Bondtech Admits INDX 'Hardened' Nozzles Aren't Really Hardened

Bondtech's INDX nozzles, marketed as hardened since pre-orders opened in November 2025, ship at HRC 30-32. The number comes from Bondtech's own staff, in a Discord reply that puts typically marketed hardened nozzles at HRC 55-60. In a support email, founder Martin Bondéus confirmed the fully hardened version never made it through manufacturing: what shipped is surface-treated steel, and the word "hardened" is coming off the product pages. Prusa, which built the CORE One's multi-material story on the INDX, says the news reached it out of the blue and answers are coming early next week. So is an official statement from Bondtech, along with compensation for Founders Edition buyers.

How it came out: a support email, then Discord

The story surfaced through a support ticket, not an announcement. A Founders Edition owner who prints abrasives asked Bondtech about the nozzles he'd received, and the reply came from the founder himself on July 17. During development, Bondéus wrote, Bondtech evaluated a fully hardened steel version at about 60 HRC, but "the cutting tools simply did not withstand the process", so it shipped the nitrocarburised version instead. Put simply, that's a treatment that toughens the skin of the steel while the metal underneath stays much softer than a through-hardened nozzle.

Source: Bondtech support email, shared by u/KrishanuAR on r/prusa3d.

The Discord record turned out to be a little ahead of the email. Asked on July 15 whether all the nozzles were hardened steel, Bondtech's Olof answered, off duty: "Kinda little bit hardened. Semi." He added: "I wouldn't use them for regular abrasives printing. But we have something on the way for that. At a high price." Two days later his colleague Gustav gave the community the numbers, HRC 30-32 against the 55-60 that hardened nozzles usually measure. By that evening the screenshots were on Reddit, where the r/3Dprinting thread passed 600 upvotes in a day and the r/prusa3d thread filled with photos of boxes and invoices.

Source: Bondtech Discord, screenshot posted by u/jl88jl88 on r/3Dprinting.

What the marketing said: "zero fear of wear"

The advertised spec wasn't a stray line. From the November 2025 pre-order page onward, the INDX spec table read "Nozzle Properties: Hardened with CHT", and the product pages carried a paragraph Bondtech repeated across the Founders Edition, the Development Kit, and the standalone tool listings: "Crafted from hardened steel, these nozzles offer exceptional abrasive resistance, allowing you to print Carbon Fiber, Glass Fiber, and glow-in-the-dark filaments with zero fear of wear."

Source: bondtech.se product pages via the Internet Archive, posted by u/HallwayHomicide on r/3Dprinting.

Prusa's shop says the same thing in its own words. The INDX conversion kit page lists "Hardened nozzles by default handle any abrasive filament" in its comparison table, and its FAQ promises that "abrasive filaments (carbon fiber, glass fiber) work from day one". That wording has been on the page unchanged since orders opened in April.

Source: prusa3d.com conversion kit page, screenshot posted by u/theMondegrue on r/prusa3d.

The word followed the product into the box. Buyers in both Reddit threads posted retail boxes printed "Hardened" in every nozzle size, invoices with "Bondtech INDX Hardened Tool" as a paid line item, and packing slips listing the same word. One detail worth keeping straight: hardened wasn't a pricier variant. Every passive tool sells at the same price today, so what buyers paid for wasn't an upgrade, it was the description.

Source: Founders Edition delivery photo posted to the r/3Dprinting thread.

Source: order invoice shared by u/Angus_Luissen on r/prusa3d.

"Hardened" is leaving the product pages

The rewrite happened the same day the community found out. The spec table that read "Hardened with CHT" as recently as July 2 now reads "Steel with CHT". The tool formerly sold as the "CHT Hardened Tool" is now the "INDX Passive Tool Steel CHT", described as "constructed from steel", with the abrasives paragraph gone. A separate "Hardened Steel" tool page from June now returns a 404.

The sweep isn't finished. As of July 18, the Development Kit and Founders Edition pages still carry the full "zero fear of wear" paragraph, the renamed tool's web address still contains "cht-hardened-tool", and its search-listing description still calls it "Hardened Steel CHT". Bondéus addressed the edit directly in his email: "This is also why we removed the 'hardened' wording from the product page to avoid creating incorrect expectations."

Where Bondtech and Prusa stand

Bondtech hasn't published a statement yet. Beyond the founder's email, its position lives in Discord messages: Gustav wrote that the nozzles "should handle CF/GF okay" but "will not survive the most abrasive filaments", and that proper hardened nozzles will come later. On July 18, after what he called a good meeting, Olof told the Discord that "all founders will be compensated" and that official communication goes out early next week. Nothing about what the compensation is, and no timeline for a truly hardened nozzle; the email is direct about the latter: "I unfortunately cannot give you a reliable timeframe."

Prusa was caught out too. Its team account on Reddit posted that it is "looking into this and confirming with Bondtech", with little more expected before people are back in the office on Monday. On the Prusa forum, an admin added that the news came "out of the blue" for the staff running the INDX launch. Meanwhile its conversion kit page still advertises the hardened nozzles, and the first kits are due to leave the factory at the end of July.

If you bought one for carbon fiber

For occasional carbon-fiber or glass-fiber work, Bondtech's own guidance says you'll probably be fine. The founder's line is about duration: the shipped nozzles are "not intended for prolonged use with highly abrasive filaments". If abrasives are your daily bread, that's the problem: there is no INDX nozzle you can buy that Bondtech rates for them. And the nozzle isn't a generic part you can swap for a Diamondback. It's the induction-heated element itself, proprietary to the system, and Bondtech is the only source.

Bondtech's own framing is the honest way to plan around them: "See these nozzles as your 'standard' brass would be, but they last way longer than brass." Consumables, in other words, not lifetime parts. How fast they actually wear on glass-fiber nylon is the number nobody has yet.

Item	Price	Where
INDX Passive Tool Steel CHT (0.40 to 1.00 mm)	$55.35	bondtech.se
INDX Passive Tool 0.25 Precision / 0.4 Standard Flow	$55.35	bondtech.se
INDX Smart Toolhead	$479.70, in stock	bondtech.se
Prusa INDX 4-Tool Conversion Kit	$749 (669 EUR)	prusa3d.com, ships from late July
Prusa INDX 8-Tool Conversion Kit	$999 (899 EUR)	prusa3d.com

Bondtech shop prices exclude tax; Prusa kit prices include tariffs and VAT. Founders Edition invoices from the pre-order round show 30.46 EUR per extra 'Hardened Tool', so the shop price has moved since. Prices checked July 18, 2026.

What to watch next

Bondtech's official communication and the shape of the Founders Edition compensation are due in the week of July 20. Prusa has promised its own answer around the same time, and it has a more immediate call to make: its kit page still promises hardened nozzles, and the first conversion kits are scheduled to ship within two weeks. Further out sits the nozzle Olof teased, an actually hardened tool "at a high price". This page will be updated as each of those lands.

Frequently asked questions

How hard are the Bondtech INDX nozzles that shipped?+

HRC 30-32, per Bondtech staff on the company Discord on July 17, 2026. The same message puts typically marketed hardened nozzles at HRC 55-60. The shipped tools are nitrocarburised, a surface treatment, rather than through-hardened.

Can the Bondtech INDX print carbon fiber or glass fiber?+

Occasionally, yes: Bondtech staff say the shipped nozzles 'should handle CF/GF okay'. The founder's email draws the line at duration, calling them 'not intended for prolonged use with highly abrasive filaments', and there's no abrasive-rated INDX nozzle on sale or scheduled.

What did Bondtech advertise the INDX nozzles as?+

'Hardened with CHT' in the spec table since the November 2025 pre-order page, and 'crafted from hardened steel... with zero fear of wear' for carbon and glass fiber on the product pages. The boxes, invoices, and packing slips buyers received all say 'Hardened' too.

Will Bondtech compensate Founders Edition buyers?+

Bondtech's Olof said on Discord on July 18, 2026 that 'all founders will be compensated', with official communication promised for the week of July 20. What form it takes isn't announced; nothing formal has been published yet.

How much do INDX nozzles cost?+

$55.35 each excluding tax on bondtech.se as of July 18, 2026, in sizes from 0.25 to 1.0 mm. They're proprietary to the INDX system, so Bondtech is the only source; standard V6-style nozzles don't fit because the INDX nozzle is the induction-heated element itself.

Does this affect the Prusa INDX conversion kit?+

The $749 and $999 kits (669 and 899 EUR, taxes included) start shipping from late July 2026, and Prusa's page still lists hardened nozzles as standard. Prusa says it's confirming details with Bondtech and expects to say more early in the week of July 20.

What is nitrocarburising?+

A surface treatment that hardens the outer skin of the steel while the core stays around HRC 30-32. It wears better than untreated steel, which is why Bondtech compares the shipped nozzles to long-lasting brass, but it's well short of the HRC 55-60 of a through-hardened nozzle.

Sources & methodology

• r/prusa3d thread (July 17, 2026) with the founder's support email and the product-page screenshots
• r/3Dprinting thread (July 17, 2026) with the Discord screenshots, box photos, and invoices
• Prusa forum: 'Bondtech nozzle hardening debacle', including the compensation message quoted from Discord and the Prusa admin reply
• Bondtech INDX pages, live: the reworded tool listing, spec table, Development Kit and Founders Edition pages
• Wayback Machine captures of bondtech.se: the pre-order spec (Nov 29, 2025), 'Hardened with CHT' still live (Jul 2, 2026), the Development Kit wording (Jul 16, 2026), plus an archive.is capture of the tool page
• Prusa INDX conversion kit page, live, with the April 24, 2026 Wayback capture showing identical nozzle claims
• Prusa blog: the INDX announcement (Nov 19, 2025), orders opening (Apr 23, 2026), and the State of INDX update (Jul 3, 2026)
• Buyer-posted invoices, packing slips, and box photos in both threads (u/Angus_Luissen, u/jbohbot, u/x4rb1t, u/Gb160, u/yawaworht1129)
• Images: Bondtech official product media