Tuning up your miter saw for perfect cuts is a process worth understanding. All it takes is a few miter saw adjustments from time to time to make sure your 90s are true, both horizontally and vertically.
While the various brands of miter saws have their own specifics on how to make adjustments, they are all pretty much the same.
There are 2 different adjustments you’ll be making for your miter saw.
Horizontal Adjustment – The Fence: You’ll either have a 1 or a 2 piece fence, with bolts holding it down on both sides of the blade. There are probably 4 bolts total securing the fence.
Vertical Adjustment – The Bevel Stop: You’ll likely have adjustable hard stops on the bevel action to make the saw stop right at 90 degrees perpindicular to the cut bed.
Here’s a helpful video that lays out these 2 steps of the process pretty good:
Keep reading to learn how you can make these adjustments to your miter saw for perfecting your cuts.
Miter Saw Adjustments For a Perfect Horizontal 90 Degree Cut
To begin this process, make sure your miter adjustment is set in the factory detent for a straight 90-degree crosscut. This is the position we want to have a perfect 90, and by doing so, the remaining factory detents will be accurate.
Prepping the Fence
If your miter saw has a solid 1-piece fence, you’ll want to loosen 3 bolts and leave the bolt all the way to the left snug. This will be the pivot point for swinging the rest of the fence either forward or back.
If yours has a 2-piece fence, loosen the same 3 bolts. You’ll just push the right fence back out of the way and make your initial adjustments on the left fence.
Small taps make small adjustments.
You can use a rubber mallet or a block of wood to tap the fence to make fine adjustments. If you push on it, you could make the fence flex, and you’ll probably move it too much.
First, align with your square
Now you want to lock the blade down into the lowest position and slide it all the way back (if it’s a sliding saw).
Place your square against the fence, and slide it over until it touches the blade. Make sure it’s not getting against the teeth of the blade though, this will mess up your reading.
Make small adjustments to your fence and retest with the square. Do this until you get it as close as you can to perfect. Tighten down the 2nd bolt to hold it in place. Just make it snug, as you may have to loosen and make more adjustments in a minute.
Fine Tune With Test Cuts
Take a piece of scrap wood that has good straight edges. Using a twisted, bowed or warped board here can mess up your miter saw adjustments.
Hold the piece against the fence like normal and cut off just the edge of the scrap piece. Then check the cut for square.
You’ll either see a gap at the front or back of the cut, or it will be perfect. Depending on what you see, you’ll be able to determine which way the fence needs to be adjusted.
Now loosen that second bolt, and tap the fence to make small adjustments, then retest with a new cut.
Keep doing this until you get a perfectly square cut.
Tighten the fence back up
Now you can really tighten down the 1st 2 bolts. Make another test cut to double-check that you didn’t make the fence move while tightening.
If it still holds a true 90, then tighten the 2 bolts on the right fence.
If you have a 2 piece fence, just hold a straight edge against the left fence and then pull the right fence against the straight edge. Hold it in place and tighten the right 2 bolts.
Make a final test cut to make sure everything has remained perfect while you tightened all the bolts.
Miter Saw Adjustments For A Perfect 90 Degree Vertical
Make a cut to test for square
Hold your scrap wood vertically against the fence and make a cut at the end of the board.
Now holding your square against the base of the board (the side that was against the cut bed), check the cut for 90 degrees.
Fine Tune Adjustments To Your Bevel Stop
By adjusting the bevel stop adjustment nuts on your miter saw, you can fine-tune the vertical cut angle.
Make small adjustments and re-check for square each time, until you get this as close to a perfect 90 as you can get.
Wrapping It Up
Once you’ve made these miter saw adjustments, you should be able to trust the factory common-angle detents to be accurate. This means, for example, your detent stop for a 45-degree miter should be dead-on accurate since you’ve got your fence adjusted perfectly at the 90-degree detent.
With your saw set up for perfection, you can try out a cool little project that really tests the accuracy of your miter cuts: my detailed walk-thru with pictures on How To Build A Picture Frame.
Please leave me a comment below if you have any questions or comments about making miter saw adjustments for perfect cuts.