M4 Hinged Extruder, Reinforced Guidler
by 4ndy, published
When I first printed Greg's Hinged Accessible extruder, I had to hack out the top captive nut holes that idler bolts went through since they were under-sized in one direction, then ended up accidentally over-sizing the holes with my multitool's chisel, so I used M4 nuts and bolts instead. (I wasn't even sure at the time if it was meant to be M3 or M4 fitting since the bolt holes were loose)
I since realised that it's much easier to get enough idler pressure on the filament while using the same stiff springs that support my printbed, which barely fit in the area of a form-A M4 washer, while suggested pen springs on M3 bolts are nearly impossible to tighten enough and it's hard to find M3 bolts long enough in the first place.
So, I've re-designed both the extruder and idler with holes that should be large enough to not need reaming for M4 fittings, while keeping over my double-option hot-end mounting slots from a design that I produced before finding the default STL-import options in SolidWorks that had prevented me editing things from STL before.
* Motor mounting bolt-holes have 2mm added depth, because I've always found it extremely difficult to fit a motor to this bracket using M3x10mm bolts and single washers after removing the support material, since they barely reach the other side; the M3x20's that I have are too long, and who the hell gets 15mm bolts?
* A slot has been cut out of the bottom at the motor-bracket end of the extruder body, which I have had to do with a pen-knife before since otherwise it wouldn't fit on a Mendel x-carriage due to collision with a bolt head.
* I reinforced a stress-concentrating corner just above the hinge point on the idler part, since I've had a couple of those break on me there. I also added a small thumb-handle to the idler, as I've seen a larger one elsewhere.
The J-Head mounting body is based upon direct measurements of a Mk.IV hot-end using calipers. It fits better than any I've found yet.
* Enlarged the guidler hinge captive nut hole, it is actually usable now without instantly breaking the hinge, yay!
* Reinforced one side of the guidler's filament guide, which previously broke on me and caused a print to fail.
* Also added M3 versions.
Recent Commentsview all
The cable-tie slot was inherited from Tom's design, but thanks. :) I like that slot since it stops my hot-end wire connections getting shaken around - I've had those connections break through months of fatigue before.
I dropped your stl into Sketchup and pulled the base down by 4mm, in a simple rectangle shape. It was a crude way of raising the height but it worked. 4mm was enough to give the clearance from the deck I needed to fit the strong herringbone gear set from the 'greg's reloaded' extruder.
Thanks for the explanation of the v-groove. I may make user of it now I know what it's for! Although, I have my hobbed bolt fitted with a single nut and spring (a la Nophead) to allow the bolt to be easily removed for cleaning. Good to have the groove for visual inspection of the hobbing though.
The thickening of the motor bracket in your design is great. I've found that bracket a bit weak in previous designs but it now feels very solid, especially with the motor attached.
Finally, your positioning of the bolt holes to hold the J-head is perfect, and the little slot to take a cable tie t
o hold the hotend wires is a nice touch! Great work!
I first saw a notch added behind the filament path in thing:16928, and since then GregFrost has made a similar alteration in his latest extruder model. Its purpose is to allow you to clean out individual teeth on a hobbed bolt without removing it from the extruder.
I saw that a rounded cut-out could leave a nasty overhang (out into space where it can't bridge to anything) under the second idler-bolt nut-holder, where the print isn't very thick already, so figuring that a 45-degree slope could reliably give a decent slot to get a smalll screwdriver down without sacrificing print quality and hence strength, I used that.
How much extra height does the base need to support herringbone gears (i.e. what's the increase in radius)? It shouldn't take long to change the part if you can tell me, but if it's not very much, you could even consider putting a couple of layers of cardboard (with holes in to fit mounting bolts
through) between your extruder and x-carriage as a sort of washer/gasket, which could both raise the extruder body up and absorb some vibration if they are clamped in there tightly.
Thanks for the feedback. :)
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