In this blog post, I will be sharing how to make a router circle jig for a multi-purpose router base that I previously built. A multi-purpose router jig is a tool used in woodworking with a trim router that can perform a wide range of tasks such as cutting dados, grooves, rabbets, mortises, flattening wooden surfaces, and even making homemade T-tracks. One of the things that make this jig particularly useful is its versatility.
When it comes to cutting circles in wood, there are several tools you can use such as a jigsaw, a circular saw, or a bandsaw. However, my preferred tool for this task is a router. The results are precise, and the edges come out clean. Additionally, you can easily adjust the diameter of the circle you want to cut, making it a great choice for both small and large circles.
There are two ways to cut a circle with the multi-function router jig:
- You can attach an additional accessory to the multi-purpose router base using T-nuts. However, this method is limited in terms of the diameter of the circle it can cut, and should only be used for small diameters.
- You can attach a prolonged arm to the multi-purpose router base. This method allows you to adjust the diameter of the circle you want to cut with an embedded scale ruler. The length of the arm determines the maximum diameter of the circle you can cut.
The benefits of the circle jig addon are that you will not need an additional standalone circle-cutting jig, it can be used to cut both small and large circles, and you can cut circles of an exact diameter using the embedded scale ruler. Moreover, it can be used with multiple different trim routers.
To make the route circle jig, you will need a plywood and MDF desk, which are easily available at any hardware store. These materials are strong and durable, making them an excellent choice for making woodworking jigs.
Keep reading to find out how to make a router circle jig for a multi-function router base, and how to use it.
DIY Router Circle Jig for a Router Base Video
If you want to see how it is done, watch the video below for a step-by-step guide on how to make a router circle jig addon for a multi-purpose router jig.
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Table of Contents
- Circle Jig for Router Video
- The Material you will need
- General Questions
- What are the benefits of a DIY router circle jig?
- What type of router bit should I use to cut circles with my router jig?
- How to Make a Router Circle Jig Addon for a Multi-Function Router Base
- Step 1: Prepare the router base
- Step 2: Make the Circle Extendable Arm
- Step 3: Make the Slider
- Step 4: Attach the Circle Arm to the Base
- Step 5: Attach the Self-adhesive Scale Ruler
- How to Cut a Circle in Wood with a Router Circle Jig Addon
- Woodworking Jigs Used
*Safety is your responsibility. Make sure you know what you’re doing and take all necessary safety precautions while working with power tools. Safety comes first!
What you'll need to make a Router Circle Cutting Jig Addon
Multi-function Router Base
How to make a Multi-Function Router Base
Circle Jig Addon
Plywood 1x – 290 mm x 60 mm x 6,5 mm
MDF 1x – 250 mm x 60 mm x 5 mm
Check all the Tools I Use
Tools:
Trim Router – https://amzn.to/3HbQcOg
Corded Hand Drill / Drill Press – https://amzn.to/3NSA3Bo
Hand Drill – https://amzn.to/3HqLEnH
Table Saw / Proxxon Mini Table Saw – https://amzn.to/47mWiGf
Japanese Ryoba Saw – https://amzn.to/48if4Qz
One Hand Clamps – https://amzn.to/48jGxkZ
Spring Clamps – https://amzn.to/41Nuh9D
Narex Chisels – https://amzn.to/3tHNJrT
Machinist Square / Speed Square
Other:
Wood Glue – https://amzn.to/48ltKhJ
Epoxy – https://amzn.to/3tJ5R4L
Sandpaper Sheets – https://amzn.to/41OMx2p
Drill bits – 6mm – https://amzn.to/48Kaaf7
Router bits – 6mm/4mm – https://amzn.to/3NQNDVX
Self-adhesive scale ruler – https://amzn.to/3TTjGZb
Aluminum bar, Brass rod 4mm – https://amzn.to/47s0eWc
Wing nuts, Square nuts, Washers, M6 bolts – https://amzn.to/41PodgQ
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What are the benefits of a DIY router circle jig?
- Increased precision: A router circle jig allows you to cut precise circles of varying sizes with ease. This precision is especially helpful for projects that require a specific size or shape.
- Clean edges: The router’s blade is designed to make smooth, clean cuts that leave the edges of the circle looking professional and polished. This makes it a great tool for woodworking projects that require clean and precise edges.
- Cost-effective: Making your own router circle jig can save you money compared to buying a pre-made one from a shop. With readily available materials like plywood and MDF, you can create a high-quality jig that is customized to your needs.
- Versatility: With a router circle jig, you can cut circles of different sizes. You can use it to make decorative wooden pieces, cut holes in panels or boards, or create circular patterns.
- Accuracy: The embedded scale ruler on the jig ensures that you can set the diameter of the circle you want to cut with precision. This means that you can create circles that are perfectly round and of the exact size that you need.
What type of router bit should I use to cut circles with my router jig?
When it comes to cutting circles with a router jig, the type of router bit you use can make a big difference. Here are two types of router bits that are commonly used for this purpose:
- Straight bits: These bits have a flat bottom and are perfect for cutting circles with a consistent diameter. They come in a range of sizes, so you can easily choose the right one for your project. The benefits of using straight bits are their affordability, versatility, and precision. You can get a good quality straight bit at a reasonable price, and it can be used for a wide variety of other woodworking tasks, too.
- Spiral bits: Spiral router bits are designed to remove material more quickly and smoothly than straight bits. They have a spiraling flute that helps to eject chips and keep the bit cool during use. Spiral bits can be a good choice for cutting circles in thicker materials or when you need to make a lot of cuts quickly. The benefits of using spiral bits are their speed, efficiency, and precision. While spiral bits can be more expensive than straight bits, they can save you time and effort in the long run, making them a good investment for serious woodworkers.
Let's start building!
As previously discussed, this is an add-on for a multi-purpose router base. It is assumed that you have already constructed the multi-purpose router jig.
Making a circle-cutting jig entails making an extendable arm, which consists of a t-track, an adjustable slider, and an embedded scale ruler.
Router circle jig properties:
- Material: Baltic birch plywood, MDF, self-adhesive scale ruler
- Total dimensions: 290mm x 60mm x 11.5mm (11.42 inches x 2.36 inches x 0.45 inches)
- Total dimensions with router base: 405mm x 140mm x 140mm (15.94 inches x 5.51 inches x 5.51 inches)
- Circle diameter: from 40mm to 420mm (1.57 inches to 16.54 inches)
This woodworking project is recommended for those with some experience in woodworking.
NOTE: The attachment to the multi-purpose router base is the most crucial aspect of this project. The joint experiences a lot of pressure while cutting a circle; thus, ensure that it is tightly secured.
How to Make a Router Circle Jig Addon for a Multi-Function Router Base
To begin building the circle jig, the first step is to disassemble all the parts of the multi-function router jig, leaving only the router base.
Step 1: Prepare the router base
To prepare the base for the circle-cutting jig, start by cutting out the plywood layer from the center of the base – do not throw it away. The cut-out width should be 5 cm, and it should be on the front part of the router base where the base is wider. You can use a Ryoba saw for this step, which will ensure clean and precise cuts.
NOTE: When building the multi-function router base, it’s best to avoid gluing the plywood and MDF layers on the front part of the base. This will make it much easier to make the cut-out and separate the two layers.
Turn the router base upside down and use a machinist square and ruler marking gauge to mark the position of the screws and nuts. Then, drill a 6mm hole and cut a square hole around the hole to insert the nuts.
When fixing the nut in the hole, use epoxy and make sure the nut is flush or just slightly sunk into the surface of the base. The nut should not protrude.
Step 2: Make the Circle Extendable Arm
To begin making the arm of the circle jig, start by cutting a piece of plywood and an MDF piece. These two pieces will be attached to the router base to form the arm of the circle jig.
The dimensions of the plywood piece are 290mm x 60mm x 6.5mm (11.4 inches by 2.4 inches by 0.26 inches), and the dimensions of the MDF piece are 250mm x 60mm x 5mm (9.8 inches by 2.4 inches by 0.2 inches). There are multiple ways to cut these strips, but I personally used a Proxxon mini table saw with a fence and crosscut sled.
To make a t-track in which the runner will move, you need to cut a slot in both the plywood and MDF strips. The slot in the MDF strip should be 15mm, while the slot in the plywood strip should be 6mm.
There are various ways to cut slots in wood – you can use a jigsaw, a coping saw, or a circular saw. My preferred method is to use a router dado jig.
Glue the plywood and MDF strips together. Ensure that no glue is present in the slot. If any glue is present, clean it thoroughly.
Once the glue has cured, cut a shallow slot on the top of the arm for the self-adhesive scale ruler. The slot should be just deep enough for the ruler to sit flush with the top of the arm.
Note, that the width of the arm is 60mm, while the hole on the router base is only 50mm. To fit the arm onto the base, you’ll need to cut 5mm from each side. I used a combination of a table saw and a hand saw to do this.
NOTE: Use sandpaper to get a nice fit between the arm and the base.
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Step 3: Make the Slider
For the slider, it is better to start with a piece of plywood with dimensions wider than the final product. The final dimensions of the slider should be 120mm x 15mm x 5mm.
The slider is responsible for running in the t-track. It contains a mechanism that sets the diameter of the circle and a pivoting pin, which is used to cut the circle.
To create the fixing mechanism and the pivoting pin, you need to cut three holes in the plywood piece. The outer holes have a diameter of 4mm, while the inner hole has a diameter of 6mm. Cut a hexagon shape around the inner hole to accommodate the bolt head. After finishing the holes, cut the plywood piece to its final size.
Next, apply epoxy to the center hole and insert a bolt, ensuring it is flush with the surface. Then, apply epoxy to the outer hole and insert a brass pin, ensuring that the bolt and pin face opposite directions.
NOTE: The brass pin protrudes around 4mm from the surface of the plywood piece.
Insert the slider into the t-track, and use epoxy to secure the pin in the last hole. This pin will help you read the values on the scale ruler and adjust the circle diameter. Keep in mind that a simple pin will work just as well as a fancy one, so do not worry too much about making it too elaborate. 😉
Step 4: Attach the Circle Arm to the Base
First, cut a 15mm slot in the MDF layer of the router base to allow the slider to move closer to the router bit, enabling you to cut smaller circles.
Next, place the circle arm onto the router base and secure it with screws and washers. At this point, the arm should be firmly attached to the router base, and the slider should move smoothly along the track.
Step 5: Attach the Self-adhesive Scale Ruler
Note that this jig should be used with one size router bit only. I am using it with a 6mm router bit.
Set an arbitrary diameter on the arm and cut out a circle. Measure the diameter from the cut material (not from the circle) and tape the self-adhesive scale ruler to the right position on the circle arm. In this case, when setting the circle diameter, you will know you are cutting the outer diameter. (If you would prefer you can set the scale ruler for the inner diameter of the circle).
If you need to use your router base for other projects, you can easily detach the circle arm from it. Simply remove the screws and washers that hold the arm in place. Once you have removed the arm, you can bridge the hole on the router base with the cutout piece. This will ensure that the base is level and smooth, and ready for your next project.
How to Cut a Circle in Wood with a Router Circle Jig Addon
If you want to cut a perfect circle in wood, the router circle jig addon is a great tool to have. Here are the steps to follow:
- Attach the extendable router circle cutting jig to the multi-purpose router base with screws.
- Set the diameter of the circle using the scale ruler on the arm and lock the pivoting pin in position.
- Drill a hole in the workpiece and insert the pivoting pin.
- Start the router and slowly deepen the router bit in the workpiece.
- Cut the circle by turning the router jig around the pivoting point.
- Once the circle is cut, wait until the router is fully stopped before removing the circle jig.
TIPS
- Don’t cut too much material at once: When using a router circle jig, it’s important to take your time and make multiple shallow passes instead of trying to cut through the entire thickness of the material in one go. This helps to avoid putting too much pressure on the router bit, which can cause it to break or leave burn marks on the wood.
- Use a mat below the workpiece: Placing a mat or other protective layer underneath your workpiece can help to prevent damage to your worktable or work surface as you cut the circle. T
- Use double-sided tape to fix the circle while cutting: To ensure that your circle stays in place while you’re cutting, consider using double-sided tape to secure it to the workpiece. This can help to prevent the circle from moving or shifting as you cut, which can result in a more precise and accurate cut.
Conclusion
In conclusion, the router circle cutting jig is a versatile and affordable addition to any woodworking shop. Utilizing a multi-purpose router base in combination with the router circle jig will let you cut circles of various sizes with precision and accuracy. So, get your tools, and let’s get started!
