As previously noted, my Simple’s effective build area is only 88mm along the X axis. I found some 8mm hardened steel rods and some 2mm spaced timing belts (from old printers / scanners) and figured all I need is the GT2 pulley and I can work on extending the X axis.
In Tinkercad I found a GT2 gear and cleaned it up a bit: https://tinkercad.com/things/dwB3hLGXu0S
However, as you can see in the photos, the printer is running some kind of extra pass around the outside of the teeth creating a messy web of fine filament. What Slic3r settings would you recommend to stop that.
Or am I simply pushing beyond the limits of this little printer?
Looks like stringing. Maybe you’re running a bit hot, or with too little retraction. That said, I’m not sure I’d be able to print a GT2 gear at a usable resolution on my PB-S.
It’s worth it to buy one online for $5 or less if you can’t find one in your printers/scanners. If you scavenged the belt, what was driving it? There should be a gear in there somewhere!
The stringing seems to be caused by the Slic3r / g-code attempting to “cap” each tooth. While printing it looks like a useable set of teeth as it’s wiggling back and forth around the edge and then it goes back and tries to touch up each tooth - so yeah, there’s probably too little retraction, printing too fast, etc - personally I think it would be close if I could just drop the “capping”.
Buying vs printing - Don’t you see?!? I have a printer dang it! 
I have the original pulley/gears that drove the belts, but they are the wrong size.
Is it putting a small dab of infill in each tooth? Try the “avoid crossing perimeters” setting in slic3r.
As to your print it seems like multiple problems. first you seem to have slop either in X or Y or both. This could be loose string slipping on the sand paper, or some other place where your axis is aloud to move around. Second you could slow down your print speed to gain better accuracy, and third you should add some retract to your print but from what i see not sure it will help here to increase the look of the gear. For this part i think you should buy a set. not sure printed parts will give you the accuracy required for your printer. cheers
I had similar issue with Slic3r, I sliced my tooth gears with Cura, printed without issues.
I would say its not printing a cap for the layers. It is oozing what looks like PLA and leaving stringers as the nozzle moves. Recheck all calibrations, but you could try lowering the temp and upping the retraction if you like. That may get you somewhere for now.
Hi, I think there are multiple issues, but the slicing one which is doing the capping can be sorted out by changing some settings in the gear itself, you should try downloading the openscad gearmaking thing http://www.thingiverse.com/thing:52320 which has all these options for how far in each tooth goes and then in Slic3r or whatever you use, change the width of your extrusion to match (try adjusting in increments of 0.1 starting at around your nozzle thickness going out to see the differences - it’s in the advanced options) the rather than printing it, use a G-Code viewer to inspect it and see if the extra loop is gone, then at least you have a good G-codebase to start from to figure out the other issues. Do you think I’m on the right track?..
Oh, and print a bunch of them at the same time, real slow with good cooling…
