stepper motor bulk purchase

Any further problems/comments about the KL23H251-24-8B? (11A from Keling) I'm about to drop $80, so I just wanted to double check...
Thanks!

[www.kelinginc.net]

I gather you're going to wire it in series to keep the phase amperage down below 2 amps?

Are you using this thing to drive a Darwin or your own design that, iirc, uses threaded rods?

Forest,
I was going to use them for the McWire Cartesian Bot (threaded rods). Bad idea? Would you recommend something else? Less amps?
Thanks!

I frankly don't know how much torque it takes to run the McWire Cartesian Bot. I do know from experience, however, that when you specify a 1.8 degree step stepper motor you are going to have the devil's own time getting it to turn fast enough to do any printing in a reasonable amount of time. Figure that you have 200 steps per revolution and 1 mm pitch on your threaded rod. That means that one step moves you 0.005 mm. If you do 1,000 steps/sec you are going to be moving your axis 5 mm/sec. Getting a stepper motor to do 1000 steps/sec is hard work. Ask Zach or nophead or anybody who's worked with them.

Also, when you are running at 1000 steps/second and more your available torque drops like a stone, so that big holding torque value and all that power isn't getting you very much at speeds high enough to get some printing done in reasonable time frames.

What I did was opt for a smaller stepper with as big a step as I could buy with a low inductance. It runs fast and the transition per step for the one I bought is like 0.04 mm/step. That's twice as good as I need. Your needs may differ, though.

i'm using the keling ones on my mcwire and it moves just fine. at this point in time, i dont think the movement speed is the biggest issue we're dealing with.

hey could someone suggest stepper motors (other than the ones that Zach was selling) for mcwire that will work decently with the current standard power supply, arduino electronics, etc and will be shipped from the us?? Optimally I'd receive them before the end of March.

I am using .9 degree Darwin clone steppers from oriental motor.
Using the Darwin Pic steppers I have not been able to get enough speed to build anything with my McWire Repstrap. Too much plastic not enough speed. The Keling motors should be faster , but not enough faster IMHO. I designed and build a belt drive mod for my McWire that has the same speed ratios for X and Y as Darwin. Now all I need is a little free time to tidy up and debug the finished product. Sadly free time is a little short for me right now. The design is pretty obvious, a pulley on the stepper an Idler pulley and washers on a bolt, mounting plates for both and a belt clamp that captures both ends of the belt and is attached to the X or Y stage.

Dan

"Using the Darwin Pic steppers I have not been able to get enough speed to build anything with my McWire Repstrap."

That's what I suspected was going to happen. You just have to pry too many steps/second out of one of those beefy, 0.9-1.8 degree steppers for it to be practical with a threaded rod drive system to get the speeds you need for an extruder.

balm Wrote:
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> Any further problems/comments about the
> KL23H251-24-8B? (11A from Keling) I'm about to
> drop $80, so I just wanted to double check...
> Thanks!

I bought 3 of these exact same motors a couple of years ago and they are amazingly good value - I abused them with a crappy driver and they're still going strong!