Holes in parimeter of print

I am running with abs and i seam to be getting small gaps in the profile of my parts, i am thinking that it is the extrude unable to push enough material through the head and chewing the material. Are there any other thoughts,

At the moment i am running with an M4 hobbed bar but going to make a bare with M5 teeth to see if that can grip a little better.

I am currently running at 240C

I believe the first machines were made with M3, which is what I use. I've seen a trend go to M4 for some time. I tought I read that folks were having issues with the M3 stripping out. I think the issue wasn't in the pitch, but lack of pinch force. However you can easily see when its stripping out which happens as a result of some issue. A good extruder shouldn't strip out in normal operation.

So is the M4 stripping out? Do you have enough pinch force?

I have made an M5 bolt not and that seams to work really well before my lining failed and caused a jam.

The M4 was chewing the material up but the M5 really grabs the material.

Good. Sound like M5 is a better way to go.
So you think the filiment stripped on the M4 bolt and caused the lining to fail?
The nozzle of the extruder will jam up if any PTFE tears away.
Can you simply clean out the nozzle tip? Remove it, heat it and try to clean the material out thru the back?

When I started, I made my own hobbed bolt, and it worked okay. But it couldn't provide the gripping power I always needed and they weren't always perfectly round, although you couldn't tell just by looking at it. I think my printer has a hive76 m8 bolt now that I bought from ultimachine.com. [ultimachine.com]

It just works a lot more consistent then the hobbed bolts I was making. They have a higher tolerance than what I would do with a dremel. Now if the filament gets jammed, the printer won't stop, it will pull itself over trying to get more filament. It really grips hard. For $10 I think buying a hobbed bolt is worth it. I definitely spent more in plastic trying to get my hobbed bolts to work than I should have.

It is not a problem for me as I have a Cnc mill and lathe. The m5 is working perfectly with the new hot end that I machined.