictures sure look nice...
I want to be able to print to 300C+ so not sure what temp range the above linked hot end can deliver. Pico should be able to go to 500C with thermistor upgrade. Now limited by thermistor to 300C.

I am planning to be running all this off RUMBA board; unless someone can suggest higher quality options. This is intended to be quality build, not a cheap build.

Thanks ahead.