Converting old TAZ 4 extruder to flexystruder

I just received my new hexagon extruder and want to convert my old one to a flexystruder. I’m now trying to source all the non-printed parts needed for the conversion that I can’t scavenge off the old extruder. Has anyone done this before and have extra bits you want to sell off (PTFE tubing, heatset inserts, etc)? I’m worried that I’ll spend a small fortune trying to hit the minimum quanities needed to buy this stuff online.

I’m now ordering everything from McMaster-Carr. I will have plenty of extra parts if anyone else is interested in doing the upgrade yourselves. I’m converting the TAZ 4.1 Extruder (TAZ-BOM-Holly_500order.ods) to a Flexystruder 1.1 (Flexystruder-V1.1-BOM.ods). Total cost of all the required parts (assuming there aren’t any surprises) came out to about $50.

According to the BOM’s, the differences are:
HD-BT0010 - M4 x 20 Bolt, SHCS Black-Oxide (required: 2, min order: 100)
HD-BT0049 - M5 x 14 Bolt, SHCS Black_Oxide (required: 1, min order: 10)
*HD-MS0055 - Thumb Screw Knob for M5 SHCS, Black (required: 1, min order: 10) (combines with HD-BT0049)
HD-MS0060 - M5-.8 11mm Heatset Insert (required: 1, min order: 25)
HD-TB0006 - .25"ODx.125"ID PTFE tube (~2.5") (required: 4", min order: 12")

PP-GP0096 - Extruder mount, TAZ (Printed)
------------- - Flexystruder Body V1.1 (Printed)

So it looks like other than the PTFE tube I will have enough for several people. Let me know if you need anything and I’ll send it out when I can. I’ll just ask you to pay for the shipping which should be minimal.

I would be very interested in doing that upgrade as well, I was filling up my cart on McMaster-Carr to that very same thing.

Well I did the conversion last night. It is surprisingly easy as long as you have access to a drill press. The good news is you don’t need as much stuff as I thought. The mounting bracket is identical and the bolts used to attach the hot end can be reused. Also the smaller heatset inserts are not needed… I’m not sure why I thought they were.

Anyway, I’ll write up some directions later when I have some time, but it really isn’t needed. It is as simple as tearing down the old extruder and reassembling it as a flexy. One tricky bit (no pun intended) was not having the metric drill bits. I cheated and used 9/64 (3.6mm), 1/4 (6.4mm), and 5/16 (7.9mm) instead of 3.5mm, 6.5mm, and 8mm respectively. If I thought about it when I ordered my parts I would have much rather had the metric bits.

My other slip up was not putting the heatset insert in the flexystruder bracket before putting in the PTFE tube. With the tube already in place I had to be careful with my soldering station to not poke the tube while installing it. I managed ok, but would have rather done it first and not have to stress over it.

Here is where my happy story turns ugly…

:exclamation: Under absolutely no circumstances should you hook up your new Flexystruder without updating your firmware!!! :exclamation:

I was so excited and proud of myself for doing a good job in the conversion that I jumped in and powered it up to see if it worked. At first it did, but I could see the heating resistor glowing red hot and it eventually quietly died. Only afterwards do I realize that there are probably different power requirements between the budaschnozzle and the hexagon hot ends :frowning:. After this resistor failure I tried to see if the extruder would spin and it would not. Hopefully the stepping motor didn’t die as well and will work once I change the firmware.

The good news for you is that I do have all the parts you will need for the conversion. PM me your address and I’ll send them along to you. If you don’t have access to a drill press and would like me to print you out the flexy bracket and set it up, let me know. The parts are free if you want them, but my printing and assembly time will cost you beer money :slight_smile:

So you flashed the printer to work with the new V2 print head and you need to switch back to work with the old Budaschnozzle? Just wanting to be sure I’m on the same page as I’m planning on doing the same thing to my Taz.


Yes, exactly! Actually AO has an updated firmware for TAZ 5 owners wanting to use the Flexystruder, but I don’t know if this works for the Flexystruder with the Budaschnozzle or if it is only for the new Flexystruder that will use the Hexagon hot end.

Check out the Flexystruder “Links” section for more info:

EDIT: On closer look, it says TAZ 4 can use it without a firmware update, so this is definitely for the Budaschnozzle.

Just a quick update… The reason it wouldn’t turn the extruder gears is because the marlin firmware is preventing cold extrusion. So my only issue is the heating resistor which is easily ordered from DigiKey in small quantities.

Looking at the Flexy Struder page I guess I’ll need to order a .5mm nozzle as well…


According to the BOM for the Flexystruder v1.1, it has a .35mm nozzle. I would stick with the existing hot end at least until you see how it performs. If it starts making a mess with the smaller nozzle, you could always put the fan back on it with the upgraded fan shroud that sends air to the heatsink.

I was just thinking we may want to use some PTFE tape too to help prevent any pooling/oozing around the heater block. May as well look at this while tearing everything apart:

(more detailed instructions)

I did something something like this with my old flexy and a new hex printhead. No drilling, machining, etc. Just a little tinkering and rebuilding.

Thanks dutchhome! First semiflex print underway right now… assembly was pretty easy and I remembered to flash the firmware!

So far, this is looking OK:

  • 230º extruder / 0º bed
  • 30mm/s base speed
  • 2mm retraction distance
  • PET surface (my PEI is removable)

Nice! I still haven’t been able to try mine yet :frowning:

I finally received the small crimp pieces to attach the new heating resistor just to find out my wife threw away the old insulating tubes… Grr…

It seems like I’ll eventually have enough extra parts to start my own production run :slight_smile:

Yeah I converted a AO-100 extruder into a flexy about 6 months ago for this nice guy I know that works for Fenner drives and did some testing on this filament they were trying out! :smiley: Had to use what is available at the time, and did not have access to a unused Taz or Mini! :cry:

Just wish I could get my prints to come out even half as good as his do!

I’ve got the later budaschnozzle and it doesn’t seem to have any problem printing PLA so I don’t think I’ll have a problem with leaking at the top of the hot end. On the flexible filament profile they point to a .5mm nozzle here:
I saw the Taz 5 firmware update for use with the Flexy struder and am also wondering if I use this for my TAZ 4 with the Hexagon hot end I can use either extruder with one firmware. We’ll have to wait and see.


I believe the TAZ 5 Flexy firmware is for the Budaschnozzle. This is why the Flexystruder page says that the firmware isn’t needed on the TAZ 4. Since the TAZ 5 has the hexagon hotend it has a different power profile and thus requires a firmware update. I learned this the hard way… I’m still waiting to try my upgraded hotend after trying to use the Flexy conversion with the TAZ 5 firmware (not the TAZ 5 Flexy firmware).

I can confirm dutchhome’s last comment. If you open up the configuration.h file in the flexy/taz 5 firmware, it is noted clearly that the values in it are for the budaschnozzle extruder and not the hexagon.

Just to be totally clear – if you have a taz 4 with an upgraded hex toolhead, you need to switch your firmware to the flexy/taz5 firmware to use the flexystruder!

Stupid question, Are the printed parts hard to print? Can they be PLA, (do any of them need to be flexible?)…

I am pretty excited by this project. Once I get the new extruder I would love to convert it as well. If things quiet down, I might be doing this sometime in April. I will try to see if you have any spare parts by then.

You only need to print one part - the Flexystruder body. The other parts (gears, bracket, etc) can be salvaged from the old extruder. My guess is that it should be printed with ABS. If you want, I’ll print out the body for you (choose between black, white, red, and blue) and install the PTFE tube and heatset insert and send it all to you. Then all you need to do is tear down the old extruder and rebuild it with the Flexy body.

A thought…

Would it work to use a new heater resistor (from the new hexagon hot end) in the old budaschnozzle, in order to avoid flashing the firmware every time I change struder? If so, what’s the actual part number? Can’t find anything in the developer section on the new hot end…

Any Lulzbot staff out there that could comment on this?