Welcome to the SeeMeCNC Community

So other people can avoid my braindead stupidity.
I've been trying to print a couple of reel holders for the last couple of days, I could print the first couple of layers and then I'd comeback, check on it and the infill and sometimes the edges would be horribly messed up, what looked like either starving of filament, or not sticking together.
I must have started 10 of these before I realized what was actually happening, it wasn't a PLA jam, it wan't a temperature issue, the filament roller was not too loose.

The filament roller was too tight, I finally watched the first couple of hours of the print today and what was happening is that the filament would stop feeding consistently at some point during the print. When it happened I loosened the tension bolts on the extruder about half a turn and it was fine for the rest of the print.

I believe the issue is that there is enough variation in the diameter of the filament that if you have it too tight, it will feed for some period and then hit a slightly wider section of the filament and be unable to pull it through the roller.

Hopefully it will help someone else who has filament feeding issues out.

My experience was that the stepper warmed the plastic frame and allowed the gears to skip easier. I screwed (replaced a screw on the back of the stepper with a longer 1) a little piece of angled sheetmetal on the tail of the stepper to brace it against the plastic. I installed a 40mm fan directed at the back of the stepper and it also flows into the roller and top of hot end area. This eliminated all off my drive slipping and filament melting issues. I also made a fan duct from Thingiverse (Brix's Adjustable Fan Mount http://www.thingiverse.com/thing:20830) and installed it for cooling the print. It helped with bridging very well. I also heated a piece of glass with a pencil styled heat gun to use as a heated bed just for the print to start and adhere. It turned out very flat and had to be pryed off. I couldnt believe the adhesion. Nothing scientifc either, I could have used a blow dryer on hot. Once the bed was hot to touch, not scorching just hot I started printing. It really helps the corners and the print staying flat.

I put a piece of 7x7.5x3/16 tempered glass on my homemade heated bed, and with PLA I find getting the first layer to stick with the glass at 60C is dramatically easier and once the glass cools below about 30C or so the prints pretty much separate themselves. It's also evident how not straight my AL plate was :/
Wish I'd done it sooner.
On the filament issue, my extruder stepper doesn't even get warm, and I've previously done several multi hour prints without issue. I do have a 40mm fan pointed at the top of the extruder (which seems to have fixed my jamming problem with PLA) I wouldn't rule out it being heat related though, certainly possible.
What triggered the issue above was I moved the printer, and in doing so removed the filament, I just tightened it down too tight when put it back in place. What surprised me it that it didn't immediately affect the print, it could be 20 minutes in before the problem occurred, which I agree could imply heat related.
The O-Rings aren't very forgiving when it comes to pressure adjustments a quarter turn is a big difference when your "spring is only 2mm long.

I agree on the o rings. I dont blame SeeMeCnc for the stepper heat issue. I am running a different controller and a different stepper too ( I needed a 6 or more wire stepper). Come to think of it the only thing H1 is the actual roller/drive assembly and the new PEEK tube for a 3mm hot end (with a Makerbot MK6 hot end and H1 nozzle). I have a glass heated bed, I just havent installed it on my mill. The difference between removing the printed items from a heated or non heated bed is night and day. My prints were stuck so well I thought the 1/2" temepered glass was going to break. I finally had to wedge a razor blade under the print to lift it. No warping of the bottom or the corners.