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New source of SY42STH47-1206A

Posted by RyanTM 
New source of SY42STH47-1206A
November 02, 2010 01:07PM

This is Ryan from Pololu. I wanted to announce that we are now offering Soyo's SY42STH47-1206A stepper motor for sale. This is the version with the single shaft. From my research on the RepRap Wiki, I saw that the dual shaft is required for one of the stepper motors on the Darwin, and from this RepRap forum post, it seems that the dual shaft is not required on the Mendel. Is my understanding correct? Do people still typically buy dual-shaft steppers when making a Mendel even though they are not strictly required? If there is anything that you'd like to see from U.S. stepper motor suppliers, I would be interested to hear it.

Ryan Mulligan
Re: New source of SY42STH47-1206A
November 02, 2010 06:26PM
Hi Ryan,

From what I can gather, one of the reasons originally was that with dual-shaft steppers, you had the option of putting an encoder on the other side. This was eventually deemed unnecessary however. Some people also thought about putting a small fan blade on it, but it would only operate when the motor spins, which is not very useful.

Dual shaft is quite useful for experimenters though as:

1. You can cut/file/spline/knurl/etc each shaft differently for a different job. Eg: You have two types of extruder head, each one with a different drive gear. As you've got a dual shaft motor, you can put each gear on opposite ends of the motor, and swap the motor between extruders. You will of course most likely have to reverse your wiring between them (depends on the extruder).
2. When modifying the shaft on a motor for any reason, you can hold the other shaft in a vice. This is probably the most important thing for people unsure of their mechanical skills to be honest, as it's a lot easier to file a flat or cut splines in a motor this way. That said, since almost everyone is now making/going for for gears with grub screws in them (easier to construct), it may simply be better to look at a D shaped shaft with a flat in them as an option.

FWIW: I didn't buy dual shaft motors. Partially because here in Australia I didn't find a cheap source of them, and partially because they didn't seem to be needed. I also know I've got enough mechanical skill to take care of such things, so for me it was a no brainer.
Re: New source of SY42STH47-1206A
November 03, 2010 03:19AM
If you get the second shaft for free, there's noe reason not to grab it. But I'm pretty sure almost nobody would buy dual-shaft motors if they'd cost 1 dollar more than the single-shaft counterpart.

Generation 7 Electronics Teacup Firmware RepRap DIY
Re: New source of SY42STH47-1206A
November 03, 2010 03:30AM
The Darwin specified a dual shaft for the Z axis because it needed the shaft on the opposite side of the motor from the mount; you could get around it with long bolts though.

No need for dual shafts on Mendel; I do like to use 5 kg*cm Nema 17's for my extruders, but 3 kg*cm should be OK. Eventually someone will gear the extruder down even more, reducing the torque required even further.

Re: New source of SY42STH47-1206A
November 03, 2010 07:28AM
Hello, good morning.
I´m interested in this stepper motor, but i have a question about SY42STH47-1206A stepper motor.
I thought that this stepper motor is a unipolar motor because it has 6 wires.
It may be hybrid?
In this case, what would be the configuration for use bipolar?
Re: New source of SY42STH47-1206A
November 03, 2010 10:03AM

In this case, what would be the configuration for use bipolar?

Just ignore wires 5 and 6, the wires connected to the middle of each coil.

Generation 7 Electronics Teacup Firmware RepRap DIY
Re: New source of SY42STH47-1206A
June 04, 2011 01:42PM
Ryan TM thank's
This is help full to me as i want to buy from a US supplier to keep my shipping cost down.
the visual guide i have shows single shaft motors. so that is what i want.

But your friends at Pololu say they are back ordered. and to chose another motor.eye rolling smiley
with out a recommendation IE something like "Use this(#?) motor as it is nearly the same or will work the same in your application".
a close enough for gumet work. type thing.
i will need 5 motors while there can be slight differences 2 must be the same.

i would gladly order from you and still might but i don't want to read all the data sheets for all motors available.confused smiley
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