innovate wrote:Yes - but you really only want to do the extruder as 1/32... running the other axi' at 1/32 is tempting, but it actually has other complications with torque derating that you are best off avoiding by sticking to 1/16 on those torque-demanding axi. I have 1/16 A4988's on X,Y and Z, and a 1/32 on E0/E1 ...
Hello Adrian, so you don't recommend adding DRV8825 drivers on the X,Y, and Z? I just received my Ramps 1.4 kit with 4 DRV8825 drivers.
I wouldn't run out to get them to replace the A498X's , but if thats what you've got (4 x DRV8825) thats what you've got... However I would be ready to reconfigure the jumpers to downgrade them to 1/16 stepping if there is even the slightest sign of a missed step.
The long winded reason is:
1/32 microstepping gives you more 'positions' between full-steps (which are 1.8°), This INCREASES Resolution. Good! 
1/32 microstepping with its increased 'Resolution' will actually DECREASE Accuracy. Bad! - "Huh?" You say ?
- Stepper motors have poor 'mid-step' accuracy. So Microstepping a 1.8° Stepper you don't actaully get 32 x 0.05626°, some of those might be 0.06° Steps, some might be 0.050°. Load Torque will also cause 'backlash' in the rotor of the stepper in microstepping, offsetting the rotor from its intended position until the torque is sufficent to actually move it where it was supposed to - having now missed several steps potentially...
1/32 microstepping decreases the Torque compared to 1/16..
- At 1/16, you get ~10% of the "Full Step Holding Torque" of the stepper
- At 1/32, you get ~5% of the "Full Step Holding Torque" of the stepper.
So whats this got to do with accuracy?
If the load torque plus the steppers friction torque is greater than the incremental torque of a microstep - additional microsteps will need to occur until the accumulated torque exceeds the load torque plus the steppers friction torque. Basically, sending a microstep does not mean the motor will actually move! - BAD! 
And if changing direction, a huge number of microsteps may be needed before movement in the correct direction occurs. - VERY BAD!
All of the above is *irrelevant* if you had say 423 Oz-In NEMA23's driving the axi' on the Solidoodle. But we don't. We instead have a Y-Axis being driven pretty hard, and an X-Axis already being run over-spec. Reducing the Torque available to move the respective already at 'max' axi' is not a road I feel will lead you to paradise - Particularly in the X-Axis 
Anyway - give it a go.. but if you see missed steps or alignment issues - reduce the stepping to 1/16 and go from there.
