How to Cut Straight with a Circular Saw? Guide to Cutting Straight Lines on Wood

person operating a circular saw

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Circular saws do not move in a straight line. The saw drifts off our pattern or marks, or the saw blade seizes up when we try to set it back in the right direction. It’s frustrating and a waste of money, time, and materials. But fret not, our woodwork experts have gathered the ways how to cut straight with a circular saw.

What is a Circular Saw?

A circular saw is a hand-held tool with a rotating toothed or abrasive disc used for cutting wood. It is a common tool in construction and repair projects, both big and small. This powerful tool saves time when cutting through various materials such as wood, fiberglass, and metal, among others. 

What Cuts Can You Make With a Circular Saw?

The cuts you can make with this tool are rip cuts, crosscuts, and miter cuts.

A rip cut is done by cutting with the grain of the wood or along the length of a board.

circular saw on working table

A crosscut is done by cutting across the grain of the wood or across the width of a board.

Lastly, a miter cut is done by cutting diagonally across the grain of the wood or across the width of a board.

5 Ways to Cut Straight Lines With a Circular Saw

Method #1: Making Straight Cuts Without a Guide

Step #1: Prop the Board Up

If you really want to use a circular saw without a guide, make sure to fasten your board securely. If it’s a big board, prop up both ends at an even height. Do not fasten both sides of the board, as this may ‘pinch’ your blade as you cut; usually, you don’t fasten the good side you’re cutting away.

Step #2: Make Necessary Markings

Make the markings with clear pencil marks. Use any linear, rigid material or tools to draw your straight line. A long beam level is perfect for this. Adjust your board along with the table.

measuring and marking a wooden board

Step #3: Start Cutting

Rest the saw flat on your board. Pull the trigger and let the blade spin up to full speed. Push the blade smoothly across the pencil line you made, using the notch in front of your saw to guide it.

When Should You Do This

For non-critical woodwork or DIY projects where the material is less than 7 inches.

Method #2: Using a Speed Square to Make Straight Cuts

What You Need

Speed square of about 7 or 12 inches, and clamps.

speed square

Procedure

Step #1

Measure and make a straight cut mark on the workpiece.

Step #2

Place the blade on the mark and place the speed square against the base plate of the saw. Clamp the speed square down if you want to secure it to maintain the position or free your other hand.

Step #3

Upon the blade’s full speed, drag the base plate of the saw against the square and make the cut.

When to Use It

Method #3: Using a DIY Circular Saw Cutting Guide

To make the DIY Circular Saw Cutting Guide

You can also make your it cutting guide, AKA, the crosscut jig for crosscut and miter cut. It will act as a cutting guide for our circular saw. This is similar to the speed square above, but you can make it as long as you want. 

diy crosscut jig

You will need two scrap pieces of 1/4″ plywood or MDF (medium-density fibreboard). The broader plywood will act as the base for your jig, and its edge is where your blade should rest against. 

After positioning the blade, a narrow piece of plywood should be placed against the base plate of your saw, acting as a ‘fence’ for the saw to follow through, so make sure both jig and fence are linear. Glue them together after the alignments. The cutting depth may be shallower, so adjust accordingly.

Procedure

Step #1

Measure and mark the start and end positions of the cut with a straight line

diy crosscut jig
Step #2

Align the edge of the jig (remember, this is where your blade should rest) with the cut line, then secure it with clamp.

Step #3

Drag the saw’s shoe against the fence and make the cut

When to Use It

Method #4: Using a Kreg Rip-Cut

The Kreg Rip-Cut

The Kreg Rip-Cut tool is like your DIY fence above, but with an adjustable fence to make line cuts. This fence tracks the straight edge of our workpiece so we can get an accurate cut all the time. It attaches to the most popular saws and can make linear cuts up to 24″ wide.

circular saw and kreg rip-cut

Procedure

Step #1

Measure and mark the start and end positions of the cut with a line

Step #2

Adjust the fence so the blade aligns with the cut line

Step #3

Using the Rip-Cut’s handle, slowly move the fence along the distance of the workpiece to make linear and even cuts

When to Use It

Method #5: Using a Kreg Accu-Cut

The Kreg Accu-Cut

Like the previous tool, the Kreg Accu-Cut tool lets us cut straight lines with our circular saw. It also attaches to most popular saws, turning them into a track saw or table saw. 

This allows our saw to slide along the guide rail [1] or track of the Accu-Cut. With this attachment, we can make longer cuts with a circular saw, longer than the 24” limit of the Rip-Cut. It also allows us to cut on a variety of angles.

Kreg accu-cut

Procedure

Step #1

Measure and mark the start and end positions of the cut with a line

Step #2

Step #2: Align the edge of the Accu-Cut on the line mark

Step #3

Position the saw on the track and slowly slide for the straight cut

When to Use It

Tips for Making Straight Cuts with a Circular Saw

Keep Your Saw Blades Sharp

A dull blade will damage your motor, drift off the line, or get stuck in the workpiece. Filing can sharpen a circular saw blade. Store the blade properly as well.

sharpening circular saw blades

Know Which Type of Wood to Work With

Knowing which type of wood you are working with enables you to choose the right blade to make straight cuts with a circular saw. Green and pulpy woods tend to bind up, creating the dangerous ‘kickback,’ where the saw jumps backward. 

Check the Circular Saw’s Power

Finally, on how to cut with a circular saw, some saws are gasoline or battery-operated so the power source can be tricky. Thus, their power level should be checked so you won’t run out of juice while cutting.

FAQ

Why is my circular saw not cutting straight?

One of the reasons your circular saw may not be cutting straight is because you fail to use and follow a guide. Consider a speed square, a DIY guide, or Kreg tools. Another reason could be that the blade might be dull, or your saw might have power issues.

How do you cut wood with a circular saw without splintering?

When cutting wood with a circular saw without splintering, you must choose a sharp and good-quality blade. Blades with a high tooth count, carbide tip, and thin kerf make finer cuts. Pass a sharp knife along your markings to shape the fibers of the wood towards the split.

Conclusion

Circular saws are one of the most popular power tools. A guide will enable you to create straight cuts for any DIY project. This concludes our guide on how to cut straight with a circular saw. Always wear safety gloves, safety goggles, particulate respirators, and earmuffs.

Robert Johnson is a woodworker who takes joy in sharing his passion for creating to the rest of the world. His brainchild, Sawinery, allowed him to do so as well as connect with other craftsmen and women. He has since built an enviable workshop for himself and an equally impressive online accomplishment: an extensive resource site serving old timers and novices alike.
Robert Johnson