Tom Gardner wrote:

I want to bid on a part for a floor washing brush. The company made a
bunch of PVC tubes 1" ID X 1.375 OD x 12" long. It's covered with a
material that looks like carpet...'kinda. It works great until it gets
hot then it gets bendy. The company's lab came up with a fix that
involves a taking a Derlin tube that's 1.040" OD x .75" ID x 4" long
with a .312" slit along the side and pressing it into the middle of the
12" tube to act as a stiffener.

What's the cheapest way to make these? Is there a better solution?
They need 10k+ of these. They will supply the Derlin material.

Cut to length with a standard automatic bandsaw if you have one,
otherwise use a table saw with a jig to allow fast cutoff feeding from
the presumably long stock.

Make a custom chamfering head that has a bore to match the OD of the
tube and a standard insert to cut the chamfer (look for HSS inserts).
Incorporate the depth stop in the head so you just push the tube in
until it bottoms out on the flat part of the front. Continue a bore and
a side port for chip evacuation and surround that with a connection to a
shop vac / dust collector. Mount the whole head on a basic motor so you
don't tie up any normal machines.

Do the slotting on a cheap table saw, with a holding fixture for the
tube. Something with a chamber in the bottom you put the tube into where
the tube sits slightly past the bottom of the fixture so you can apply
down pressure to keep it from rotating. Position the operator and parts
bins so they can pickup a tube, place it in the bottom of the fixture as
they slide it over the saw table, run it over the blade between a pair
of fences perhaps 2" apart, and as they run it off the end of the table
the completed part falls into a bin. Minimal labor and pretty fast.

For insertion do a simple pneumatic press setup where you drop a brush
and a tube in the press fixture and hit the button or foot pedal to
press in to the preset depth. This could be automated easily with some
gates to allow you to just load some feed bins and let the cycle work
automatically.

If the quantity was higher or this was to be a regular job, a lot more
automation could be applied pretty easily.