Hi everyone! Could anybody please tell me if these hobbed bolts work with 1.75

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(Mark Moissette (ckaos)) #1

Hi everyone!
Could anybody please tell me if these hobbed bolts work with 1.75 mm filament ?

I have contacted Airwolf, and they only tried it with 3mm filament, so any experience running 1.75 mm filament with these would be great!
Thanks in advance !

(Whosawhatsis) #2

I strongly recommend against using a geared extruder for 1.75, but other than that it should work fine. One that is grooved particularly deeply might be a problem, but that does not appear to be the case in this picture.

(Miguel Sánchez) #3

@Whosa_whatsis why? I cannot reach the same speeds with direct drive I can with a geared extruder (5:1).

(Whosawhatsis) #4

@Miguel_Sanchez Then you’re doing something wrong. Too weak a stepper maybe? A direct drive extruder should be able to push 1.75 much faster than you would ever want it to, while a geared extruder will max out its step rate at too low a speed while all that extra torque goes to waste.

Are you sure you were actually moving the filament faster with the geared extruder, and not just putting in a higher number (which was being limited by the maximum step rate) and not getting clicking, not because of the increase in torque but because it wasn’t actually moving as fast as you told it to?

(Miguel Sánchez) #5

@Whosa_whatsis I asked because right now I am printing at 60% of gcode speed for my stepper to not lose steps. Same file will print happily at 150% when using a Greg’s geared stepper with the same hotend. Stepper is at 1.3A (motor is 58 oz-in 1.3A nominal). Power supply is 12V though. If I am doing something wrong, I am more than willing to fix it :slight_smile:

Infill speed is 90mm/s for 0.3mm layers and my nozzle is 0.5mm. If I am not reducing the speed I get many missed steps and intermittent infill.

You can have a look at my setup in the main picture of this: http://www.thingiverse.com/thing:152210

(Miguel Sánchez) #6

@Mark_Moissette_ckaos Sorry Mark for hijacking the the thread :slight_smile: Hobbed bolt looks good but the distance from the edge of bolt’s head to the groove may be a bit too much (nothing that cannot be cured with some extra washers though). You can check that out with your extruder’s STLs.

(Whosawhatsis) #7

It’s too damn late here for me to do all the math right now (including collecting the additional bits of information like steps/mm settings that I would need for the calculations), but at first glance, the numbers you threw out seem consistent with all of the causes I mentioned.

(Mark Moissette (ckaos)) #8

@Whosa_whatsis thanks ! Yes, this hobbed bolt does not seem deeply cut enough to cause issues ( I was surprised but even managed some relatively good results with an http://arcol.hu hobbed bolt I had available, which has rather deep cuts).
A direct drive extruder is planned down the line, but for now the current geared ones will have to do.

@Miguel_Sanchez no problem at all ! Any extra information/experience is good to have !
I’ll need to recjeck the distance to the groove, but as you say, a few washers should do the trick :wink:

(Whosawhatsis) #9

I haven’t used extruders with printed gears in some time, but as I remember, the washers aren’t really necessary and just add noise. Herringbone gears won’t slip axially at all, but even regular spur gears shouldn’t need them because the filament in the groove prevents axial slip, and letting it have play in that direction allows the groove to self-align to the filament.

(Miguel Sánchez) #10

Absolutely, if using herringbone gears they will self-align. But still one washer is recommended for the side opposite to the gears before the locking nut.

(Whosawhatsis) #11

The last few months that I was using a wade’s, I didn’t even bother with the nut. Makes cleaning the teeth much easier if you can just pull the thing out once the filament is removed.

(Miguel Sánchez) #12

I could not do that if using herringbone gears. But I do this regularly with my compact extruder.