MK7 extruder drive gear

If any one is using a direct drive bowden set up, where have you sourced your MK7 drive gears from?
Preferably in the U.S., but listing all the other sources may help people in other parts of the world too.

 

I guess no one uses a Bowden direct drive setup.
I came across a couple of drive wheels from a Miller extended reach welding gun. They are 13mm outer diameter and a 6mm(1/4 inch) bore. They are a bit pricey at $14 a pop, but they are made out of tool; steel and not likely to wear out of plastic.
The Miller part #136435 is for .060(SAE) Aluminum wire. NEMA 23 steppers have a 6mm shaft so I'm considering these for my drive bowden drives. What say you?

 

I got my drive gears from SeeMeCNC with my EZStruders. I bored them out to 6mm on a lathe but you probably don't need to use a lathe for it.

I would not recommend the EZStruders however

 

I'm going to build my own extruders. NEMA 23 steppers have 6mm shafts, and I found a daisy chain direct drive stl on thingiverse.
http://www.thingiverse.com/thing:366280

 

Jesus, why nema 23? This is my setup: https://plus.google.com/+MikeKelly04/posts/YAVECnbT3ZS

 

one reason is they have 6mm shafts, so I won't need an adapter for my mig feeder drive wheels. Second is they have much higher torque so they won't actually be working as hard, as a NEMA 17 stepper. I've been reading where people have been needing to use geared steppers to drive the filament at higher feed rates, this eliminates that problem and reduces the number of moving parts to wear out. The ones I ordered are 156 oz/in 2.5A steppers.
Other considerations are for some multiple nozzle systems I have in mind, for a much larger printer/router setup, so being able to push the filament over a greater distance reliably is also a factor.