Q about Taz5 Dual Extruder V2 Levelling Screw

I recently installed my dual extruder v2, and I’m dialing it in and getting it to work well. I’ve used cura some, and Simplify3D.

I have a question about the levelling screw, which is pictured well in the OHAI assembly instructions, step 21. I’ve added this picture here, plus some markings pointing to where I’m asking about.

I want to add a knurled knob to the cap of the levelling screw, because it’s very inconvenient to use a hex wrench, and I’m pretty sure I can get enough force with a knob. (When I’m only using 1 extruder, the rear, I like to adjust the front extruder high out of the way.)

There’s a nut on the end of the levelling screw which I first thought was a lock nut that one would tighten after adjusting the levelling screw. But on my system, this nut is ‘fused’ or ‘stuck’ onto the threads. Tight enough that a tug on a small wrench wouldn’t loosen. If it’s supposed to be ‘stuck’ on the threads, I don’t want to break it.

So is this just really a lock nut, or somehow stuck on to keep the screw captive?


I am not positive, but I suspect that nut is “glued” on (red thread locker) to act as a fulcrum. The up and down movement is controlled by threaded insert in the flex plate.

I’d say: “Go ahead and try the knurled knob.” However, I would try to attached the knurled knob without disassembling the adjustment screw.

Dis claimer, dat claimer, any ol’ claimer: My Javelin is home built and Luzbot may have been WAY more intelligent in fabricating their production version than I was. :laughing:

Adding a knurled knob would be nice for finger adjustments… I’ve been looking for one on thingiverse that would just friction fit onto the M4 socket head. I haven’t come across anything that I like, so it’ll probably need to be designed… a dual extrusion print with contrasting “dial” markers might be nice.

That nut is locked in place to allow the M4 screw to rotate freely in the aluminum plate. If it wasn’t there I suspect the top plate with the insert would just “push” the screw out of the aluminum plate. Geburges described the functionality pretty well, and I suspect he’s right about the loctite… or the screw could be tightened against the shoulder of the screw.

Looking at the design, they should have screwed the M4 screw in from the top. Leave the aluminum plate solid. Which would allow the screw to “press” into the plate while using the threaded inserts for adjusting the deflection.

They make press fit M4 thumbscrew head plastic bits. I know where to buy them locally, but they seem elusive online.

Yeah, I’ve seen places that source the snap-on thumbscrews.

I modified my bed levelling screw thumbscrews to fit the dual extruder leveling screw. I’ll post to thingiverse and the thread once I work out the kinks.

EDIT: Okay. Here’s the thumbscrew cap for the leveling screw (M5). Single extrusion or dual extrusion version. If its not tight enough, print with an increased flow rate or multiplier.
TAZ5 - M5 Thumbcap_DualColor1.stl (78 KB)
TAZ5 - M5 Thumbcap_DualColor0.stl (219 KB)
TAZ5 - M5 Thumbcap_SingleColor.stl (287 KB)

At the Open house Friday I talked to the R&D guys about the availability of the OHAI guide for the dual hotend. He thinks it may still be restricted access, but I am looking for it still this weekend. So if anyone has seen it, send me a link for it. Please! :laughing: Otherwise I will continue to work on getting him to put it up for people to use/link to.

It would show about the screw and stuff.

There is an OHAI guide to calibrate the extruder. Not for the assembly and dissassembly, though. Which is what you’re looking for.

Since they won’t offer this as a “kit”, I doubt they’ll put an assembly / disassembly guide together unless there is some serious maintenance issue that crops up. I’ll have to check on the V1 dual extruder for this type of guide, but with recent business changes I wouldn’t hold my breath. :slight_smile:

Being open source they tend to make available their guides that they use. I know they had one for the V1 flexystruder, but I have not looked for that for several years now, so I am not sure they even have one any more. :blush: The V2 I did not even look for since I have built a number of V1 now.

As for the V1 dual I seem to remember one when I built the Dually Cooly I played with last year.

They are pretty cool people there and very helpful when asked!

This is the O.P. Thanks to all who’ve replied, and especially kcchen_00 for your model.

I ended up finding an M3 knurled cap and printed it at 160% to get it to fit the levelling screw. As it wasn’t such a good press-fit, and it’s not nice at all to try to press with any real force on an extruder installed in a system, I used a drop of glue to hold it on.

But I like the 2-color version kcchen_00, and I’ll try that once I get 2-color working on my system.

That’s an idea… I’m going to shrink my thumbcap down 40% to replace my Z-endstop. :smiley: That’s where the extra color might help with calibrating.

Here’s a picture of the dual color thumbscrew cap.

Regarding the Open Source movement. I applaud LB for sharing their designs, but finding more and more that they are becoming more proprietary. An example, where else can you source the small heatsink blower for the hexagon? While they have build instructions for the Kittaz, there are no build instructions for the pre-built TAZ 5 or Mini. Hence, I don’t believe they will have build instructions for the pre-built dual v2… for the mechanically inclined its not hard to figure out what goes where if building from scratch. :slight_smile:

Quick update to the dual extrusion M5 Thumbscrew Cap for anyone interested. I added the center allen hex for better grip on the screw. Its a bit finicky to put on screw, I found using a normal allen wrench to visualize how to line up the thumbscew helps.
M5 Thumbscrew.v7.stl (276 KB)
M5 Thumbscrew Color2.v7.stl (78 KB)
M5 Thumbscrew Color1.v7.stl (208 KB)

I got my baseplates and just started building mine. I need to find some additional hexagon barrels somewhere around here though heh.
I’m almost thinking I can get a duct down around the two front holes to make a 40mm fan driven extruder barrel cooling duct thing, but i’m struggling to think of a good place to put the intake fan(s) that won’t interfere with the existing filliament cooling fans. I’m almost thinking of moving those back and in some, which will weaken the frame, or dropping them down 2 washers worth, and putting a cap over the unobstructed intake for them and running the fan and duct for the barrel coolers there, allowing the filliament coolers to draw air from the sides. Not sure yet.

I think I saw some “spare” hexagon parts at IT works…

The heatsink fans will be challenging. I’d have to take a look at the dual extruder again… but it may be possible to design a single duct that encompasses both heatsinks. Put it on the front of the toolhead.

If you’re building from scratch, maybe adapt the plate for an E3D V6… Should be a quick change to the plate thickness and possibly the openeing for the hotend.