Looking for motor shield to control steppers

I am pretty new to arduino so bare with me. I have an arduino uno i plan on using to control two stepper motors(one of them will be a lead screw). however i am unsure what my best options are for motor shields... i have been looking into the L293D and the Pololu A4988 motor driver shields but im not sure which one if either of them is going to be best for my application. The lead screw motor i need to use is a bipolar 200 steps/rev 1.7amps/Phase at 2.8v. Here is the link

https://www.pololu.com/product/2689

The other stepper motor i am using is a hybrid stepper motor 200 steps/rev and draws 1amp/Phase at 7.4v. Here is the link

https://www.pololu.com/product/1472

My concern is after reading through the stepper motor basics thread it recommends not to use the H bridge like the L293D because they cannot limit current or operate with high voltages and i will need to turn the regular stepper motor at a higher RPM. Also as a side note can i run one stepper motor and a bi directional dc motor off of one motor shield or would i need two shields??? THANKS GUYS

dwilk936: My concern is after reading through the stepper motor basics thread ....

I had hoped that you would have concluded from that Thread that you need an A4988 or DRV8825 for each motor. The DRV8825 would be better for the high current motor.

Let me know if there is something in that Thread that needs further clarification.

Deal with your DC motor separately with a suitable h-bridge driver.

...R

That thread was great it was very helpful I got a lot of good information from it, and yes after I posted this I did a little more research and realized I will need a DRV8825 to power the bigger motor. Another question I have is should I run my dc motor through an H bridge driver like the L293D or through two SPDT relays. What are the pros and cons of each I need to be able to control the motor fwd, rev and off but not coast I need it to hold the weight of the load. I was told 2 SPDT relays are good for this application but I'm open to the use of an H bridge if it will work.

If you are driving a leadscrew you need as much speed as you can get, meaning low-impedance
bipolar steppers, chopper-driver and high voltage supply. A4988 at 24V or higher
would be a starting point for a small stepper (NEMA17). Stepper motor impedance
should be less than 5 ohms, so your first motor is a good choice. Other possible
drivers are DRV8825 (better at high current like 1.7A which is a bit beyond the A4988)

All the single chip stepper drivers are inefficient and will get hot you need to consider
active cooling.

You need 2 H-bridges to drive one stepper. I would suggest using DRV8825 for
both steppers, fewer pins needed on the Arduino.

What is the DC motor?

If you only need the motor to be full forward or full reverse relays will work. But a h-bridge driver would probably be easier to use and gives the option of speed control. Whether an L293 is appropriate depends on your motor. AFAIK the L293 is very inefficient as it uses transistors rather than mosfets.

...R

Ok thanks guys. I believe i have what i need for the lead screw stepper the problem im having now is finding a DC motor that has the torque output i need. For this project i need 50 in lbs of torque from the motor. however i could use two motors with 25 in lbs of torque a piece but i would need another H bridge which takes up more pins from the arduino or can i run them both off of the same H Bridge since they will be acting together and performing the same commands. All of the torque specs i am getting for these DC motors is STALL torque and im not sure how that relates to dynamic torque. Any suggestions on where i could find low RPM high torque DC motors. Can i use any 12v or 24v DC motor or would a brushed DC be better. THANKS FOR ALL THE HELP

50 lbf-in is 5.7Nm is earth units, which is a huge motor - you need reduction gearing.

The volume of a motor is directly related to its max torque by the laws of physics(*)
so the only solution is reduction gearing of some sort.

For a DC motor stall torque is the same as dynamic torque across most of the speed
range - both just depend on the current flowing.

A DC motor and a brushed DC motor are the same thing.

(*) for a cylindrical rotor - the max tangential force per unit area of rotor is limited
by the properties of iron and copper until you go to superconducting motors.