How to Make Dentil Molding on the Table Saw
Dentil molding is one of those traditional furniture details that looks complicated but is surprisingly easy to make in your own shop.
Characterized by a repeating series of small rectangular blocks separated by evenly spaced openings, dentil molding adds depth, shadow lines, and architectural character to cabinets, bookcases, and other furniture projects.
The design has been used for centuries in architecture and fine furniture. And while it may look like a detail that requires specialized equipment, you can make dentil molding with a dado blade and a simple table saw jig.
In fact, if you've ever cut box joints, you already understand the basic technique.
How Dentil Molding Is Made
Take a close look at dentil molding and you'll notice that it resembles one half of a box joint.
The pattern consists of evenly spaced recesses cut into the edge of a molding blank. The material left between the recesses forms the decorative blocks, or dentils.
Just like a box joint jig, a dentil molding jig uses an indexing key to position the workpiece for a series of repeatable cuts.
But there's one important difference.
With box joints, the fingers and spaces are usually the same width. With dentil molding, you can vary the proportions of the blocks and openings to create a design that complements your project.
Plan the Dentil Molding Pattern
Before building the jig, decide how you want the finished molding to look.
Start by drawing a simple layout showing the width of the blocks and the spaces between them.
The proportions should suit the furniture you're building.
For a small cabinet, narrow blocks and closely spaced openings may look best. A larger bookcase or traditional furniture project may call for a bolder pattern.
It's also important to consider the overall length of the molding.
In most cases, you'll want a full block at each end rather than finishing with a partial dentil.
Planning the pattern ahead of time allows you to adjust the block width and spacing so the finished molding looks balanced.
Once you've settled on the design, you can build the jig to match.
Build a Simple Dentil Molding Jig
The jig consists of two main components: an auxiliary fence attached to the table saw's miter gauge and an indexing key that controls the spacing between cuts.
I used plywood for the auxiliary fence, but MDF is another good choice.
The fence supports the molding blank and provides a place to install the indexing key.
Install the Indexing Key
The indexing key is what makes the jig work.
After each cut, the completed recess fits over the key, positioning the workpiece for the next cut.
This allows you to make a series of evenly spaced dadoes without measuring and marking every opening.
The key should fit the dado snugly enough to position the molding accurately without binding.
Its distance from the dado blade determines the spacing of the pattern.
Because the block width and opening width can be different, it's important to set this distance according to your layout.
Position the Fence on the Miter Gauge
With the indexing key installed, carefully measure the distance between the key and the dado blade.
Position the auxiliary fence on the miter gauge so the spacing matches your planned dentil pattern.
Then secure the fence to the miter gauge.
Before cutting your actual molding, make several test cuts in a scrap piece of the same thickness.
This allows you to verify the width of the openings, the size of the blocks, and the fit of the indexing key.
Make any necessary adjustments before moving on to the finished workpiece.
Cut the Dentil Molding on the Table Saw
Once the jig is set up, cutting the molding is straightforward.
The key is to work through the pattern one cut at a time, using the indexing key to maintain consistent spacing.
Step 1: Make the First Cut
Start by positioning the molding blank against the indexing key as shown in the drawing.
This establishes the location of the first recess while leaving a full block at the end of the molding.
With the workpiece supported against the auxiliary fence, make the first dado cut.
Step 2: Index the Workpiece
After making the first cut, turn off the saw and allow the blade to stop before repositioning the workpiece.
Move the molding blank so the recess you just cut fits over the indexing key.
This automatically positions the workpiece for the next cut.
Make the next dado, then repeat the process.
Each completed recess becomes the reference for the following cut.
Step 3: Complete the Pattern
Continue indexing the molding blank and making successive cuts until the pattern is complete.
The result is a row of evenly spaced decorative blocks.
If you planned the layout carefully, the molding will finish with a full block at each end.
Tips for Making Accurate Dentil Molding
A few details will help you get better results from the jig.
Start with a straight, square molding blank. Consistent thickness and a straight reference edge help the jig produce accurate, repeatable cuts.
Make test cuts first. A scrap piece lets you confirm the proportions and indexing setup before cutting your finished molding.
Keep the indexing key snug. A loose-fitting key can allow the workpiece to shift, resulting in uneven spacing.
Use a sharp dado blade. Clean cuts produce crisp edges and reduce the amount of sanding required.
Support the workpiece. Keep the molding blank firmly against the auxiliary fence throughout each cut. Use an appropriate hold-down or workpiece-control method that keeps your hands safely away from the blade.
Also, make sure your table saw is approved for dado blade use and that the jig provides adequate support throughout the operation.
Add a Traditional Detail to Your Next Furniture Project
Dentil molding is a great example of how a simple shop-made jig can produce an impressive decorative detail.
With a little time spent planning the proportions and setting up the indexing key, you can create consistent molding for cabinets, bookcases, and traditional furniture.
And once you've made the jig, it's easy to experiment with different block widths and spacing to suit future projects.
It's a straightforward table saw technique that can add a lot of character to your woodworking.
Woodpeckers Ultra-Shear Grooving Blades Review
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Take a closer look at these specialty blades and see how they can improve your woodworking joinery.
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