DIY Dust collection with squirrel cage fan

Hello all,

Sometime back on this group I saw a link to a page that gave a fairly good
description of putting together a dust collector using the squirrle cage fan
and blower from a home furnace. Well I have just such a fan and motor and am
looking for some directions on how to put the thing together.  What I have
is a .25 HP 115v motor.  Fan is approx. 9.5" id. The whole unit weighs about
30lbs. I plan to build a frame around the motor and then a plywood box
around the frame and then either hang the thing from the ceiling, set it on
a stand or on the floor.
Some questions:
1. There is a black and a yellow wire coming from the motor.  Is the first
the hot wire and the second the neutral?
2. I would like to use it at least inpart, to collect the dust from the
lathe when I sand. Would attaching a 4-6" tube to the input side of the dust
collector and the other end directly where the dust flies be a good idea?
3. I also have a rather cheap dust collector (.75 HP 750 CFM) I bought
sometime back.  It has the original bag.  Now I was wondering if replacing
the bag with heavy duty canvas would be an improvement? The canvas would be
the same as used in the old style army duffle bags - really heavy stuff.

Thanks