How to Cut a Straight Line (with a circular saw)

In Jigs and Fixtures, Woodworking Skills by Dan2 Comments

with a circular saw

Not everyone has access to a table saw for making precision saw cuts.  So, how do you safely make accurate cuts?  With a circular saw and a straight edge guide.  For those with a small shop,  a limited budget, or working off site, this is a great way to get very accurate cuts with a simple set up.

While I do have a table saw, I also have two of these guides, one 8′ and one 4′.  They make working with full sheets of plywood safe and simple, especially working alone.

The following instructions are for making an edge guide.


  1. Saw guide: A straight 1×4 or a four inch wide piece of MDF or Plywood with the factory edge.
  2. Base & straight edge: A piece of plywood, MDF or hardboard.  I am using a 1/4″ sheet of plywood, because I already have it.  A sheet of 1/2′ or 3/4″ is more rigid, which many woodworkers prefer.
  3. Glue
  4. Screws


  1. If your straight edge is longer than the base, cut it to match the base.
  2. If you are using plywood for the whole project:
    • Mark a straight line 4 to 5 inches in from one side of the sheet (factory cut edge preferred).plywood 1
    • Cut the sheet along this line and flip the factory edge to the centerlue and screw the two pieces together (make sure the guide is placed so there will be material to trim off.plywood 2
  3.  Place the base of your circular saw against the guide, and trim the rest of the sheet off.plywood 3

Now you have a guide that can be used to cut a straight edge on almost anything.  Rip lumber to get a narrow board, cut plywood  or a glued up panel to size, …

To use the guide:

  1. Measure and mark the cutting line on the piece to be cut,
  2. Lay the guide on these marks and clamp it in place.
  3. Now use your circular saw to make your cut by placing it against the guide.

plywood 4


Lay your material on several 2×4’s or a 2″ thick sheet of foam insulation.  Now you can kneel on the sheet while you cut, and the blade will be protected.

So, how do you cut a straight line with a circular saw?  With a homemade set of edge guides!  I hope you’ll give it a try.  It took me about 30 minutes with left over materials I had laying around.

Let me know if you try it.  How did it work for you?

Please leave a comment if there is something you’d like to see me tackle.



  1. Hi Dan, I saw this jig on “This Old House” shows and having been wanting to make one for years. I use a straight edge board to make 8′ cuts but it is cumbersome to get it positioned accurately. Thanks for the reminder of something I need to do.

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