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Documenting the Mk I NutjobSaturday, May 02. 2009Trackbacks
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The title made me giggle.
By the way, does it try and twist the filament much when you extrude?
Me, too. I thought about naming it the nutty buddy, the nickname for an old candy bar from my childhood. In the 21st century, the name, however, has taken up an entirely new role which you can see here. http://www.nuttybuddy.com/player.html It was late at night and I wasn't quite ready for this cockeyed a reference. BTW, the filament twists about as much as it does in an old Mk II extruder. I've thought about using a pair of counterrotating left and right hand nuts to cancel out the twisting. For now, however, I'm going to see if this design has promise before I try to complexify the situation with left hand nuts, which have to be special ordered.
What keeps the gear with the nut in it from moving all over the place? I cannot see any constraints.
Look again at the closeup of the filament guide, and the gear with the nut - the nut is twice as deep as the gear, and extends down and around the filament guide, providing an axle.
I've included an extra picture of the bottom side of the embedded nut gear so that you can see the shaft.
A rep-rapped gear could easily have a plastic axle top and bottom to take the horizontal stress. It would have to be bigger than the nut, but would stop it moving and hold it in place.
Nice work, Forrest
I milled an axle on the bottom side of the embedded nut gear and let the nut surface but up against the top level plate housing as a thrust bearing.
Forrest,
Thanks for that, I think I understand it now.
A couple of clarifications: I assume the nut is about twice as thick as the gear, so it descends into the large hole in the white plate and acts as a bearing?
The filament guide looks like it should ideally be taller. Is that just limited by your stock material?
1) The nut is, indeed, about twice as thick as the gear. 2) The filament guide could be higher, but as you have correctly deduced, I was limited both by the thickness of my stock material and the maximum cutting depth of my 0.05 inch end mill.
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