Tom McWire vs. Tach42 vs. Other?

[Jesse B]

In my search for an inexpensive all-in-one stepper motor controller to build, I seem to have narrowed it down to two choices, which are as follows:

Tom McWire's Instructables Motor Controller
or
Tach42 3-Axis Board

Is either of these better than the other? If so, why?

I'm also open to suggestions, but they have to be as inexpensive as possible. I need at least 1.5A per coil. I also have pretty much every connector on my PC's that you can think of

Thanks,

- Jesse

[pminmo]

Same basic operation, two phase full step, same performance issues. The light bulb current limiter on the mcwire is motor dependent, and unpredictable for different motors.

[Jesse B]

Same basic operation, two phase full step, same performance issues. The light bulb current limiter on the mcwire is motor dependent, and unpredictable for different motors.

If I were to calculate the proper specs for a resistor would it still be similar? Or should I just go with the Tach42 due to the proven layout and lack of iffy-lightbulbs? Also, what are these 'performance issues' you speak of? Are they bad enough to not build this board for a first time CNC builder, or will it be adequate?

Thanks

[pminmo]

If I were to calculate the proper specs for a resistor would it still be similar?

Probably not, it depends on the motor, power supply, and light bulb.

Also, what are these 'performance issues' you speak of?
Thanks

Its a full step board, steppers are the most prone to resonance in full step, so rpm's are limited. It them boils down to what kind of performance you want, how big the machine is, what kind of rotary to linear conversion is done.

[Jesse B]

Probably not, it depends on the motor, power supply, and light bulb.

Its a full step board, steppers are the most prone to resonance in full step, so rpm's are limited. It them boils down to what kind of performance you want, how big the machine is, what kind of rotary to linear conversion is done.

The machine is fairly small, and is <= 2' in all dimensions. The linear travel is approximately as follows (note that these are just guesses, as the machine is only designed in CAD and has not been made yet):

X-Axis: 9"
Y-Axis: 11"
Z-Axis: 3-4"

As you can see it's a fairly small machine. I for performance I just need the best I can get for as little money as possible. I'm sure that I will someday upgrade to a better, larger design, but this controller has to last me for now.

[pminmo]

Save yourself some heartache and get a hobbycnc kit.

[Jesse B]

But that costs more money and isn't any fun

Is this the kit you're speaking of? http://www.hobbycnc.com/products/hob...er-board-kits/

[pminmo]

yes

[Jesse B]

yes

Okay, thanks Any other decent drivers out there, or am I just gonna have to cough up the cash for this one? If you haven't realized yet, cash is kind of short

[pminmo]

You can build the full step board it works, it's just that your going to wind up spending $30 in parts and won't get much in the way of rapids. Of course in 11" your don't have far to travel. If your screw pitch is steep it would work better. So if the price difference is important.....

[Jesse B]

You can build the full step board it works, it's just that your going to wind up spending $30 in parts and won't get much in the way of rapids. Of course in 11" your don't have far to travel. If your screw pitch is steep it would work better. So if the price difference is important.....

Well just due to my lack of general knowledge, I'm not sure if it'd be better to build a less expensive controller now, then buy a better one if/when I upgrade, or to just suck it up and buy a better controller now. As long as that controller will last, and be able to take almost anything I throw at it, it may be worth the extra money. It's just over double the price, and with money as tight as it is right now, I'm just unsure whether or not the cost is justifiable. As I said, I'm new, so don't make fun of me if this sounds dumb!

[pminmo]

Well the SLA's on the hcnc board won't take anything you throw at them. And when you goof with back emf or overvoltage there is a good chance of damage.