I got all hyped up about building a European style Riving knife for my saw.
This naturally meant that I would have to do something about the blade
guard. More importantly, dust collection on a table saw seems to be a
fruitless quest, if you don't do something about the saw dust above the
table. I was extremely disappointed when I connected a 2hp collector and
installed a zero tolerance blade insert at the same time, only to discover
that I still got a heaping helping of sawdust when I ripped with a high
I am combining designs from multiple sources to achieve my own personal
priorities, with extremely good dust collection being at the top of the
list. I'll report progress as I muddle through this.
The biggest unknown to me was the cost and availability of Lexan -- seems
this is a must for blade guard. Today I went to a local plastics supply
house and was pleased to be introduced to their cutoff stock. I had
drawings of the parts I needed and a gentlement in the sawroom helped me
search the cutoffs. He also gave me some advice on cutting and routing the
stuff. Overall it was a good old fashioned top service experience.
For those of you thinking about something like this, Lexan (GE brand of
polycarbonate) sells for roughly 14-15 cents/cubic inch in my area (Houston,
Texas). I got a 1/2 inch x 23 inch x 12 inch piece for $20 and a 1/8 inch x
10 1/2 inch x 23 inch piece for $4.
So what am I going to do with 1/2 thick lexan? Well, in case someone shoots
a bullet through my shop, it might have a chance at stopping it. <grin>
Otherwise, I figure I'll have one heck of a blade guard.
I'm thinking of doing the same thing. I found this web site,
http://www.woodisourart.com/tablesaw/bladecover.htm , detailing one design.
I'd be interested in seeing pictures of yours. Will you post some pictures
on ABPW when you're all done?
Gary in New Tampa, FL
The site you referenced is one of the inputs into my design. Yes, I'll post
pictures. My brother suggested I make a mockup of the guard before making
the real thing. Boy, am I glad he suggested. I built a 1/2 plywood model
and learned all kinds of things by actually putting it on top of the table
saw. I also learned that I am lousy at setting up non-standard angles and
getting it right in the first 3 cuts. I would guess that many of these
homemade systems are copied from commercial ideas and there area few that
have original thinking. Some of the variable dimensions I've seen on
1. What is the leading angle on the guard? The website you referenced uses
an especially low 40 degree angle. The factory guard on my jet saw uses a
45 degree angle. I suspect the 40 degree angle is used to make rising up
over wood as easy as possible. It sure contributes to a "pointy" front end
on the guard, though.
2. Is the second angle cut at the top front of the guard really necessary? I
suppose it may add some visibility by creating a little window to look
through. But it makes the other angles and heights really difficult to get
right. One degree here and a quarter inch there and you end up with the
guard sitting on top of the blade.
3. Should the guard be tall enough to clear the blade, even if it falls on
the table? Several guards I've seen are not tall enough to meet that
4. Is dust collection efficiency worse on a tall blade guard than a short
Regarding my primary quest of dust collection, I'm very intrigued by a
design shown in the Workshop Book by Scott Landis. It has sliding sides and
a flexible plastic flap at the front and rear of the guard. The idea is to
make as tight a seal around the blade/wood stock for getting good dust
collection. These moving parts really do not add any protection to the
already intact guard housing underneath. I'm going to build these features.
If they don't work, I can just rip them off and will still have a functional
The Workshop Book design also has a really strange suspension, dust
collection pipe set up. I'm separating the guard into two pieces - the
guard and its suspension system. I figure if I get the guard right, I can
always monkey with the suspension system later. Anyway the suspension
system I reference has a vertical column suspended from the ceiling. The
column is hollow with 1/2 devoted to a hardwood counterweighted slider to
which the guard is attached. The other 1/2 is a hollow square dust
collection duct. The original builder of this whole thing made good use of
common materials that are cheap.
Darn, I write too much. Sorry to bend your ear. I'll save other detailed
stuff for a website, assuming this is successful as I anticipate it to be.
There are several home-made guards on the web. I thought I had bookmarked
them, but I either didn't or I stored them in a place where I could easily
find them and now I can't. I've thought about building one myself as it
seems pretty easy to do. I think we're just talking about a little plastic
box with a hole in the top. I would make it tall enough to clear the blade
even if the blade is at full height and the guard is on the table. Also
wide enough for you widest dado setup. Raise your blade to full height, put
a piece of plywood against the side of the blade and trace around the blade.
Isn't this the minimum size of the box sides? Add yourself another inch or
so around the perimeter and square it up. Then you can add the angle on the
front edge if you want without worrying about the 1/4 inch here and there
that you're concerned about. I have a hunch you are worrying too much about
completely sealing the guard up. Experiment with a plywood guard and see if
you get most of the dust, I bet it won't be too hard to do.
In my thoughts, the trickier part is how to hold the guard up. I move my
saw around so having something attached to the ceiling is out of the
question. It has to be attached to the saw and I'd like it to be
spring-loaded so I don't have to fiddle with it everytime I change wood
Larry C in Auburn, WA
"Bob Davis" < firstname.lastname@example.org> wrote in message
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