40MM NATO (RD40X1/7) to MSA® Comfo Classic Threaded Filter Adapter

thingiverse

Human: 40MM NATO (RD40X1/7) to MSA Comfo Classic Threaded Filter Adapter ============================================================= This innovative design for a 40 MM NATO (RD40X1/7), gas mask thread, to MSA Comfo Classic threaded filter adapter makes RD40x1/7 threaded full face CBRN masks compatible with MSA Comfo Classic series threaded chemical, combination, and particle filter cartridges. Part Description: ================ 40MM_TO_MSA_COMFO_ADAPTER_MONO.stl Single piece construction adapter, for MSA Comfo filters that do not require clocking, sized based on original threads provided from JDMac174 at 64.212 mm. https://www.thingiverse.com/thing:4253780 40MM_TO_MSA_COMFO_ADAPTER_MONO_OLD.stl Single piece construction adapter, for MSA Comfo filters that do not require clocking, sized based on 64 mm DIA threads provided from arkurb. https://www.thingiverse.com/thing:4259079 40MM_TO_MSA_COMFO_ADAPTER_MONO_DIA_64_GEN2_1.stl 40MM_TO_MSA_COMFO_ADAPTER_MONO_DIA_64.212_GEN2_1.stl Gen 2 features engraved markings to identify adapter. Engraved at 12-6 O'clock positions, removed 3-9 O'Clock markings as it resulted in an STL file larger than 262 MB upload limit at thingiverse. Disclaimers/Risks: ================ 1.) Use Proper Gaskets Requires gasket/o-ring, below bayonet to ensure proper seal between cartridge and bayonet. Source a gasket or O-ring with a nominal outer diameter ranging from 64mm or 2.520" to 64.212 mm or 2.528". 2.) 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. 3.) 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: ========== 04/07/2020 - Initial model release. In work, pending support and feedback from 3D printing community for any fitment and model revisions. I do not have either MSA Comfo Classic respirator or filters to check measurements. And relied on the two community models linked above, and oversized female/nut threaded side threads for 0.16 mm clearance. 04/14/2020 - Updated models with engraved markings to identify adapter. Engraved at 12-6 O'clock positions, removed 3-9 O'Clock markings as it resulted in an STL file larger than 262 MB upload limit at thingiverse. Credits: ====== Thanks to JDMac174 for just releasing a original MSA Comfo Classic to 3M bayonet adapter that enabled me to infer the MSA bayonet geometry, and for akurb for remixing it to fit the older respirator.