Easy DIY Trim Router Circle Cutting Jig – Part 2

See how to precisely mark and drill the holes for mounting your trim router to the circle cutting jig in Part 2 of this series for how to make the easiest circle cutting jig ever. And it works on any size circle.

This 3-part series takes you step-by-step through creating this circle cut jig.
See the whole series in order here

See it All

Below you will find:

• Video Tutorial
• Materials List
• Written tutorial with photos

Video

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The Easy DIY Trim Router Circle Cutting Jig Part 2

Tutorial

In Part 1 of this series we determined the maximum thickness for our jig wood.

Plus we marked the jig’s overall dimensions.

And we drilled the hole for the router bit.

And then we cut the slot for our variable circle center point.

In Part 2 today we’ll mount the router to the jig.

Remove the router base

TIP: Get a container for those screws!

Once the screws are out, remove the base and place it upside down on the jig wood and square it as much as possible.

Mark the Holes

Mark the holes for the screws.

Besides a pencil, you can also use a nail to scratch the center point.

Remove the router base.

Use a center punch or nail to indent the very center of the holes to make it easier to align your drill bit.

Drill the Screw Holes

I did this part on my drill press. If hand drilling, stay as perpendicular as you can.

Choose your drill bit size.

Because these are machine screws, you’ll want a hole the same size as the screw.

SEE: How to match drill bit to screw size tutorial, but instead of going one size smaller with the bit, keep it the same size.

You can also use the base of the router to check for hole size.

I think my router is using metric screws as a 5/32” bit was a bit too small and the next size up was way too big. I elected to go a little too small.

Drill the 4 holes.

And be as precise as you can.

Countersink the Screw Holes

IMPORTANT!! Be sure to flip the jig board over to drill the countersinks on the backside!!

It’s super important for the screw heads to be below flush with the bottom of the jig.

If you’re using ¼” plywood for the jig, you really can’t drill too far down before going all the way through!

You can use your router base to help determine the size of the countersink bit. Mine was 21/64”.

Be sure the bit is wider than the head of the screw so that it can fit all the way in.

TIP: Go slow and check depth often!!!! And when you resume going deeper, it will only throw out a little dust at a time because you’re not taking much off at a time.

So, keep going slow until you get it.

Mount the Router

Be careful of orientation (ensure the front of the router is facing the top of the jig).

Stand your router on end.

Line up your screw holes with the router.

If any are off, you may be able to simple widen one of the holes a bit by angling a drill bit in it. Or maybe use an Xacto knife to shave a little of the hole on one side.

Be sure to get all 4 screws started before tightening any of them down.

TIP: Don’t over tighten!! There really aren’t many plies of wood left at the bottom of the countersink. You don’t want to over tighten the screws and break through.

When you’ve got them all in, ensure that all 4 screw heads are below the plane of the wood.

Check Router Bit Placement

The last test of your mount is to ensure that the router bit is still centered in the hole you drilled.

If it’s not, then you can turn on the router for a moment to chew away any wood touching.

Just know that if it is way off, you’re slot for the center point of your circle will be off too, and may no longer be centered with the bit.

Next Step

Okay, that’s it for Part 2.

In Part 3 of this series we’ll mount our jig to a scrap piece of plywood and do a test cut of our first circle.

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