On Tue, 24 Jan 2017 15:13:12 -0800, wrote:

I made up a little cylindrical reservoir that is pressurrized by a
piston. I tried the injector with some oil that was thicker than the
lube I intend to use. The result was oil that just dripped from the
injector. An online look at DIY injector service made me wonder if the
filter was restricting the flow so I removed the filter. Then, using
oil thinned to the approximate viscosity of the real lube, I tried the
injector again. It squirted pretty good at 30 PSI. The next thing to
address is the reservoir. I'm not sure if a piston sealed with an
O-ring is the best solution for applying pressure. There might be
stiction of the O-ring so that the piston may not move smoothly enough
causing erratic fluid delivery. An inflatable bladder would probably
work well but I have no idea where to get something like that. I'll
have to see if there is some sort of cup seal that would work better.
In any case I don't think it's a good idea to have the lube exposed to
the shop air, even though it's filtered, because there will always be
a little moisture in the air. When I need pristine air I do have a
nice refrigerated air drying system with particle filters but I don't
generally use it. The other thing I need to chnage is the spray
pattern. Not sure how that's gonna get done yet. Maybe just a
deflector slipped over the injector will work well enough and that's
my first option. I've got a 555 timer system running and I will be
weighing the oil squirted out once I have the pattern deal figured
out. Once that's done then the timing can be set. I'd like to have
some sort of knob to turn that has a linear relationship to the amount
of fluid delivered. So that a setting of 4 would be twice as much
fluid delivered as a setting of 2.
Eric
I know, it's bad form to reply to one's own post but there it is. The
nozzle idea didn't work. I had hoped the fluid would be coming out
with enough velocity to deflect and follow a new path. Instead the
nozzle just started to dribble. I watched the cylinder piston move
though and it moves pretty fast so O-ring seals may be OK. The
existing injector orifice plate holes must be drilled at an angle
because that's how the jets of fluid come out. The holes are about
..008" diameter so I'm thinking about trying to drill them straight
with a .012" diameter drill. Maybe if the drill bit is held so that
only about .05" is unsupported it will be stiff enough to avoid being
deflected too much by the existing holes as they are opened up. Maybe
I need to see if I can remove the orifice plate and replace it with
one of my own. Perhaps a large hole can be machined in the existing
orifice plate and a new one added directly on top that has a hole
pattern better suited to applying lube in a straight line.
Eric