I'm a total newbie to woodworking, so i apologize in advance for the
ignorance. The question is, how do i cut a precise angle with a circular
saw? I'm building a couple sawhorses for a bigger project, and i can do a
bevel cut, but can't figure out how to measure and cut a precise angle
(other than 90 degrees... i figured that one out) ;] Is there some kind of
gadget that acts as a guide, and is adjustable from 0 to 90 degrees?
Thanks for the help,
You might get a kick out of an "almost" product described at
Note: Please do NOT attempt to order. This is not a current
product and the web page was only a prototype for a business that
never got off the ground.
Porter-Cable had a similar product a whole bunch of years ago. I tried it,
didn't much care for it.
"Facts are stubborn, but statistics are more pliable." Mark Twain
The idea behind the "almost product" was that after "calibrating" the wooden
spar all you would need to do is mark your cut and align the end of the
wooden spar with the mark. When using a speed square you have to take into
account the offset between the edge of the base of the saw and the blade
location. Lee Valley sells two similar saw mitre gauges, see below.
Doug nailed it. Used with care, it combines extreme accuracy,
speed, durability, and convenience - and delivers those benefits
equally well to complete newbies and old pros.
It died as a product because I couldn't afford the entry fee -
cost of stamping dies + cost of minimum initial production order.
The good news is that all it takes to build your own is 30" of
1"x1", a 12"x12" piece of 1/4" plywood, glue, and screws.
Hey, neat! I often use a handheld saw when roughing out the pieces from
1x12x8' stock as they are too big and unwieldy to be convient on the
chop saw or TS. Or somethimes I use a handsaw cause the circular saw is
just to much bother, but that jig would make it convient enough ....
Gonna make me one of those.
It depends on what you are trying to cut. For sheet goods, like plywood,
simply mark the degree angle you need using a protractor and extend it
across the sheet. For stock boards (1x4,1x6,2x4, etc) clamp a speed square
to the board for a 45 degree cut, or mark it using a protractor, then clamp
a guide so that you have something to run the base of the saw against as you
Yes, you can build an adjustable guide, but unless you really need an
accurate cut, and need it often using a cir saw, forget about spending the
time to do this...
Probably, but in this case, a little knowledge is better than gadgets,
which are fiddlesome and often inaccurate.
For a hand held circular saw, I would use a good square, a rule, and a
straight edge to guide the saw. To cut a given angle, use trigonometry to
determine the lengths of the two perpendicular sides of a triangle
containing the desired angle.
<crude ASCII art; use fixed-pitch font>
+ <-- mark 2 here
O | \
| T \
A ^- start of cut
`---- mark 1 here
</crude ASCII art>
Suppose you want to cut angle T. You need only remember that
O = A * tan(T)
Use a calculator to find tan(T).
Make a mark an arbitrary distance along the edge of the wood from the
point where the cut will start. This is side A (Adjacent) of the
triangle. Use whatever length works well for the piece of wood to be cut.
Multiply A times tan(T) to get the length of O, the side Opposite the
desired angle T.
Using a square, make a second mark at distance O from the first mark,
perpendicular to the edge.
For example, to cut a board at a 30-degree angle:
tan(30) = 0.5774 (approx)
Mark 1 for side A, say 10" long.
Mark 2 for side O = 5.774", as close as the rule allows.
Use the straight edge to guide the saw from the start of cut through
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