Zero Clearance Miter Saw Fence Homemade Machines & Jigs

For cutting trim and small pieces on the miter saw, it’s a good idea to make a secondary fence that will fit over the stock one and provide zero clearance slots for the blade. This allows you to make cuts that are more accurate and safer, since the work piece can’t be pulled into the large gap that all of these saws have.
I’ve been meaning to make for for a while, and with some projects coming up that would really benefit from having one, I decided now was the time.

To start, I cut two pieces of 3/4″ plywood into strips that are 48″ long. The size of the strips depends upon the size of the saw you will put them on. For me, the base was 7″ wide and the upright fence was 4″ wide.
Here I’m spreading some glue to join the two strips together:

Then a 2″ brad in each end to tack it in place:

To avoid cutting into the nails and screws, I carefully lay out where the blade will cut. Unfortunately, as seen in the video, careful layout is only good if you actually follow it!

To help reinforce the joint and clamp it while the glue dries, 1-1/2″ screws are driven:

The first cut is 90 degrees at the centre of the fence. I’ve locked the slide on my saw to stop it from cutting out any further. The loss of cutting capacity is not an issue, as this fence will only be used for smaller stock, like thin trim and molding.

To lock the secondary fence in position on the miter saw station, 1/2″ holes are drilled at each location (45 degrees left, 90 degrees and 45 degrees right) for alignment pins made from 1/2″ dowels:

Cutting the dowels for the fence is a good example of what this fence is meant for – safely cutting thinner stock.

When I need it, it’s just a matter of putting it in place. The dowels will correctly position it in the exact location for the cut:

And when it’s not needed, it can be quickly removed and stored beside the saw station.

I made a video of the build and demonstrate how it works: