This is the followup/continuation of the thread "Dribble Cooling on a
lathe" started 26 May 2009. where much of the setup is described.

As I experimented with dribble cooling, a few things became apparent.

1. Even a dribble yielded a nice puddle in the chip pan, and it was a
nuisance to clean it up because of the fine chips. It would be nice to
be able to wash the pan down.

2. Dribble really doesn't work when facing. One needs a flow, so one
can hit the face. And the work flings coolant.

3. Parting off wants a lot of coolant, a flood really.

4. The lathe came with a shop-made 5/16" hole in the right front corner
of the chip pan. Why this modification was made soon became apparent,
as this corner is where the coolant from parting off collected while
running with the hole corked. I think the prior owners put a bucket
under the hole.

So, I decided that I need to be able to vary between dribble and flood
as needed, and that the bucket approach was likely to be clumsy, so I
needed to make the 5/16 hole into a real tygon tubing fitting, so I
could fit a drain leading back to the coolant pump.

To do this, I drilled the 5/16" hole out to 3/8" using a unibit, used
paint stripper to remove the battleship gray paint around the hole,
polished the steel with a fiberglass brush, and soft soldered a short
piece of 3/8" copper tubing into the hole using a big propane-air torch
that runs off a picnic bottle. (One must use tinners flux to solder
steel; plumbers flux won't work.)

Now the lathe has two drains, one large (1/2" tube) and close to where
the cutting is done, the other a bit smaller (3/8" tube) at the lowest
point, both leading back to the coolant pump.

As a test, grooved and parted-off a 0.75" diameter 1018 rod using HSS
bits and cutoff blade. All went very smoothly, without noise or drama.
The sidewalls are a bit rough, but the groove bottoms are quite smooth.

I also added a T in the tygon tube from coolant pump to the needle-valve
manifold, providing a coolant feed to a handheld 1/8" nozzle that I use
to wash the chip pan down, washing the chips into the coolant pump
basket strainer.

The next thing is to make a tube with a little brass nozzle soldered to
the tip, so I can generate a high pressure low flow stream. The 1/8"
tubing is a bit springy, and vibrates with machine vibration, and may
restrict flow to the nozzle, so I'll use 3/16" copper tubing.

On the manifold, I have two needle-valve assemblies, one with 1/8" the
other with 3/16 compression fittings, so it's easy to change (or
replace) tubes and nozzles.

Probably the next project will be a shield to catch flung coolant. I
even got some on my eyeglasses.

Joe Gwinn