40MM NATO (RD40X1/7) to Portwest® Bayonet Filter Adapter

thingiverse

40MM NATO (RD40X1/7) to Portwest® Bayonet Filter Adapter =============================================== This was originally only a proof of concept design for a 40 MM NATO (RD40x1/7), gas mask thread, to Portwest® bayonet filter adapter. Originally an MSA® version was requested recently by Daramcgrath, and just recently confirmed the geometry fitment of bayonet to filter. And now updated as prototype adapter to maximize cross compatibility of full face CBRN RD40x1/7 threaded mask with Portwest® line of bayonet filters. Part Description: ============= 40MM_TO_PORTWEST_BAYONET_ADAPTER_PROOF_OF_CONCEPT_ONLY.stl Initial model with rough Portwest® bayonet geometry from scaled images alone. 40MM_TO_PORTWEST_BAYONET_ADAPTER_MONO_GEN2.stl Gen. 2 features the following changes: (1) added engraved markings on exterior periphery to ID adapter, and (2) OD of bayonet changed from estimated 31.5 mm to 33.5 mm, bayonet thickness changed from 2.5 mm to 3.0 mm, and on the base/cylindrical extrusion diameter changed from 27 mm to 28 mm. Disclaimers/Risks: ============== 1.) This is a proof of concept only – model in work. [UPDATED - Now Prototyped, Gen. 2 Geometry Works] 2.) Use Proper Gaskets Requires gasket or o-ring on the underside bayonet to ensure proper seal maintained between cartridge and bayonet. 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: ========= 04/09/2020 - Initial model release. In work, pending support and feedback from UK and European 3D printing community for any fitment and model revisions. I do not have Portwest® respirators or filters to check measurements, but thought making an 40MM one would gander more attention perhaps, as maybe MSA® respirators perhaps are limited overseas. 04/13/2020 - Revised model based on feedback from Daramcgrath. The following changes were made: (1) added engraved markings on exterior periphery to ID adapter, and (2) OD of bayonet changed from estimated 31.5 mm to 33.5 mm, bayonet thickness changed from 2.5 mm to 3.0 mm, and on the base/cylindrical extrusion diameter changed from 27 mm to 28 mm. 04/22/2020 - Received confirmation from Daramcgrath that the bayonet geometry interfaces well with the Portwest® filters. Credits: ======= Special thanks to Daramcgrath for taking the time to pull the geometry on the filter side to ensure mating bayonet surfaces are true.