My version of a downdraft and outfeed table. This outfeed table also serves as a whole shop air filter
when run periodically during the day when much airborne dust is accumulating in the shop.
I also decided to build it as an integral part of the tablesaw with mitre gauge slots and
an opening for the blade guard. I had to build a 6 in. extension onto the downdraft table to
enable this. The extension is attached to the downdraft table with 4 in. angle brackets
spaced evenly along its' length.

I can now move the table away from the tablesaw for maintenance, and the weight
of the downdraft table keeps it solidly in place with built-in levelling feet all around.
The heavy duty handle at the front enables me to grip the table to move it forward
or sideways.

When the levelling feet are raised at the tablesaw end, there are 3 casters which enable
me to roll the downdraft table away from the tablesaw.

The top is a grid of 1 in. holes spaced 2 in. apart in either direction. Drilling these holes can take
upwards of 2-3 hours or so. The tabletop itself is a particulate board with melamine surfaces
on either side. Holes were drilled using a 1 in. forstner bit.

More information and detailed CAD plans on how to build this downdraft table
can be found here: Downdraft Table Plan

The blower and motor assembly is surplus and purchased for approx. $50.00 CDN with taxes.
The motor can be purchased either as an integral part of the blower, or separately.
I decided to purchase the motor independently of the blower, and construct my
own swiveling adjustable motor mount for it.
The motor itself is 1/3 HP and very adequate for the job. The motor is not a TEFC type,
since it is unlikely this part of the downdraft table will accumulate any dust.
A TEFC motor is an option, or if available, easily adapted..

This portion of the downdraft table is sealed with silicon caulk and I also went over any
seams with a flashlight to ensure there is no air entering aside from through the 4 filters
in the dust pit area.

The filters are arranged vertically in pairs. The filters are all pleated filters. I have had success
with this type of filter in a ceiling mounted air cleaner I built a few years ago, and their price is
reasonable at approx. $5.00CDN per filter. There is a short piece of wood and rubber band
assembly which keeps tension on the filters and serves to keep them tightly against the
blower housing portion of the downdraft table.
Very simple affair to clean the filters and dust pit with a vacuum. The top is removed,
the inside is vacuumed, and the filters are then removed and vacuumed individually.

In my tests, it is sufficient to vacuum the inside with the filters in place every few days or so.
A thorough vacuuming of the dust pit with filter removal is probably due on a weekly basis,
depending on the amount of sanding you perform, and the amount of airborne dust in your shop.