Making your own zero-clearance table saw inserts is a simple and inexpensive way to get better support around the blade. But there's a problem you may run into with some table saws.
Even with the blade lowered completely, the teeth may still project high enough that an uncut insert blank can't sit in the throat opening.
If your saw has this problem, there's an easy workaround: temporarily raise the insert with a hardboard spacer.
Make a Hardboard Spacer
Start with a piece of hardboard sized to fit in the table saw's insert opening.
The spacer only needs to be thick enough to raise the zero-clearance blank above the teeth of the fully lowered saw blade.
Next, use a jig saw to cut an oversized blade-clearance slot through the spacer.
This slot doesn't need to fit the blade closely. Its only purpose is to provide clearance around the blade while the spacer supports the insert blank above it.
WOODSMITH TIP: Use Only the Thickness You Need. The spacer isn't intended to become part of the finished insert. Make it only thick enough to provide clearance between the lowered blade and the underside of the blank.
Position the Insert Blank
Lower the saw blade completely and place the hardboard spacer in the table opening. Set the new zero-clearance insert blank on top of the spacer.
Then clamp the blank securely in place so it can't shift or lift while you're establishing the blade slot.
At this point, the spacer has raised the blank enough to clear the blade teeth.
Cut the Initial Blade Slot
With the insert blank securely clamped, turn on the saw.
Slowly raise the blade through the blank to create the initial slot.
Once the slot has been established, shut off the saw and wait for the blade to stop completely before removing the clamp, insert, and spacer.
The insert now has enough blade clearance to continue fitting and setting it up normally.
A Simple Solution to an Unusual Problem
Most table saws may not require this extra step. But if your blade won't retract far enough to install an uncut zero-clearance insert, there's no need to complicate the insert itself.
A scrap of hardboard and an oversized blade slot create a simple temporary spacer that gets the blank above the blade long enough to establish the initial kerf.
And once you've made the spacer, keep it with your extra insert blanks. It'll be ready to use the next time you make a zero-clearance insert.
Build the Complete Insert from Start to Finish
Now that you've solved the blade-clearance problem, see how to make a complete zero-clearance table saw insert. Learn how to use the factory insert as a template, shape the blank, add a retainer and leveling adjustments, and create a blade-matched opening for cleaner table saw cuts.
BUILD A ZERO-CLEARANCE INSERT → Make Your Own Zero-Clearance Insert
