I want to make a blower to
use with my 2 bucket cyclone ’cause this shop vac is
just too damn loud. I want to use an induction motor and I think the most suitable
one from my collection is probably this one. This motor is a two third
horsepower motor from a really cheap table saw. And what’s cool is it
has these flanges that used to be for
mounting a blade on here and that will be very convenient
for mounting the impeller. And I have to figure out if
this motor is powerful enough so I’m gonna test this by just
spinning a blade in free air. The current was out of
range of the power meter so it definitely overloaded. I have
to shorten those blades a little bit. 14 amps is still too much
so I gotta shorten it some more. Experimenting some more I cut a
little bit of width off of here and that allowed me to extend
the length a little bit. And with that I might be able to get
away with a rotor thatch as large as 34 centimeters or
about 13 1/2 inches. I just spent a bunch of time
designing the impeller and the spiral housing on the computer. And I went with a 35
centimeter diameter impeller. That’s about 14 inches.
Which is quite large Normally that size impeller is for
like 3 horsepower dust collectors. So, with this motor its very iffy. If it’s a bit too large I can always
cut a little bit off the edge. But I figured with the
backward curved blades and keeping it relatively thin I should
be ok with a two third horsepower motor. And I also printed out cutting templates for all the curved
veins that go on the impeller. Rather than glue a
paper template on here I just recreate that shape
using compasses. Dividing a circle by 6
is easy and then I bisected those to get
divided by 12. And I marked the angles where these
are supposed to start and end. And I’m just checking that if I place
these fins on the tick marks I made that looks about right. Hmm. Need more hand planes. Oh, I think I can use those guys. While that’s drying I’ll start
working on the spiral housing. This time around I’m building up the
housing in layers of short pieces. And once I’ve got these all
sandwiched and glued together I can cut them out
on the band saw. This glue-up is turning
out to be not quite as straight forward as I
was hoping it would be. Because the clamps keep
getting in the way putting the template on it. So, almost going freehand. I’m balancing the impeller on a marble to see if it has the tendency to
tip to one side or the other. And it pretty consistently tips this way. So I made this counterweight
to glue in here. And that makes it pretty much
even, whichever way it goes. So I think that mostly balances it. Well, here’s a major screw-up. It turns out my motor runs this way. And these veins need to be
curved away from the rotation. It needs to go this way
otherwise it’s way too inefficient. So, I’ll have to try and figure out
how to reverse that motor. And cursing a fair bit I’ve come up with another solution
which is to cut out the middle of this propeller. And then just flip it over and make this the mounting side and now I’ve got my veins
curving the right way. Have to be very careful to get this on the right way right away because if I slide it
around too much I spread the glue. And it’s gotta be
lined up perfectly. Otherwise this things gonna
be really off center. It’s much easier to work out
where these segments go if I clamp it in a way that
I always have the template handy. So no clamping from this side
this time. Got the motor put back together. And the impeller mounted
and it runs pretty round. Although I did have to shim
a little bit back here to achieve that. Only 9.9 amperes.
I could have made it bigger. 37 centimeters of suction. Not bad for a dust collector. So based on my readings this little one should be able
to out-suck the big one. So let’s give it a try. And it really does out-suck the big one. It really sucks.