Vango Tempest pump to Boston deflation valve (airtent/inflatable kayak) adaptor

The standard valve for many air tents/inflatable kayaks and pack rafts etc is the “Boston” valve.  One hole for inflation and deflation, but two different caps; with the small cap removed the inflatable can be blown up, as it includes a small one-way valve.  To deflate, the second, larger cap must be removed, as that contains no one-way valve and the air can simply be let out.

Some of us use hand pumps, but I recently bought the Vango Tempest rechargeable pump.  Excellent bit of kit, by the way - you can set the desired pressure from 0.5bar to 10bar, it's not too noisy, inflates quite quickly yet has enough battery charge for many inflate cycles AND can still function as a power bank.  It can deflate as well as inflate.

Only problem is,  those Boston valves (like the ones on my tent) don't play nicely with the pump; that when air is sucked out of the smaller hole, the one-way valve closes and nothing comes out.  And none of the supplied adaptors fit into the larger, deflation hole.

Solution - 3D print something!

It didn't actually take me very long to get this right - the threads to the Vango Tempest pump are particularly easy.  The Boston valve threads are closer and tighter - the model works perfectly for me printed at 100% in black Overture PLA, but if you use a filament with different expansion properties you might need to adjust the X and Y dimensions by 1% or so.

Print in small layer heights (I used 0.08mm) and experiment with supports (as results vary according to type of support material).