I need to miter a new crown molding to an existing outside crown molding.

Similar to this stock photo:

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My old school crown molding looks like this:

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  1. Can I assume the angle is 45 degrees?

  2. Is this a compound miter? On my chop saw I need to cut the piece upside-down because it only bends one way on the vertical. Is the base angle 45 and the vertical tilt angle 45?

My scrap cut didn't look right and this special order crown is expensive.

EDIT: Pictures of my saw enter image description here

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  • 1
    This is a compound miter shoot a picture of the saw yiu are using
    – Kris
    Jul 8, 2019 at 2:20
  • 3
    If your saw doesn't flop both ways, you might consider building a mini sled that holds the crown upside down at its spring angle (45 or whatever). Then the only angle you need to worry about is the ~45 inside and outsides. See blocklayer.com/crown-molding.aspx Jul 8, 2019 at 3:11
  • 2
    Get some cheap crown molding with the same angle and try cuts before you use it on the expensive stuff. Do you have a table saw? You could make some test 45-45 "molding" from scraps and use it to make test cuts. Jul 8, 2019 at 11:46
  • 2
    Agree with above comments. Never assume the angle of the moulding, and never assume the angle of the corner is 90 degrees. Definitely use a mock-up or tests piece to get the angles right. Especially when trying to match an existing cut, it's going to take trial and error.
    – JPhi1618
    Jul 8, 2019 at 14:50
  • 3
    Making these cuts is very confusing unless you do it a lot. Look up a video on it and make practice cuts with cheap molding. With your saw you could possibly cut the molding flat with compound cuts (miter and bevel) or you could just use the miter (bevel 0) and stand the molding in a right angle rack. The right side of your saw has holes in the back for attaching a higher fence (you'd use plywood) that would allow you to stand the molding at the angle it will be on the wall. See here dewalt.com/dewalt-dna/featured-articles/… Jul 9, 2019 at 15:28

2 Answers 2


To answer your specific questions, you shouldn't assume spring angle is 45 degrees. Put a framing square on the flats of the crown and you'll know if it's symmetrical or 38/52.

To cut this flat, your bevel and miter angles are somewhere in the 30 degree range. See the link below to figure the actual numbers.

Since your saw doesn't flop both ways, you might consider building a mini sled that holds the crown upside down at its spring angle (45 or whatever). Then the only angle you need to worry about is the ~45 inside and outsides. See tutorial on crown angles

(I'm not saying you need to do this; it's just that only cutting crown with only one direction of bevel will force you to cut upside down occasionally, which is bad for tearout and relatively confusing sometimes.)

Mini sled... mine:

basic sled

(Not shown: the upright of the sled is bolted to the fence of the saw so it won't move. Clamps might be an option, but they'll probably get in the way.

Terrible picture angle, but set the crown upside down with the flats aligned with the base and the fence:

crown up against fence

Note the pencil line that indicates where the crown is supposed to sit on the base. Hole in the base so I can see my miter angles.

Finally, tack a straight bit of something onto the pencil line on the sled to keep the crown from slipping out of angle:

attach a stop to the base of the sled

Last notes, if you're meeting up to an existing piece, they may have felt forced to tweak the spring angle just a teensy bit, which will make it hard to match perfectly. Do as much as you can to have extra length while you're whittling away at a perfect fit. Don't expect corners to be perfect 90 degrees, either. If it's paint grade, there's a lot of forgiveness to be found in sandpaper and spackle.


Thanks to everyone for the great ideas which led me to "my" solution.

I bought the Kreg Crown-Pro and although a great tool it lifts the molding to high and my saw can't make the complete cut.

Not saying it's bad, just didn't work for me.

However, the Kreg directions (not the tool) were the key for me.

I carefully clamped the molding to the saw upside down. I used the Kreg methodology to find the angle to cut.

It came out better than I thought.

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