Re: E3D v5 All Metal w/Direct Pinch skipping/clicking proble BD that does not look quite as bad, i do see some roughness from the drill bit that might effect the PLAs adhesion a bit (maybe just polish it with some ss polish?), but i don't see any actual hard ledges on yours, at least not at that angle/perspective. The microscope that i use is the f-cam digital microscope Model # MAN1011 Its not a "lab" microscope but more of a machinists best friend for looking at small details. i think its a discontinued model as it was priced at ~$60 way back when, but amazon seems to have one or two copies available at a "you cant get this anymore" price of $120 http://www.amazon.com/QVS-2-Megapixel-D ... microscope I suspect this one,. http://www.amazon.com/Celestron-Deluxe- ... microscope or this one http://www.amazon.com/Plugable-Digital- ... microscope to be fairly similar. though i do really like how you can stick things into the lens shroud on the one i have. I am not 100% sure you can do that with the others. best way i have found so far to set it up for looking down a filament barrel is,. set it up with the microscope on its holder, and the barrel held by a "helping hands roach clip" then stick the barrel all the way inside the microscope,. the LEDS on the microscope will no longer be helpfull,. so then,... point the end of the barrel at your monitor, and open a blank text document (for its bright white background) to shine a soft light down the barrel. then just adjust focus to slide down the barrel. e3D if this ends up being the actual issue,. you could ad this inspection of the inner barrel as part of your quality control practices,. it only takes about 10-20 seconds to inspect the length of a single barrel this way. and if you made a sturdier rig to hold things firmer, i suspect you could shave a few more seconds off that.