Hobbed bolt eating plastic

I'm not sure if it's why i keep the springs too tight (but though, if i don't the filament keeps not really going down) or something else, but the bolt seems to 'eat' the plastic, which remains trapped in the small holes in it.
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The white piece there in the center is the plastic (the color is transparent).

Or maybe i have to tighten the spring even more? Even though I ran out of space with those.
I'm not sure to understand where i have the problem, I've even printed a whole piece and even using it, but now started doing this way.
I also suspect the extruder (it's one of the maker bots) could have a slighter thin hole than 3mm and plastic may find a hard way going in...

Or maybe i need a bolt with more precise holes, that don't eat plastic?

Sorry for the typo, meant the extruder is from maker gear's

It looks like your hobbed bold needs to be hobbed some more. It's too shallow. You probably need to go down to about 6.5 mm diameter or less.

Yes, Much deeper, see attached. Also pressure on the filiment is good. I haven't see issues with too much pressure.

Well I took that bolt from ebay that someone made it... dunno if I even have the equipment to make that.
Will see this week end going around shops.

I've understood the problem though, thanks.

I had a similar problem. Ended up my hot end temperature controller was driving the temps too high. So the ABS sort of carbonized inside the head. That made it nearly impossible to squeeze the filament through. Had to replace the head. It never worked the same after that. Point being, I kept thinking it was the hobbed bolt or the tension. It was neither.

I used a drill press with an X-Y table used to carefully feed the 3mm tap into the bolt. So you are correct in that it requires some equipment. I would expect poor result if you tried this with a hand drill. I broke the tap and had to chuck it up on the threads, so it is a bit tricky. In the end I wouldn't expect needing to ever replace a hobbed bolt. You may want to try buying one off one of the many 3D home printer sites.

Hi:

I had a similar problem, twice. The first time from bad gcode. Examine the gcode to see if the correct temperature for the extruder is being produced by skeinforge . Also check the host firmware settings to see if the correct temperature is being set there, as that is what you probably use to warm everything up before calling the gcode generated by skeinforge. Too cool and the hobbed bolt strips. That was the first problem I had. Even after this, if I fed too fast it still stripped . Then I read Adrian's comment about a coarse (non M3) hob for the bolt. For my first hobbed bolt I used M3, big mistake. Next I used 6-24. I did that and never had another problem.

j

I could see where a finer pitched hobbed bolt would cause problems. More teeth results in less bite per tooth for a given pressure. Less teeth results in more bite and more gap between the points for the material to not build. I'm not running a wade's style extruder with the bearing, plate and four springs. My design has no springs and is probably running at a much higher pressure. So I agree that a 6-24 thread would cause less issues with a standard extruder then a 3mm. Good point.