Introduction: Spiral Cut Saw Circle Cutter and a *detail Router Adaptor

Intro notes -

For the Redditors in the crowd. Obligatory completed and cause in first photos.

{edit- I had a couple requests. Yes, i can build one for you. PM and we'll work details. For anyone interested in the big purchase or licensing of design, please feel free to contact me. }

I needed a circle cutter for a project I'm working on. I have a Ryobi 18v spiral cut saw, and wanted to make more use out of it. I had previously cut some large circles with the factory Ryobi circle cutter and it was too small and flimsy to cut thru any thickness of wood.

I needed something more stable. For my big project i'm working on I had a need for aluminum and to know how it cut and and drilled and such. So I broke down and bought some .125 2" aluminum bar and was playing with it in the garage. I had cut off a section and had drilled it and tapped a couple holes seeing how things held with various threads. And I'd sat the piece down next the spiral cut and noticed it was about a nice working size for the tool. And inspiration hit. And I started toying with the metal more. I'd ran a hole saw thru it a couple times and had some discs. The reason tell you this, is because some of the design might not make sense if you see the extra hole and markings. I was just playing and the design started falling in place.

Step 1: Aluminum

Materials - 1/8" (.125) Aluminum 2" bar.

This stuff cuts really easy. Use your own common sense.

I was cutting this with standard woodworking saw blades. It will dull your blades quickly if you choose this route.

Use your own common sense when building and working with any materials. I'm not responsible if you're not smart enough to use power tools or anything else. Just saying.

Tools I used.

Radial arm saw


hole saws

drill press

metal files

metal scribes

1/4 drill bit

couple other drills for smaller screws.

and1" belt sander

Step 2: Layouts for Circle Cutter Bar

I could drill the big holes a hole saw, but how was I going to run that long pass down the middle.

I have a friend that has a large drill press with x/y table on it that can handle light milling. Knock knock :)

I laid out the basic plans and taken the piece over for milling. Sorry no pictures there. Forgot my phone.

We drilled most of the material out of the pass and then started running the bit up and down. After we got thru there was plenty of time to use files to smooth out the channel in the center. I had already cut some discs out of the material, lets see what i can do with those.

Step 3: Cutting Discs and Playing With Sanders

I had cut the discs by using a hole saw. I was just playing and had decided to smooth out the jagged edges of the discs. I had noticed that the discs were about the size of the spiral cutter base stand. Hmmm.. Can i size them to drop into the spiral cutter so i jigged up for a spin *balance and broke out the belt sander.

Note, when doing something like this, aluminium dust is very bad for your lungs and your eyes. Always wear dust masks and impact resistant glasses when working with any tools.

Step 4: The Router Base

I wasn't really in photo mode when i was building this.

So sorry for jumping around. All the pictures where 2nd thought.

By this time i've assembled the base. I've installed and tightened the screws and took it for a test run on my work bench just holding the plate flat and sliding. Works remarkably well. Altho it could use some finger holds.

I'm not going to instruct you on how to build. If you're considering this, you should be at little more advanced skill level with tools the assembly is pretty much common engineering.

For safety reason, yeah i know this thing can be dangerous if you're not smart.

Step 5: Putting It All Together. Router and Circle Cutter Joined As One!

Marrying these wasn't easy.

And this type of marriage is only legal in 26 states. Build with caution.

Read the pictures for assembly and function notes.