On Thu, 01 Sep 2016 10:39:59 -0700, Jeff Liebermann
wrote:

I'll post a photo when I find mine, but really, it's quite simple to
build.

I decided it was easier to build a new bicycle pump pressure gauge
comparator contraption than to remember whom I loaned it to[1]:
http://www.11junk.com/jeffl/pics/bicycles/misc/slides/Bicycle%20pump%20pressure%20gauge.html
Those are 2 Schrader bicycle valves masquerading as gas line pressure
test fitting:
https://www.plumbingsupply.com/testing.html#testgauge
and a generic pressure gauge. All the fittings are 1/4" NPT. However,
the prices were a bit high at the local Ace Hardware store. $10 for
the gauge, $5/ea for the valves, and $8 for the Tee. Ouch.

It could have been built without the Tee and only one Schrader valve
head. To do that, you could just buy the above gas pipe test kit, and
plug up the pipe hole with a 3/4" NPT plug. However, I want to also
use it to compare two pump gauges, measure the pressure using an
external pressure source, and possibly install a small surge tank in
order to obtain more accurate pressure readings. Those all require
the 2nd fitting.

I previously mumbled something about removing the valves. Don't
bother. The pump head will hold the valve open. Also, my Blackburn
floor pump has a head with requires that the center pin in the head be
pushed inward, or the Presta side of the pump head will leak air.

Testing was easy. I just pushed down on the floor pump while watching
both gauges. There both read identically. Since the volume of this
affair is smaller than the volume of one pump stroke, this test is
rather quick and mostly effortless.

None of this will do anything to repair a broken gauge, but should be
quite adequate for testing any repairs or adjustments.


[1] I just realized that this is the 4th or 5th one of these that
I've built. I gotta learn to stop loaning them to friends.

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