Would you buy a Stepper Motor without a Data Sheet?

[ukee1593]

So I'm looking at buying some stepper motors for some miscellaneous projects (powering a robot, or a small PCB CNC) and have found a few on Ebay.  The only problem is one that I found doesn't have a datasheet available. 

I'm looking for decent power in a small size. 

Here is the one with a data sheet: http://www.ebay.com.au/itm/Sanyo-2-Phase-42MM-Square-Step-Stepper-Motors-103H5208-Haunted-House-Props-NEW-/290941313226?pt=LH_DefaultDomain_0&hash=item43bd7420ca

Here is the one which I cannot find a data sheet on: http://www.ebay.com.au/itm/Sanyo-1-1-Amp-Stepper-Motors-200-Step-DIY-CNC-Router-103-775-7241-1-8-Degree-NEW-/300930708333?pt=LH_DefaultDomain_0&hash=item4610de336d

The thought of dealing with a stepper motor without a datasheet scares me a little.  I know it is possible (as lots of people pull these out of old printers and use them for projects) but it would be nice to be able to read off the datasheet to make it easier to drive the motor.  (and no, I don't have access to any old printers unfortunately)

Also, I'm not even sure which stepper is more powerful ... I'd assume that the first one (the one with the data sheet) is actually less powerful but I don't know for sure?

Any suggestions?

[michaelym]

The info on the item page on eBay, is basically what you get on a stepper motor datasheet.
Look at some on Digi-key on you will see what i am talking about.

What you need to look at, is the driver IC datasheet

[ukee1593]

Thanks for replying ...

The first listing (which included a datasheet) is brilliant ... It gives me all the specs of the motor and everything. 

But the second one: http://www.ebay.com/itm/Sanyo-1-1-Amp-Stepper-Motors-200-Step-DIY-CNC-Router-103-775-7241-1-8-Degree-NEW-/300930708333?pt=LH_DefaultDomain_0&hash=item4610de336d tells me almost nothing.  From what I can see it gives the step angle, and the current ... but is that the unipolar current, or the bipolar current?  Heck the weight isn't even displayed (but I think it is about 1.2 pound from the shipping details). 

As for the drivers, I took a look at the drivers suggested for other stepper, but I was planning on designing my own driver as a bit of a challenge/project!

As I said before, I'm still not sure which stepper is more powerful.  If the 1.1 amp is the bipolar rating then it will be more powerful, but if its the unipolar rating then it will be less powerful AFAIK.