Where can I buy a “pancake” stepper motor at an acceptable price? Like the NEMA17 12mm thin in the picture
20mm NEMA17 motors are easy to find - not so much 12mm ones. RS has one, but it’s 38GBP, which i guess is fair for such a highly specialized product.
Edit: forgot the link: http://uk.rs-online.com/web/p/stepper-motors/8293538/
Also notice, those are 24V motors, and only got a holding torque of 0.083Nm, what are you going to use it for?
@Michael_Andresen it’s 24V max (dynamically). Its static resistance is 3.5Ohm, which makes it 3.5V @1A at idle. 0.083Nm is not much worse than the 0.13Nm from a 20mm motor, so i guess it would be fine for a light z-axis or a heavily geared extruder?
This Sanyo model has such a short shaft that it really limits options. A bummer since that Sanyo series has the best torque per weight I’ve seen in the size class by a large margin.
I’m using these for a geared extruder (13/60). They work but they can burn out from heat, I recommend heatsink+fan on them.
I’ve bought from farnell and http://tme.eu.
I’ve also tested some round nema14 alternatives, but they are not quite as good. The 100g model is ok though.
@Oystein_Krog Sounds more like that size is not well-suited for the task if you have to crank it up that much, and heat sinks defeat the point of going with a super light motor. Motors shouldn’t burn up if they’re up to the task, Sanyo does offer a size or two larger.
@Jeff_DeMaagd Indeed, but I’m going to some extremes to cut down mass, so I’m making them work. A heatsink+fan add much less mass than a bigger motor. Only time will tell if it works long-term.
They do offer a 140g version.
That is too heavy for me 
It seems like flatness is what @Rene_Jurack is going for, but if you just want a light motor @Oystein_Krog , then there are plenty of options available in NEMA14 or even NEMA8.
@Thomas_Sanladerer Yeah I’ve been testing some round Nema14’s. They are promising, but the smallest of them is a little bit too weak I think. Not any better than this motor though as far as I can tell (except price).
I am somewhat constrained by flatness but not critically. One of those long Nema8’s might be too much though.
Do you know of any in particular that you can recommend?
I’ve seen the guys with UM’s that use Nema8’s + worm gears, but that seem like a lot of trouble.
I want to reach the holy grail; bowden-like motion performance with on-carriage extruder
I’ve also been following the reprap thread with the guys testing small servos for extruders, this seems extremely promising but I will wait a little bit and see what they land on before I get into it myself… too many projects:P
I have something in mind that involves the E3D Titan and a “light as possible” Nema17 to put both as a direct-extruder on the printing carriage. The plans I have with this setup are benefiting from a “flat as possible” motor more, than from a “light as possible”. Thats why I’m looking for a flat one. A “standard” Nema17 is no option. All this in mind, the stepper still needs to drive the Titan flawlessly…
Yeah the quest for as “light as possible” is my current focus as well.
I’m not sure I would use this stepper on the Titan. It barely works in my extruder with 60:13 gearing, I suspect the Titans 3:1 is not enough, but it may be that my design/prints have more friction than the Titan.
My ideal extruder is:
- Bondtech dual gears.
- Micro-servo w/encoder.
So far I’m just using MK7/MK8 gears with a light-weight stepper though:P
I’ve got vertical rails, and my current design places the stepper motor and gears behind/on the carriage, with the drive gear on a rod that goes through the carriage.
I have some posts showing older versions of the design, and my entire printer is fully modeled in openscad, available on my github.
My next step is to order 5mm ID bondtech gears and use them in my extruder 
Then next… servo motors
@Thomas_Sanladerer found some today at http://ebay.de for 12.50€ -> http://goo.gl/68v5B8
@Rene_Jurack that’s the exact on i used with the titan, but they are 20mm thick (and heavier). I thought you were looking for the super-flat ones?
I am, but there is no way I am going to pay 45$ per motor + shipping 