Honeywell/Honeywell North® to 40MM NATO (RD40x1/7) Thread Adapter

thingiverse

The provided text appears to be a README file associated with a 3D printing project for creating adapters for Honeywell/Honeywell North respirators. The adapter is designed to allow the use of NATO standard 40mm filters on these respirators, which are commonly used in medical settings. Here's a summary of the key points from the text: **Gen. 2 and Gen. 3 Changes** * Gen. 2 changes include: + Redone chamber from underside OD to wrench flats to reduce printing overhang supports + Added engraved markings on exterior periphery to ID adapter * Gen. 3 changes include: + Completely removed printing overhang support from wrenching ears + Updated chamfers accordingly + Added a new version for M25.889x1.554 (a 1% reduction in the respirator side threaded interface) **Risks and Disclaimers** * The design is not officially sanctioned by Honeywell/Honeywell North, and users assume all risks when using these adapters. * There may be discrepancies between the designed threads and actual respirator threads due to tolerance stack-up or other factors. * Users are advised to perform a negative pressure test to ensure proper seal and function. **Usage Instructions** * Use proper gaskets or O-rings at both ends of the adapter (filter side and respirator side) to ensure a proper seal. * Perform a negative pressure test by donning the respirator, adjusting straps, covering inhalation ports, and inhaling deeply to check for air leaks. **3D Printing Considerations** * The 3D printing materials used may degrade when exposed to chemicals, heat, or UV/sunlight. Users are advised to apply a thin layer of polyurethane clear coat on all exterior surfaces to improve durability. * Hot nozzle passes and infill optimization are recommended to reduce surface porosity. **Credits** The project credits Clownrock95 for providing the original Honeywell/Honeywell North adapters and spec, as well as erniepike's trial and error process in discerning better fitment threads.