I am looking to use a nem17 Stepper Motor with a limit switch and am wondering what is the suggested driver to use.
My project would be a model railway turntable HO scale.
Use a stepper driver (there are many out there) which can handle the rated current of your stepper.
That last parameter is key to giving you specific suggestions.
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NEMA 17 is merely physical data as to motor dimensions. Using a stepper motor you look at your motor rated voltage and current and choose a driver based on motor current and voltage for your chosen motor.
You aren't looking at much torque required for your project and you choose a motor based on how much torque you need to get done whatever you want done. 
Ron
A turntable requires a relatively high resolution of the stepper motor positions. You should consider a gear wheel or a toothed belt drive with a high reduction ratio.
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Ok I have a Nano, NEM 17, L298N with a gear wheel and belt - I am hoping to use MobaTools.
Probably an overkill for my current project but will allow for expansion later on.
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This will not work. Get some cheap TB6600 like https://www.amazon.de/dp/B0CD745WY8 or a CNC-Shield+drivers or some of these https://www.amazon.de/dp/B07VGV1XFT - they just need 5V and are enough for H0 turntable.
I tried the uln2003 with that motor but it didn't have enough torque to move the limit switch
As already mentioned - most NEMA17 steppers connot be driven by the L298.
Please post the technical data of your stepper to select a suitable driver.
MobaTools was originally developed with such applications in mind 
You must not place them in the center of the table, but on the rim, driving the table with a 1:10 or more ratio. And you need easy to operate limit switches, closed by default.
This is the link to the stepper motor
(Pack of 2pcs) NEMA17 Stepper Motor High Torque Bipolar DC Step Motor Kit for CNC XYZ 3D Printer : Amazon.ca: Industrial & Scientific
This is the link to the limit switch
[Twidec / 10Pcs Micro Limit Switch Long Hinge Roller Arm Switch for Arduino V-156-1C25 : Amazon.ca: Industrial & Scientific](https://www.amazon.ca/dp/B07NVD5LGM?
psc=1&ref=ppx_yo2ov_dt_b_product_details)
The L298N and the NANO I already have.
This is the wheel I have and was hoping to use - thanks for the tip as to where to place the limit switch.
Houkr GT2 Aluminum Timing Belt Idler Pulley Bearing 20&60 Teeth Width 6.35mm Born Synchronous Wheel, with a Length 200mm Width 6mm Belt and a M4 Allen Wrench, for 3D Printer. : Amazon.ca: Industrial & Scientific
Does it make much difference NC or NO as default I have been testing using NO
NC takes almost no force to open, while NO takes a lot of travel plus some force to close.
Ok thanks i will see if I can pick one up.
That is interesting to know - any more you can pass along - would be appreciated?
The A4988 or DRV8825 current limiting stepper drivers will both work with those motors. Pololu has the best selection. Be sure to follow their instructions to set the current limit to 1 Ampere or less.
What is the diameter of your turntable? If we talk about a ( small ) 23m turntable, this are ~26cm in H0 gauge. This means a circumference of 83cm. To position the rails exactly, you need a positional accuracy of less than 1mm - say 0.5mm , what means 1660 steps per rev!!.
Your belt drive has a reduction ratio of 3:1 and your stepper has 200 steps/rev what means 600 steps/rev. That is far too few. When using the current driver suggested by @jremington you can use microstepping, but the microstep positions aren't that exact as the full step positions. I would suggest a much greater mechanical reduction ratio.
It is 23cm diameter - [quote="MicroBahner, post:18, topic:1222369"]
I would suggest a much greater mechanical reduction ratio.
[/quote]
What would be the proper reduction ratio - or recommended item
Do the math... go from 200 steps to 1660 steps means just over 1:8.
Turntables like that would have to rotate at no more than 2-3 rpm, which is already way faster than real life.
A typical stepper can easily reach 1000 rpm, likely double that. You can use 1:500 gearing on that.
For your project, 1:100 sounds good. Easy to get when you run the thing from the edge as suggested before.
Considering these speeds and the light duty of an HO size turntable, the venerable 28BYJ-48 stepper should be considered. It's really small, makes 2048 steps per revolution, maximum about 30 rpm but that's pushing it, up to 20 rpm is no problem. Those little things would be a good choice in combination with a 1:3-1:5 gearing ratio.
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