top of page

Creating a Unique Speaker with the Bosch GCM-18V 216 Mitre Saw: A Step-by-Step Guide

If you're a woodworking enthusiast, you know that there's nothing quite like creating something with your own two hands. Whether it's a piece of furniture, a decorative object, or a functional gadget, the sense of accomplishment that comes from making something from scratch is hard to beat.

In this blog post, we're going to take a look at how to make a mobile wooden speaker using the Bosch BitTurbo GCM-18V 216 cordless mitre saw. This powerful tool is a top choice for woodworkers and DIY enthusiasts alike, thanks to its impressive power, precision, and versatility.

I was recently selected to review Bosch's new GCM-18V 216 mitre saw as part of their BitTurbo tool test program. As a workshop enthusiast, I was excited to try out this new tool from Bosch, as I have had good experiences with their older tools such as jigsaws and circular saws in the past.

I have reviewed mitre saws on my YouTube channel before for Evolution Power Tools, and I always try to give honest and thorough reviews of the products that are sent to me. I believe it is important to be transparent and fair when it comes to the price and performance of these types of tools.

However, for this particular review, I wanted to do something a little different. Bosch had requested a review of the saw that was between 30 seconds and 5 minutes in length, but I thought it would be more engaging and informative to demonstrate the full capabilities of the saw in action. I decided to create a video that showed off the saw's features, such as the dual laser guide, dual bevel, and 60-degree mitre capability, while also demonstrating how to use these features to make a project.

After giving it some thought, I decided to make a mobile speaker out of reclaimed walnut flooring. This project required the use of the saw's compound mitre feature, which allows for both the angle and the mitre to be set at a degree other than 90 degrees. I felt that this would be a good way to showcase the versatility and precision of the saw, while also creating something useful and unique.

Overall, I am excited to share my experience with Bosch's GCM-18V 216 mitre saw with my audience and hope that my video will be helpful and informative for those considering purchasing this tool.

Selecting your wood:

This project is a great opportunity to use up any small pieces of wood that have been accumulating in your workshop. Instead of letting them gather dust, you can put them to good use by creating a unique and functional mobile speaker.

For my speaker, I decided to use some walnut flooring that had been gifted to me by a friend. He had originally been asked by a client to lighten the wood, but the client ultimately decided to have it ripped up and discarded. My friend knew I was always on the lookout for interesting wood to work with, so he offered the flooring to me. I was happy to take it off his hands and give it a new life as a mobile speaker.

I selected a piece of the walnut flooring that was long enough to be cut into six sides that would follow the grain of the wood. This gave the speaker a cohesive and natural look. Once I had all of the pieces cut to rough length, I used my thicknesser to flatten them and bring them to a uniform thickness. This step is important because it ensures that the pieces will fit together properly when it's time to glue everything together.

If you want to add a touch of variety to your speaker, you can also choose to use multiple wood species. This can add depth and interest to the finished product. Just be sure to make all of the pieces the same size and thickness before moving on to the next step. By following these steps, you can create a beautiful and unique mobile speaker that will impress your friends and family.

Cutting your angles:

The most important step in cutting your speaker sides is ensuring that you have perfectly set angles on the saw. To do this, you can either use the saw's guides (if you trust their accuracy) or, as I did, use a digital angle gauge. If you don't already have one of these in your workshop, I highly recommend getting one. They are useful for a variety of tools, including my table saw, bandsaw, and now this new mitre saw.

Since we are making a hexagon, each angle needs to be 60 degrees. Therefore, we will need to set the saw's angle to 30 degrees. To create a cone shape where the mouth of the speaker widens, we also need to set the mitre of the saw. After prototyping with plywood, I settled on a subtle 4 or 5 degrees. You may want to play around with this number depending on the overall look you want to achieve.

Once these two angles are set for the compound mitre, we are ready to start cutting. However, there is a safety risk to consider. The saw's fence does not extend all the way across and has a large gap in the middle where the saw blade cuts through. This is normal on most saws, and many users will create something to fill this void, especially when cutting small items that may fall into the gap.

As a quick fix, I attached an offcut to span the fence. I used a combination of masking tape and CA glue to attach it in place. This allows me to easily remove it if I need to replace it, without leaving any residue on the saw.

With the temporary fence in place, I added another piece of wood perpendicular to the fence to act as my stop. This helps me to quickly and accurately reference all of my side pieces, ensuring that they are all the same size. Neglecting this step can make a big difference in the final piece and may cause issues when trying to glue everything together.

To cut the sides, place your walnut piece down and cut the first side of your piece. This will give you a side to reference to your stop. Before cutting the next side against the stop, make sure to flip your workpiece over. Be sure to keep your fingers out of the way and consider using a hold down stick to help with this process.

Creating the back:

With the sides cut, it's good practice to check that all of the joints are tight against one another. The best way to do this is to use rubber bands to dry fit the pieces into place. The bands will pull the joints tightly together, and if you have set your angles correctly, the pieces should fit together without requiring any manual adjustments.

I am extremely happy with how this saw has handled all of my compound mitre cuts, and I believe this is largely due to its extremely sturdy sliding mechanism. I have used cheaper models in the past, such as the Evolution Power Tools model, and found that the linear rails and bearings have a lot of "slop" when fully extended. This Bosch model, on the other hand, is extremely rigid and accurately sets all mitre angles.

With all of the sides fitting together nicely, we need to create a back for the speaker. This serves two purposes: 1) it gives the speaker a finished look, and 2) it channels the sound forward out of the funnelled end.

There are a few different ways you can create the back of the speaker, and which method you choose will depend on your level of experience.

Option 1 involves cutting a hexagon to fit into the space and gluing it in place. This is probably the easiest method, but due to the cone shape of the speaker, it can lead to adhesion issues.

Option 2 involves cutting an oversized hexagon, rebating the sides, and cutting a dado into the side sections that this piece will seat into. This method is similar to the construction of a wooden bucket and will provide a solid fix with the best adhesion when applying glue. Although it requires more work, I have chosen this option because I think it will be an enjoyable project that pushes people to try new techniques.

To make the dados, start by taking the sides out of the elastic bands and placing one on the bed of the saw. Set the angle of the saw to 90 degrees, but keep the mitre at your set angle. This will enable you to make parallel cuts. Once you are happy with the location of the dados (slightly in from the narrow end), set up a stop block so you can transfer this measurement to all of the side pieces.

Since we don't want to cut all the way through the sides, we need to use the depth stop function of the saw. Your saw may have a screw that allows you to adjust the depth of cut, or it may have a quick lever like the Bosch saw, which can be moved into place for making stopped cuts and moved out of the way for full depth cuts.

The depth of the cut doesn't need to be too deep, but it should be enough so that the back piece sits well in place. The exact depth will depend on the thickness of your side pieces.

With all of the dados cut, use the depth of the dado plus the size of the opening to cut a hexagon on the saw. If your saw doesn't go all the way to 60 degrees, like mine, then you may want to hand cut this piece out instead.

To create a rebate that will sit within the dado, I found it easiest to use my table saw. I set the depth of cut of the blade that will enable to back to sit flush to the sides and then set the fence to run all sides through. Alternatively, you could use a hand saw and/or chisel to do this.

Glue up:

Before applying any glue, it's important to dry fit all of the pieces together one last time to make sure everything still fits as it should. In my case, I found that the rebates on the back piece weren't as deep as they should have been, which was causing the side pieces to be pushed out slightly. I was able to fix this quickly at the table saw, but it could also have been remedied using a chisel.

Once all of the pieces fit as they should, take them all apart and sand the inside faces. It will be nearly impossible to do this once the speaker is fully assembled, so it's best to do it now to save any frustration later on. I will be using Rubio Monocoat 2C oil to finish this speaker, and Rubio doesn't require a high grit finish while sanding, so I don't go above 150 grit at this stage.

To assemble the speaker, apply glue to all of the faces and then use rubber bands to clamp everything together. You may need to adjust some of the sides to make sure you are getting nice, crisp edges at this point. Make sure to clean up any squeeze out, as it will be easier to do it now rather than after the glue has had time to fully cure.

Finishing touches:

Once the glue has fully cured and all of the rubber bands have been removed, it's time to check that everything is in the correct place and that all of the edges are sharp and clean. If you find that some of the sides have moved slightly during the gluing process, you can use the side of a screwdriver (or any other cylindrical metal object) to push the fibres together and create a seamless look.

Before moving on, it's important to sand the speaker again, but be careful not to go above 150 grit.

Next, you'll need to cut an area to fit your mobile device. This may seem intimidating, but it's actually quite straightforward. Take your finished cone speaker back to the saw and set the mitre angle to the same angle you used previously. This will allow you to make parallel cuts across the speaker.

Set the depth stop on the saw to a depth that will be sufficient for holding your device securely, and set the bevel of the saw to around a 5-degree angle. This will allow your device to sit back slightly. Make your first initial cut and then, while holding your device to that first cut, mark where you need to make your next cut. This method will help minimize any errors that may occur from measuring. Once both cuts have been made, use a chisel and/or sanding paper to clean out the middle between the cuts.

Keep testing the fit of your device and make adjustments as needed. If you want to angle your speaker slightly, you can make wooden legs to help project the sound. Alternatively, you can add feet to your speaker by using small brass pins. However, you choose to add feet to your piece, make sure to enjoy the process.

To finish your speaker, I use Rubio Monocoats 2C oil.

Rubio Monocoat is a popular choice for wood finishing because of its unique formula and excellent performance. Unlike traditional oil finishes, which require multiple coats and long drying times, Rubio Monocoat is a one-coat, single-component finish that dries in just a few hours.

To apply the Rubio Monocoat, start by cleaning and sanding the wood surface. Make sure to remove any dust or debris from the surface, as this can affect the finish. Then, apply the Rubio Monocoat using a cloth, brush, or roller. Follow the manufacturer's instructions for application, as the specific process may vary depending on the product.

Once the Rubio Monocoat has been applied, allow it to dry according to the manufacturer's recommendations. This will typically take a few hours, but may vary depending on the humidity and temperature of your workspace. Once the finish is dry, you can check for any imperfections or areas that may need a touch-up. If necessary, apply a second coat of Rubio Monocoat to achieve the desired level of coverage and protection.

In addition to its excellent performance, Rubio Monocoat is also environmentally friendly. Its single-component formula means that there are no harmful VOCs (volatile organic compounds) released into the air, making it a safe choice for indoor use. It is also non-toxic, making it safe for use around pets and children.

Overall, Rubio Monocoat is an excellent choice for finishing your speaker. Its easy application, wide range of colours, and long-lasting protection make it a top choice for both professionals and DIYers. With a little care and attention to detail, you can achieve a beautiful, durable finish that will last for years to come. In addition to its practical benefits, Rubio Monocoat also offers a wide range of colours to choose from. Whether you want a natural finish that enhances the grain of the wood, or a bold and colourful look, Rubio Monocoat has a hue to suit your needs.

In conclusion, the Bosch GCM-18V 216 mitre saw proved to be an invaluable tool in the creation of my reclaimed walnut speaker. Its precise cuts and sturdy sliding mechanism made it easy to achieve the compound mitres necessary for this project, and the dual laser guide and dual bevel feature helped to ensure accuracy and efficiency.

The process of creating the speaker was not without its challenges, but overall, it was an enjoyable and rewarding project. The use of Rubio Monocoat as a finish added a beautiful and protective layer to the final product, and its environmentally friendly nature was an added bonus.

I hope that this project has inspired you to try your hand at creating something similar, or to explore the capabilities of your own mitre saw. Remember to always prioritize safety when working with tools, and don't be afraid to experiment and try new techniques. With a little patience and practice, you too can create something unique and beautiful for your workshop or home.

48 views0 comments

Recent Posts

See All


bottom of page