I've been having trouble with the spring.
Since the spring curves at an arch, I feel like it's not applying enough pressure on the arm. I used the spring that everyone has been recommending (McMaster-Carr #9657K331, 0.3" 0.032" 0.36" 7.69 8.60 12 9657K331 9.80)
Anyone have recommendations on this, or perhaps the model for a stronger spring?
Emmet, you mentioned you used a Utility Compression Spring C-614. What store did you buy that at? I'm having trouble finding it. I am trying to figure out what it's spring load rate is, to determine if it will be stronger than the 8.6lb/inch rate for the #9657K331 compression spring I purchased.
I did find a compression spring marked as C-614 from a 3rd party Amazon seller, but I'd rather go to the store than wait a week for delivery.http://www.amazon.com/Century-Spring-C-614-Compression-display/dp/B000H5SKLE/ref=sr_1_1?s=industrial&ie=UTF8&qid=1418965359&sr=1-1&keywords=compression+Spring+C-614
Essentially what I've noticed is that with my current spring, my filament feeding is inconsistent: often the filament travels just fine, and I can see the stepper motor and the bearing both rotating, but then intermittently the bearing will just stop moving. If I use my thumb to aid the spring in applying more pressure, the bearing starts moving again.