Shop-Made Chamfer Sander for Consistent 45° Edges
Adding a small chamfer is a simple way to soften the sharp edges of a woodworking project. But sanding a consistent chamfer by hand can be tricky. It's easy to change the angle or remove more material in one area than another.
To make the job easier, I built this shop-made chamfer sanding block that maintains a consistent 45° angle while controlling the width of the chamfer.
The secret is a pair of angled runners that guide the sanding block along the edge of the workpiece. One runner is fixed, while the other adjusts to set the chamfer width.
It's a handy tool for creating clean, uniform edges without setting up a router.
How the Chamfer Sanding Block Works
This DIY chamfer sander uses two runners to guide the sanding surface along the corner of a workpiece.
The runners are shaped at 45°, keeping the sanding block at the proper angle as you move it along the edge.
One runner is permanently attached to the block. The other can slide in or out to adjust the width of the chamfer.
Once you've set the desired width, tighten the screws into the threaded inserts to lock the adjustable runner in position.
Then sand along the edge until both runners contact the workpiece.
At that point, the runners prevent the sanding block from removing additional material, helping you create a uniform chamfer from end to end.
Make the 45° Guide Runners
The runners are simple to make from plywood.
Start by tilting the table saw blade to 45° and ripping a strip of plywood to create the angled profile.
Then cut the runners to length.
Glue one runner permanently to the sanding block.
The second runner remains adjustable and is secured with screws that engage threaded inserts in the block.
This arrangement allows you to fine-tune the width of the chamfer without changing the 45° sanding angle.
Add Sandpaper to the Chamfer Sander
The sanding surface is covered with a strip of 1½"-wide, 180-grit adhesive-backed sandpaper.
Apply the sandpaper to the flat portion of the block, as shown in the drawing.
The adhesive holds the abrasive in place, while the adjustable runner helps secure the sandpaper.
When the abrasive wears out, remove the old strip and replace it with fresh sandpaper.
Adjust the Chamfer Width
One of the biggest advantages of this sanding block is that you can control the size of the chamfer.
Loosen the screws holding the adjustable runner and slide it to the desired position.
Then tighten the screws to lock the setting.
The tool can be adjusted to create chamfers up to ¼" wide.
However, I find that it's best suited for smaller chamfers, particularly those around ⅛" wide or less.
For larger chamfers, a handheld router with a chamfer bit is generally a faster and more efficient choice.
Sand Consistent Chamfers by Hand
With the chamfer width set, position the sanding block over the edge of the workpiece.
Move the block along the edge using smooth, even strokes.
The runners keep the sanding surface at a consistent 45° angle, so you don't have to rely on maintaining the angle by hand.
Continue sanding until both runners make contact with the workpiece.
This provides a built-in stopping point that helps prevent over-sanding.
The result is a clean, uniform chamfer that looks consistent along the entire edge.
For small chamfers and final edge preparation, this adjustable chamfer sanding block is a practical alternative to setting up a power tool.
DIY Sanding Blocks: 3 Easy Options for Woodworking
A guided sanding block makes creating consistent chamfers easy, but it's just one of many useful sanding tools you can build for your shop.
Discover three simple DIY sanding blocks made from scrap wood, dowels, and sandpaper. These handy tools make it easier to smooth flat surfaces, ease sharp edges, and sand inside curves.
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