Firstly, we want to use mdf. Mdf is a type of wood that is made by sticking sheets of recycled wood together. You can purchase it from the hardware shop in various sizes and thicknesses. For this one I have used some 18mm thick mdf that I had lying around. You should use mdf over chipboard (chipboard is made from the same material, but is chips of wood glued together and pressed) as chipboard swells with the smallest amount of moisture and crumbles easily.
Athough not covered in this part of the tutorial yet, it’s an excellent idea to give the spacer a coat of paint to seal them in so that the wood isn’t affected by moisture. I will do this later in the project as time is a factor at the moment.
Anyway, the frist step is to draw some circles on the mdf to prepare for cutting. There are a couple of ways to do this. One way is to make a template which you can test fits in the space and make sure the left and right are the same size. Another way is to measure the diameter (width of the circle) and find something around the same size and trace around it. That’s what I did. Either way, you need to make a circle around the same size as the outer ring of the plastic speaker mount that we removed earlier, and an inner ring the same size as the inner area of the mount. Ideally, when we cut the inner circle, the mount should sit inside it comfortably.
Don’t worry too much about getting it exact, but err on the side of larger rather than smaller. You can always sand it back if you need to. Worse case scenario, you can cut another one.
For cutting the spacer, you’ll need a drill with assorted drill bits, a hole drilling bit and a jig saw. All of these you can pick up pretty cheaply from Bunnings (or any hardware store) if you need to. Most people already have things like that, so either use your own or borrow one.
Once the holes are drawn, you’ll need to get the jigsaw bit in there, so you’ll need to cut a hole in the middle big enough to start the jigsaw. Use the hole drilling bit for this and drill a hole somewhere in the middle. It doesn’t have to be accurate, it’s only to get the jigsaw blade in there.
Now that you have the holes to start, it’s time to make the first jigsaw cut. Remember that you should make the iside cut first as it’s easier to hold the board, rather than if you cut the outside first and have to hold a small circle. You should always use the appropriate safety gear and where possible, use saw horses. I don’t have saw horses, so old milk crates suffice.
You’ll notice from the off cut on the ground, start at the centre hole and work your way in a spiral motion until you hit the first drawn circle. then follow the circle around (don’t cut the jigsaw cord!) and keep going until you complete the circle. It’s best to do both at the same time so you end up with two large holes in your board.
Just take a moment to check the size. The easiest way to do this is to sit the plastic mount inside the cut you’ve just made and check that it fits inside fairly snuggly. If it doesn’t, either make the cut again if it’s way out, or use some sandpaper to smooth it down to make it fit. Another good way to check (and you really should do this) is to see if the speaker fits in there. If it’s too small, the speaker won’t sit flush against the wood. If it’s too large, the holes for the screws to affix the speaker will be too close to the edge.
Next, cut the second inside hole. Once they are both done, it’s time to cut the outside circle. We don’t need to drill a hole for this as you can just start from the edge of the board. Go around in the same motion as the inside circle. Once complete, you should have a spacer looking piece of wood as below.
Then go through and make the second cut. You can check that the sizing is right by sitting the plastic mount on top and gauging the size. Once finished, you should have two spacers that are similar in size to the plastic mount.
Now that we have the spacers, we need to be able to mount them to the door. We do this by drilling holes in it. You can use the original screws that you removed to take the plastic mount out, but they are too short, so we’ll need to countersink them.
Get the first spacer and place the pastic mount inside it. Then use the screw holes as guides and mark where they are. It’s a good idea to write “TOP” at the top of the spacer so you know which way it sits up in the car. Once you’ve marked the where the holes should be, get the appropriate drill bit size (err on the side of smaller here if you aren’t sure) and drill the holes through.
Next, we need to countersink the holes. This means that we drill a hole the same size as the head of the screw (maybe a tiny bit bigger) so that the screw can go further into the wood. I used a small sized hole drilling bit, but if you have a large drill bit it will work just as well. Not only does this mean that you can use the original screws and they won’t get in the way when we mount the speaker on top. After the countersink holes are drilled, it should look like the picture below.
The final step is to attach it to the door with the original screws (put the “TOP” bit at the top) and make sure it fits.
Next, we mount the speaker…