Prusa CORE One INDX Kits Hit by 'Nozzlegate': Bondtech Nozzles Fall Short

What happened

Prusa Research has paused shipments of its INDX toolchanger conversion kits for the CORE One after Bondtech, the Swedish company that makes the INDX system, admitted its nozzles do not meet the hardened steel specification advertised to buyers.

The issue surfaced when a Reddit user posted a support email from Bondtech founder Martin Bondeus. In that email, Bondeus confirmed that "during production, we encountered manufacturing challenges that prevented us from machining that material reliably - the cutting tools simply did not withstand the process." Rather than delay the product, Bondtech chose to ship a nitrocarburized steel nozzle as a substitute.

Nitrocarburized steel has a hardened outer shell. It is tougher than standard brass, but it is not the same as fully hardened steel. Bondtech's own testing puts the shipped nozzles at 30-32 on the Rockwell C scale. True hardened steel typically lands at 55-60 HRC. The gap matters when you start running abrasive filaments.

Prusa's response

Prusa Research posted an update on Reddit stating that Bondtech had not yet finalized a compensation plan for affected customers. The company decided to hold INDX kit shipments until mid-August rather than send out a product with an unresolved specification question. Prusa also offered customers the option to cancel their orders. As a goodwill gesture, INDX conversion kits will include extra hardware at no charge once shipping resumes.

Prusa's own engineers tested the INDX nozzles and found little wear after five kilograms of carbon-fiber PETG. The protective coating began to fail after roughly 100 grams of super-abrasive Ultraglow filament. For users who stick to standard materials, the nozzles work fine. The problem is the marketing language that preceded delivery.

The community reaction

One Founders Edition buyer responded by building an entire protest website called Nozzlegate.com. The site lays out the customer grievances and offers guidance on how to file complaints with consumer protection bodies. The owner, who goes by the handle Daddie0, told Tom's Hardware he built the site in a single session after becoming frustrated with the lack of communication from Bondtech.

Bondtech has stated publicly that a solution is not ready and that producing truly hardened INDX nozzles could take months. The INDX uses a bespoke induction-heated nozzle with no off-the-shelf replacement available, so owners cannot simply swap in a different nozzle while they wait. Bondtech is asking customers to avoid returning the kits and to stick with non-abrasive materials until a replacement plan is confirmed.

The bigger picture

The INDX is a collaboration between Prusa Research and Bondtech. The first wave of Founders Edition kits was a limited 1,000-unit run aimed at early adopters who pre-ordered months in advance. Installing the kit requires dismantling an existing CORE One, removing the Nextruder hot end, fitting the INDX carriage, and mounting a rack for eight toolheads - a full weekend project for most owners.

The core issue here is not that the nozzles are bad. For most everyday materials they will perform adequately. The issue is the gap between what was marketed and what was delivered. Bondtech has not disputed that the "hardened steel" language was incorrect. What remains unclear is what, if anything, buyers will receive by way of remediation.