How to Adjust and Calibrate a Miter Saw for Accurate Cuts

Co-authored by wikiHow Staff

Last Updated: July 15, 2022 References

Ah, the good ole miter saw. It’s always there when you need it, but if it’s cutting crooked, you may need to make some adjustments to keep it cutting properly and accurately. Fortunately, it’s actually a lot more simple than you may think. With the proper tools and the right approach, you’ll have your saw adjusted in no time. We’ve answered a few common questions that folks have about adjusting their saws to make the job even easier for you.

Question 1 of 6:

Why is my miter saw cutting crooked?

You may need to make some adjustments to realign the saw blade. If your blade is cutting crooked, there could be a few possible reasons why. The most common cause is not properly clamping down the material you’re cutting. Other possible reasons your cuts aren’t straight or accurate include a damaged blade, an unstable fence (the flat piece of material mounted on the saw table), a broken bevel gauge, or some sort of malfunction with your miter gauge. Try adjusting the fence or replacing any broken parts to see if that corrects the problem.^{[1]
X
Research source}

Question 2 of 6:

How do you adjust a miter saw blade?

1
Use a speed square to see if the blade needs to be adjusted. A speed square is a super handy triangular marking tool often used by carpenters. First, disconnect the power from your saw and place the speed square upright on the table so its edge is even with the opening the saw blade fits into when it’s lowered all the way down. Be careful to avoid the blade's teeth.^{[2]
X
Research source}Then, lower the blade down to the table and move the speed square against the side of the saw blade. Look for a gap at the bottom edge of the speed square. If you see one, it means the saw blade isn’t square and needs to be adjusted.^{[3]
X
Research source}
- If there isn’t a gap and your saw isn’t making even cuts, the problem could be the saw blade itself, an unstable fence, or another problem.
2
Loosen the bevel handle and adjust the blade to contact the speed square. Locate the bevel handle at the back of the saw. Loosen the handle enough to allow you to move the blade around. Hold a speed square upright on the table with its edge lined up with the opening the saw blade fits into. Move the blade until it makes complete contact with and is flush against the speed square to adjust it. Then, tighten the bevel handle to secure it and you’re all set.^{[4]
X
Research source}
- The blade shouldn’t be loose at all. If it is, try tightening the bevel handle some more.

Question 3 of 6:

How do you set the depth on a miter saw?

Adjust the depth stop. Unplug the saw so it doesn’t have any power. Loosen the hex nut on the top of the upper saw arm with a 10 mm wrench. Then use a 5mm hex key wrench to turn the screw counterclockwise if you want to lower it and clockwise if you want to raise it. Lower the blade to the table to check the depth and make any necessary adjustments. Then, tighten the hex nut so it’s secure.^{[5]
X
Research source}
- If the adjustment screw keeps turning when you’re trying to tighten the hex nut, hold it still with the hex key wrench while you tighten the hex nut.
- Keep in mind that miter saws are factory set to a depth that provides the best cutting ability, but the blade can wear down over time and after repeated sharpening. If that happens, you may need to adjust the depth.
- Make sure the blade doesn’t extend more than ¹⁄₄ inch (0.64 cm) below the table insert when you adjust it.^{[6]
  X
  Research source}

Question 4 of 6:

How do you adjust a miter saw fence?

Use a speed square and a level to make sure both fences are even.^{[7]
X
Research source} Make sure the saw is unplugged and loosen the 2 bolts on the left-hand side of the fence with a wrench. Lower the saw blade and place a speed square flat against the fence. Then, adjust the fence until it makes complete contact with the side of the saw blade, and tighten the bolts. Place a 3 ft (0.91 m) level across both fences and adjust the right fence until it’s flush with the left fence and the level is even.^{[8]
X
Research source}
- You adjust the right fence the same way you adjusted the left.
- It’s important that both fences line up with both the saw and each other so your cuts are consistent.

Question 5 of 6:

How do you calibrate a miter saw?

Check the table, fence, blade, and bevel to make sure they’re square. Make sure the saw is unplugged and lay a flat level across the table to look for gaps. If there are, you may need to have the table adjusted at a machine shop. Adjust both the fence and blade using a speed square. Then, tilt the saw to its 45-degree angle and place your speed square against it at a 45-degree angle. If there are any gaps, turn the bevel adjustment bolt, usually located near the back of the saw, until there isn’t a gap.^{[9]
X
Research source}
- If the saw table has major gaps, you may need to replace it.

Question 6 of 6:

How do you cut a 45-degree angle on a miter saw?

Rotate the saw table until it’s set to a 45-degree angle. Press the button or squeeze the handle at the end of the saw table to release it. Turn the saw table until it reaches the 45-degree stop and then release the handle to lock it into place. The saw will then be set to cut at a 45-degree angle.^{[10]
X
Research source}
- The saw has built-in stops and markings so you can easily identify the angle you’re setting it to.

Community Q&A

Question

When my chop saw is set on 0, it is cutting at a slight angle. How do I fix that?

Imtiaz Nabi

Community Answer

It is possible for chop saws to have zero error. You will need to calculate the error first using a woodworking speed squares or something similar to calculate the angle first. After that, adjust the saw slightly off that angle to compensate for the error. This is the best, and easiest solution.
Question

If I move the blade across the wood, it follows my line perfectly, but with the blade running, it moves off to the right away from my line by 3 or 4mm.

imtiaz nabi

Community Answer

Consider clamping your work piece, as sometimes the vibration produced during the job can cause such errors.

Warnings

Always make sure the saw is unplugged before you make any adjustments. Remember to also check your saw's safety manual for more specific information regarding your model.^{[12]
X
Research source}

⧼thumbs_response⧽
Helpful 0 Not Helpful 0