Update to a previous post asking how to figure angles to cut a curve

How to Find a Cutting Angle

Before we can actually cut anything, the first job is work out the exact angle that you need to cut to.

In almost all situations, the surface you are working with will not be square, although it may appear to be. For example, if you are mitreing two pieces of skirting board together in the corner of a room, chances are that the corner you working in will not be at a perfect 90°

We get hundreds of questions from people about how they can fill big gaps between skirting boards caused because the walls of the room are not exactly at right angles.

With this in mind, it’s essential to firstly work out the exact angle you’re working with.

There are several ways and tools that you can use to do this:

Use Good Old Mathematics

If you are a dab hand with the old maths then it should be easy enough to calculate the internal angles of a triangle that you can create from eth area you are working in.

For example, you can measure equally each side of a triangle and then also the longer hypotenuse line that joins the 2 other lines together and then from that, work out all the internal angles.

Measuring and marking the corner of a room to cr

Measuring and marking the corner of a room to create a triangle to work out angles

We won’t go into the exact calculation required her, but a great explanation on how solving sss triangles (side, side, side) can be found on the Maths is Fun website here.

Use Specific Angle-Finding Tools

As good and accurate as the above maths solution is, sometimes it’s just not practical to spend precious minutes performing a calculation, especially if you are out on site, where time is money.

To this end, there are plenty of manual and digital angle finders available that can very quickly and accurately find any given angle for you, here are some common ones:

  • Standard protractor

Standard protractor used to find and mark angles

    Standard protractor used to find and mark angles

  • Digital angle ruler or digital angle finder

Digital angle rule used to quickly calculate and

    Digital angle rule used to quickly calculate and find angles

  • Site protractor

Starrett large site protractor used for quickly

    Starrett large site protractor used for quickly finding and marking angles

  • Angle measurer

Angle measurers feature both a protractor and ru

    Angle measurers feature both a protractor and ruler for quick and easy angle finding and marking

  • Angled bevel

Angled bevels can be used to quickly find and ma

    Angled bevels can be used to quickly find and mark cutting angles

Each of the above tools can be used to accurately mark a given angle on pretty much any surface. However, if you also want to know what the angle you are dealing with is, some tools may be better than others.

For example the angled bevel will allow you to set and mark and angle, but does not feature any form of visual gauge to tell you what the angle is.

Likewise, a standard protractor is a great tool for marking an angled cutting line onto a given object, but trying to use one to find out what the exact angle of the corner of a room is would be pretty much impossible.

With the above in mind, if you are looking to purchase angle finding tools, make sure you invest in the correct tool that will fulfill all of your requirements.


Calibrating a Miter Saw

For general construction work, it's usually not an issue, however if you need to make lots of accurate square or angled cuts when making furniture, shelves etc, it's a good idea to calibrate a saw first so that the scales indicate angles correctly. It may be possible to adjust the pointer on the miter scale by loosening a screw and turning the pointer. A limit screw is often included on the cutting head which can be adjusted so that the head can be positioned quickly to give square beveled cuts.

Adjustment procedure

For miter cuts, adjust the table to 0º. Cut a section of timber and check the cut end with a carpenter's square. If the result is off, adjust the table and cut again. Keep adjusting the table until you're satisfied with the results. Adjust the pointer if this is possible so it points to 0º.

Repeat the procedure for beveled cuts (cuts with the blade at a variable angle to the plane of the saw table) with the scale set to 0º. The bevel scale is usually at the back of the saw where the cutting head pivots about the sliding rails. There may be a limit screw to set the end of travel of the cutting head, so once you're happy that the saw is cutting at 90º, turn this screw so that it's tight against the head. If the scale pointer can be moved, turn this also so that it indicates 0º.

A mitre saw can make 90 degree square, and angled (mitred) cuts in timber.

© Eugene Brennan

This scale indicates the miter angle. 0 degrees is for cutting right angles. The table can be turned to make cuts up to 45 degrees

© Eugene Brennan

Fine pitch blades are available which give a cleaner cut when cutting e.g. baseboard (skirting) and architrave. A coarse tooth blade is adequate for cutting structural timber.

© Eugene Brennan

Cutting with a miter saw. The guard retracts when cutting and should return when you raise the cutting head

© Eugene Brennan

Tips for Cutting Wood Using Hand Saws and Power Saws

  • Keep your hand saws clean. Remove any rust with wire wool or sandpaper. Lubricate with light oil, Vaseline petroleum jelly or a candle.
  • Keep pencils sharp so that they produce a fine marking line and timber can be cut more accurately.
  • Timber, especially softwood, swells somewhat in damp humid weather conditions, for example if it's indoors in an unheated garage or warehouse. This can result in gaps in floorboards or paneling as it shrinks on drying. If possible allow timber to dry indoors for a few days before using.

Using a tenon saw

Compared to a hand saw a tenon saw is shorter and is less cumbersome to cut wood with. It also has smaller teeth which reduce the possibility of tearing or chipping the ends of wood fibers. It has a rigid spine that prevents the blade from curving and warping too much as you make the cut.

When cutting, position the blade and teeth of the saw to cut along the waste side of the pencil line than cutting along the center of the line. The slight error in length because of the kerf of the saw when cutting on the center of the pencil line, can cause a greater error.

How to Accurately Mark an Angle

Now that we have accurately measured our angle and also checked to make sure this measurement is correct, the next task is to mark our angle onto the surface we wish to cut.

As mentioned, for this example we are going to be cutting a shelf to an angle so that it fits flush against our angled stud wall when the back edge is flush with the flat wall behind.

Area for shelf to be fixed to, with flat wall to

Area for shelf to be fixed to, with flat wall to the rear and angled wall to the left

There are two solutions that can be used to mark our shelf:

  • Use the angle set on an angled bevel
  • Use our protractor

Using an Angled Bevel to Make a Cutting Mark

This is probably the quickest and easiest solution of all.

On your object, in this case our shelf, measure and mark the point at which the angle should start. Make sure that you make your mark in the correct place!

As our angle is already set on the bevel itself, we can simply place the bevel onto the item we want to mark so that the lip of the stock is flat against the objects surface and that the point at which the blade starts to angle is directly on the mark on the object that we made above.

Using a pen or a pencil, simply draw your cutting line from the point on the object along, using the blade as a straight edge.

With the angled bevel in position, mark along th

With the angled bevel in position, mark along the edge of the blade

Your cutting line has now been clearly marked, ready for actually cutting.

Using a Protractor to Mark Cutting Line

We can also use our protractor to mark our cutting lines and points.

Firstly, place the protractor so that its centre point is directly over the mark we made above that depicts the start of our angled cut.

Next, work around the scale on the outer edge of the protractor until you get to your desired angle in degrees. In this case 135° and then mark this point with a pen or pencil.

Using a protractor to mark an angled cutting lin

Using a protractor to mark an angled cutting line

With our marks now made, it’s simply just a case of joining them up using a pen or pencil and we should then be left with a clearly defined cutting line.

Joining up marks to create a cutting line

Joining up marks to create a cutting line

As said, arguably the quickest and easiest method is to just set the angle using your sliding bevel and then mark against the blade, but if you want to mark the exact angle as set by a protractor then go with this method.

How can I contact you to ask about How To Figure Angles In Woodworking?

All the results for How To Figure Angles In Woodworking searching are available in the Howtolinks site for you to refer to. In case, you are still confused on some problems about How To Figure Angles In Woodworking, you can contact us via our email to get our best support.

Things you will need

  • Miter saw, miter box
  • Wood pieces
  • Hand saw
  • Tenon saw
  • Sharp pencil
  • Marking knife

Here’s how to cut angles using a miter box:

1) Prepare the miter box

Source: https://makezine.com/projects/make-straigh

Source: https://makezine.com/projects/make-straight-wood-cuts-with-a-miter-box/

Place the first piece of molding in the miter box to hold it in place. Place the saw in the appropriate slots and set the angle.

2) Cutting wood with a miter box

Source: https://makezine.com/projects/make-straigh

Source: https://makezine.com/projects/make-straight-wood-cuts-with-a-miter-box/

Cut the first piece of wood using the miter box. Now place the second piece of wood in the miter box and hold it in place. Place the saw in the slots, so that the second cut will match the first one you made.

Cut the second piece of wood. The two moldings should fit neatly together.Keep in mind that you must always measure twice but cut once. Work on your cuts slowly, otherwise your cuts will not be precise and the corners will not be able to fit together.

Section 2: General Idea of Bevel Cut

Usually, angle cuts are often at 90 degrees. However, when you cut at an angle other than 90 degrees, this is a bevel. More so, the setup of the square edge comes with full dimensional lumber. It means that the angle of the bound’s edge and face is typically 90 degrees. Therefore, any angle different from the usual angle will need adjustment. It leads to the invention of bevel cuts.

Moreover, bevel cuts are very useful for decorative purposes such as interior moldings, cabinet trims, etc. Apart from the table saw, there are other instruments to make a bevel cut. Such instruments are jigsaws, routers, or circular saw; however, jigsaw typically fails to provide a precise cut. 

Figure 3: Close-up image of angular cut.


  • Operating a table saw can be dangerous if you don’t wear the proper safety gear. Always put on safety glasses, a dust mask, and earplugs.

    Thanks! Helpful Not Helpful

  • Keep your hands away from the saw blade at all times while it is active. Turn it off when it isn’t in use.

    Thanks! Helpful Not Helpful


Join All Access

Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.

Start Your Free Trial