Cut Crown Molding With Just a Miter Box

Do you struggle to understand the fundamentals of cutting the perfect crown molding corners (inside or outside)?

Have you watched instructional video after instructional video trying to learn coping (or getting discouraged because of so many different tactics to try) just to wind up either more confused or buying expensive tools that will supposedly make your life easier?

Or maybe you simply only have a basic miter box and need to know IF cutting crown molding is even possible...

This was me on my first (and, thus far, only) time doing crown molding.

I heard from everyone how a cheap and "easy" fix to making your house look more lux is to add some molding. Did you see that word? "Easy." Ha! Apparently the authors of such articles never cut their own crown molding! Crown molding is anything but "easy."

However, out of hundreds of crown molding videos and tutorials, I finally found a trick that ACTUALLY WORKS and made it simple for me to understand exactly how to cut the corners without all the confusing ways to turn it and this and that. So I feel obliged to share this exciting AND SUPER EASY trick with you!

So can you cut crown molding with just a miter box? YES! :) And I'm going to show you how!

P.S. I do NOT profess to be a professional or a carpenter of any kind (and my work may show this), but I believe in spreading the helpful knowledge I learn to other noobs like me because even if it's not perfect, it's better than never trying in the first place. :)

Crown Molding of your choice (aka crown "moulding" if you're not American)

Simple miter box with miter hand saw (or you can use whatever tools you have on hand that you prefer, obviously some tools really will make your life easier when cutting crown molding, so I'm not knocking them. I just didn't have them personally)

Finishing nails and Hammer (if you don't have a wonderful nail gun, like I don't)

Caulk

Measuring Tape, Pen/Pencil

OPTIONAL: painter's tape

OPTIONAL: clamps

OPTIONAL: Liquid Nails (to doubly secure the pieces in place)

I added crown molding to the tops of my "built-in" bookcases (they're a work in progress). So to start the process (and give the molding something to nail into), I added 1x2 pieces of scrap wood to the corners, middle, and ends of all the places the crown molding would nail into. It's important to make these sit perfectly flush with the edge of the bookshelf edges.

Mark the "Top" and the "Bottom" of the molding on the FRONT of the molding.

Believe me, THIS IS NECESSARY! It avoids confusion later about what end you have up. And you'll be painting the molding afterwards anyways, so writing on it will be just fine.

Basically, the Bottom of the crown molding has the wider flat base than the top (as seen in the pictures, I'm pointing to the BOTTOM of the molding).

Measure your first side that needs to be covered in crown molding.

This measurement will be the length of the BOTTOM of the molding when it's applied to the item or wall that you're doing. I say that because on outer corners the top of the molding will be longer than the bottom of the molding and therefore this measurement won't apply to the top but only to the bottom.

Don't forget to DOUBLE CHECK your marked line on the molding BEFORE cutting it. Always measure twice, cut once!

So here's the simple and EASY trick I learned so I could keep everything straight in my mind when cutting the corner angles...

OUTER CORNERS = LONGER TOP

INNER CORNERS = LONGER BOTTOM

I heard one guy say this to remember which is which: "You don't want your daughter going OUT with a short TOP" so she needs a LONGER TOP to go OUT!

What does this mean? When figuring out which 45 degree angle to cut on, remember that if it's an outer corner you're working on, the Top of the molding needs to be longer than the bottom, and vice versa for inner corners.

When you get to a single piece that requires an outer angle on one end and an inner angle on the other end, this trick makes it easy to figure out which way to cut for both sides. Just take each side of the single piece as it's own thought, and with this trick you'll NEVER forget or confuse which way to cut it!

Simple idea right? Let's put it into action...

These pictures demonstrate how to hold the molding in the miter box (flipped upside down and the BOTTOM edge sitting flush against the miter box). Now it's ready to cut.

IMPORTANT NOTE: Be sure to hold it extremely secure in this position to get the best results. Using clamps here will definitely help.

So just remember, for EVERY cut you do, you'll follow the basic idea of:
FLIP THE MOLDING OVER (so the "bottom" of the front of the molding is facing up), PRESS THAT BOTTOM UNDERSIDE FLUSH AGAINST THE MITER BOX, AND HOLD IT THERE WHILE YOU MAKE THE 45 DEGREE CUT.

Note: If your molding is too tall for the miter box, simply add a thin piece of wood behind it (such as a 1x4) so it sits flush against that while cutting. You can still reuse this piece once it's cut into at 45 degrees on both sides because then it will have slits matching those of your miter box, and it will be like an extension of your miter box.

First of all, we have to use the trick to answer the question: what is going to be longer for an inner corner? The BOTTOM right? So while the molding is flipped over and pressed against the miter box, simply cut one piece on the right side 45 degree angle, then cut the next piece that fits to it at the left side 45 degree angle. Now you have two pieces that fit together on an inside angle.

As seen in the first picture above, I cut the BOTTOM longer than the top (I'm using the RIGHT side of the cut piece)! The bottom of the molding (which is the top edge in the picture) is LONGER than the top of the molding (which is the bottom edge in the picture). This will make an INNER corner piece.

No coping, no confusion, no chaos.

For an outside corner, you're still going to cut one 45 degree angle from the left side of the miter box and one from the right side (whichever you do first is dependent on what side of a corner you're going around, the right or the left corner), but this time you will make the what longer? The TOP right!?

So start with the process of flipping over the molding and pressing it flush against your miter box, but then just make sure that both cuts have the TOP of the molding LONGER.

NOTE: In the above pictures, I'm using the LEFT side of the cut piece (2nd picture) as my outside corner piece. The 3rd picture shows the opposite side that will meet up with the first piece to make a 90 degree outside corner.

Optional Note: You can use painter's tape to help hold it altogether before and after nailing the trim on (especially helpful if you are waiting for glue or caulk to dry or if you want to keep the corner pieces flush against each other while you nail it in).

After you cut and nail your pieces in place, use caulk to fill in any mess ups or gaps and to make a seamless finish between where the bookshelf or wall ends and the crown molding begins.

TIP: smoothing the caulk with wet fingers after it's applied will get all the excess caulk off and will make the caulk ultra smooth for a clean finish.

I am still working on finishing the crown molding on my bookshelves, but it's a work in progress. Obviously, cutting crown molding is still a lot of work and can prove to be very (no, EXTREMELY) frustrating!

BUT, with this simple trick, maybe it can take a little bit of your burden off your shoulders?

Remember, there WILL BE user error for a lot (if not all) of the crown molding mistakes, BUT just keep at it! YOU CAN DO IT IF YOU DON'T GIVE UP!