Slots show up all over the woodworking shop. They're especially useful in jigs and fixtures, where a bolt or other fastener needs to slide along a controlled path to provide adjustment.
Fortunately, you don't need a special router bit or complicated jig to make them.
With an ordinary straight bit, two starter holes, and a pair of stop blocks, your router table can cut clean, accurately positioned slots with very little setup.
Start with the Slot Layout
Before heading to the router table, lay out the position and length of the slot on the workpiece. Then drill a starter hole at each end of the slot.
These holes do more than establish the rounded ends of the finished slot. They also provide convenient reference points for setting the router table fence and positioning the stop blocks.
The hole diameter should correspond to the straight bit you're using to rout the slot.
Set the Router Table Fence
Install the straight bit in the router table.
With the router off, position one of the starter holes directly over the bit. Orient the workpiece in the same direction it will travel while routing the slot.
Slide the router table fence against the edge of the workpiece and lock it in place.
The fence now establishes the path of the cut and keeps the slot parallel to the edge of the workpiece.
Set the First Stop Block
Keep the first starter hole positioned over the router bit.
Now place a stop block against the edge of the workpiece that's farthest from the bit and secure the stop to the router table fence.
This stop establishes one end of the workpiece's travel.
Set the Second Stop Block
Next, reposition the workpiece so the second starter hole is centered over the router bit.
Place another stop block against the opposite end of the workpiece and secure it.
Now the workpiece is trapped between the two stops, and its travel corresponds to the length of the slot.
It's a simple setup, but that's what makes the technique so useful. The holes themselves establish the beginning and end of the router cut, eliminating the need to measure the stop locations separately.
Rout the Slot in Multiple Passes
Don't try to rout through the full thickness of the workpiece in one pass.
Instead, remove the material in stages. The technique shown here uses cuts of about 1/4" per pass.
Brace the workpiece against one stop and carefully pivot it down over the spinning bit using the starter hole as the entry point. With the workpiece firmly against the fence, slide it smoothly until it contacts the opposite stop.
Turn off the router and wait for the bit to stop before making adjustments. Raise the bit for the next cut and repeat the process until the slot reaches the required depth or passes through the workpiece.
Woodsmith Tip: Let the Holes Do the Setup Work. The beauty of this method is that the two starter holes perform three jobs. They establish the ends of the finished slot, provide entry points for the router bit, and give you exact references for positioning the stop blocks.
Why Use Stop Blocks?
You could try routing a slot by watching layout lines, but stop blocks make the operation much more controlled and repeatable.
Once they're positioned, the workpiece can travel only as far as the slot requires. This is particularly helpful when you're making several identical parts for a jig or fixture.
The fence controls the slot from side to side, while the two stops control its length.
A Useful Router Table Technique for Jigs & Fixtures
Once you learn this setup, you'll find plenty of uses for it.
Adjustable fences, sliding stops, hold-downs, shop-made tool accessories, and other woodworking jigs often rely on bolts traveling through slots. Being able to make those slots accurately means you can build adjustment directly into your shop-made accessories.
And because the setup relies on a straight bit, a fence, and a couple of scrapwood stops, you can put the technique to work without building a dedicated jig.
Put Your Router Table Skills to Work
Routed slots are an easy way to add adjustment to shop-made accessories. Explore our collection of woodworking jigs and fixtures for the table saw, router, drill press, bandsaw, workbench, and more — all designed to help you work more accurately and make your time in the shop more productive.
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