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

This prototype design for a Honeywell/Honeywell North® respirator thread to 40MM NATO (RD40x1/7/DIN) gas mask thread, as requested by flipty. Designed to help cross compatibility of commercial off the shelf (COTS) filters with other manufacturer’s respirators, during this PPE shortage, should be compatible with any RD40x1/7 filter canisters.

If you do not have access to 40MM (RD40x1/7) filters, you can use the following adapters to step down to COTS filter cartridges from these companies below:

40 MM NATO to 3M™ Filter Adapter
https://www.thingiverse.com/thing:4245358

40MM NATO to Scott® 742 Series Filter Adapter
https://www.thingiverse.com/thing:4347531

40 MM NATO to MSA® Bayonet Filter Adapter
https://www.thingiverse.com/thing:4265715

40MM NATO to MSA® Comfo Classic Filter Adapter
https://www.thingiverse.com/thing:4267676

40MM NATO to Honeywell/Honeywell North® Filter Adapter
https://www.thingiverse.com/thing:4268775

40MM NATO to Honeywell Sperian® Filter Adapter
https://www.thingiverse.com/thing:4297348

40MM NATO to Honeywell Safety Sperian® /Survivair™ ValuAir® (Bayonet) Filter Adapter
https://www.thingiverse.com/thing:4345345

40MM NATO to AOSafety® Threaded Filter Adapter
https://www.thingiverse.com/thing:4273365

40 MM NATO to AOSafety® R5700 8051 Bayonet Filter Adapter
https://www.thingiverse.com/thing:4265538

40MM NATO to Portwest® Bayonet Filter Adapter
https://www.thingiverse.com/thing:4273464

40MM NATO to Moldex® 7000/9000 Series EasyLock® Bayonet Filter Adapter
https://www.thingiverse.com/thing:4275446

40MM NATO to Secura BC Bayonet Filter Adapter
https://www.thingiverse.com/thing:4294187

40MM NATO to JSP® Force™8 Filter Adapter
https://www.thingiverse.com/thing:4294203

40MM NATO to Delta Plus M3000 Mars Series Filter Adapter
https://www.thingiverse.com/thing:4311197

40MM NATO to Delta Plus M6000 Jupiter Series Filter Adapter
https://www.thingiverse.com/thing:4311200

40MM NATO TO GOST 8762-75 Threaded Filter Adapter
https://www.thingiverse.com/thing:4321450

40MM NATO to Draeger X-plore® Filter (3000/5000 Series) Adapter
https://www.thingiverse.com/thing:4329276

40MM NATO to ENHA Rockman 7300 Series Filter Adapter
https://www.thingiverse.com/thing:4329610

40MM NATO to Sundstrom SR Series Filter Adapter
https://www.thingiverse.com/thing:4338105

40MM NATO to Milla EURMASK® ETNA (Bayonet) Series Filter Adapter
https://www.thingiverse.com/thing:4342320

40MM NATO to Milla EURMASK® (Uno/New) Series Threaded Filter Adapter
https://www.thingiverse.com/thing:4342343

Alternatively, if you cannot source COTS filters, search thingiverse, there are a number of other DIY filter cartridge designs to mate to other major manufacturer, 3M/MSA/etc. respirator's attachment system.

Part Description:

HONEYWELLNORTH TO_40MM_NATO_ADAPTER__ M27X1.5_GEN1.stl
Female threads designed based off male M27x1.5 thread for Honeywell/Honeywelll North ® respirators, as reported by Clownrock95:
https://www.thingiverse.com/thing:4252141/files

HONEYWELL_NORTH_TO_40MM_NATO_ADAPTER__M26X1.57_GEN1.stl
Female threads designed based off male ~M26x1.57 thread for Honeywell/Honeywelll North ® respirators, as reported by erniepike:
https://www.thingiverse.com/thing:4252141/files

HONEYWELL_NORTH_TO_40MM_NATO_ADAPTER_M26X1.57_GEN2.stl
HONEYWELL_NORTH_TO_40MM_NATO_ADAPTER_M27X1.5_GEN2.stl
Gen. 2 features the following changes: (1) redone chamber from underside OD to wrench flats to reduce printing overhang supports, and (2) added engraved markings on exterior periphery to ID adapter.

HONEYWELL_NORTH_TO_40MM_NATO_ADAPTER_M25.889x1.554_GEN3.stl
HONEYWELL_NORTH_TO_40MM_NATO_ADAPTER_M26X1.57_GEN3.stl
HONEYWELL_NORTH_TO_40MM_NATO_ADAPTER_M27X1.5_GEN3.stl
Gen. 3 features the following changes: (1) completely removed printing overhang support from wrenching ears. and (2) updated chamfers accordingly. And added M25.889x1.554 version, 1% reduction on only the respirator side threaded interface without touching RD40 threads dimensions to be in compliance with STANAG 4155/EN148-1.

Disclaimers/Risks:

1.) Designed two version one of M27x1.5 and another ~M26x157, I do not know if Honeywell/Honeywell North ® respirators have legacy and newer threads to explain discrepancy, or if we are chasing stack up of tolerance from 3D printer, filter female threads, or respirator side male threads. However, the ~M26x1.57 has empirically been proven to work per erniepike.

2.) Use Proper Gaskets
It would appear Honeywell/Honeywell North® filters have gasket on the filter side, but please check to ensure gasket/o-rings properly sealed between cartridge and threads. Source a gasket or O-ring for 27 mm OD or 26.016 mm OD or 1" depending on model that is printed. And also 40mm OD o-ring or gasket on the interior pocket of the RD40x1/7 threads to ensure proper seal between filter or adapter.

3.) Perform Proper Negative Pressure Test
Follow SSPs established by your institution or workplace for further guidance. But in general, don your respirator, adjust straps till taught against face, ensuring no obstructions around the periphery of the seal against face either due from hair, facial hair, or otherwise. Exhale deeply. Cover all inhalation ports. (Typically, most full face or half face respirators have two filters, so cover those intake ports with your hands. If your running only one filter, ensure the opposite port has filter cap in place.) Now inhale deeply. The mask should suck tightly against your face without any air leakages. Re-test if adjustments are required at gasket/o-ring interfaces at the adapter.

4.) Use At Own Risk – Temporarily Solution Only Until Supply Chain Normalizes
3D printing materials are not resistant to many solvents, are water soluble, and degrade when exposed to chemicals, heat, and UV/sunlight. 3D printing this adapter is only a temporarily ad-hoc solution against biological contagions. In addition to using a properly calibrated 3D printer, due to tolerances of adapters, if possible perform hot nozzle pass on all exterior surfaces, to reduce surface porosity. Highly recommended users apply a thin layer of polyurethane clear coat on all exterior surfaces, spray or dip based methods, to help resiliency and durability for repeated sterilization and to reduce fomite transmission in printed infill layers. Once supply chains return to normal, users should purchase OEM OSHA/NIOSH/EN standard approved respirators, adapters and accessories for their institution and workplaces.

Dev. Notes:

04/11/2020 - Initial model release. In work, pending support and feedback from 3D printing community for any fitment and model revisions. I do not have either Honeywell/Honeywell North ® respirator to check measurements.

04/13/2020 - Revised model based on feedback from 3D printing community. The following changes have been made: (1) redone chamber from underside OD to wrench flats to reduce printing overhang supports, and (2) added engraved markings on exterior periphery to ID adapter.

06/05/2020 - Third revisions rolls updated features to be more 3D printer friendly, reworked underside geometry to eliminate overhang support at wrenching ears, and chamfers updated accordingly.

Credits:

Thanks to Clownrock95 for providing the original Honeywell/Honeywelll North ® adapters, original spec of M27x1.5, and special thanks to erniepike's trial and error process to discern better fitment threads.