On Wed, 6 Sep 2017 15:08:05 -0700 (PDT), wrote:

On Wednesday, September 6, 2017 at 12:07:47 PM UTC-7, Duane wrote:

Or just buy a decent pump and forget about it.

As Jeff asked - what is a "decent pump"? A pump that works good
on a high pressure racing bike takes forever to inflate an MTB
tire. With almost all of the pumps these days using that awful
filler valve https://tinyurl.com/y84dcpqn simply isn't right
for other applications.

The air chuck (head) certainly could use a few lessons from the
automobile mechanics, which use a proper locking air chuck something
like these:
https://static.grainger.com/rp/s/is/image/Grainger/2HKY3_AS01
https://veesun.com/images/air_chuck/731423.jpg
They grip well, don't fall off, don't blow off at 150 psi, and usually
survive getting trampled. However, they're for Schrader valves only
and are not made for Presta. The closest equivalent is this device:
https://www.excelsports.com/main.asp?page=8&description=Hiro+Side+Lever+Lockin g+Disc+Chuck&vendorCode=SILCA&major=12&minor=4
Yes, it's USD$100.00 for a locking Presta air chuck. You can find
something cheaper, but it's not locking:
http://www.lezyne.com/product-dpumps-acc-slipchk.php
About $10. I have two of them. They work for about 20-30 inflations
before the rubber O-ring wears out. Notice that it includes 6
replacement O-rings. More Presta tire chucks:
https://www.google.com/search?tbm=isch&q=locking+presta+tire+chuck
You can find other Presta heads, but they will probably be in the form
of a combination Schrader and Presta head, which is the problem. When
one combines the two valve types in a single head, the only mechanism
that works for both is the "hole in the rubber plug" type that grips
the threads on the outside of the valve stem.

One possible solution for Presta is to use a Schrader to Presta
adapter, but those are awkward and clumsy and tend to fall off if left
on the valve:
https://www.youtube.com/watch?v=ncY1PEgSbI0

In my never humble opinion, the best solution is a pump head with only
one type of valve arrangement. The hose and head should be removable
from the pump using standard pneumatic fittings. If a floor pump, the
gauge should be near the handle, where I can see it, not on the floor,
where I need my distance eyeglasses to read the dial.
http://www.bermstyle.com/wp-content/uploads/2014/12/20141116-turbocharger-pump-6281.jpg
Extra credit for selecting large numbers and high visibility colors
for the dial, instead of a black dial with a red pointer, which is
almost invisible in the dark:
https://s3-eu-west-1.amazonaws.com/images.linnlive.com/9aee59d2c18ef6fce9ea759285f794e3/0f3a7dbd-0a6f-4bf9-9ff5-50c64bc3c06f.jpg
I'm sure there are more obvious improvements but these will suffice
for now.

As for tire pump displacement vs pressure, take a look at a better
than average hydraulic wood splitter. All these use two stage
hydraulic pumps. There first stage offers high volume, low pressure,
to rapidly move the splitting wedge from the open loading position, to
where it begins to hit the log. Once it hits the log, it switches to
low volume, high pressure, which is what's needed to bisect the log.
The same could be done with a bicycle pump design. The bicycle pump
would initially be in high volume, low pressure mode up to maybe 10-15
psi, where it would switch to low volume high pressure to reach
operating pressure.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558