Perfect DIY!!!!! As uttered by Tito Boy in Bandila (A News Talk in the Philippines), IKAW NA!!!!FLUSH MOUNTING DRIVERS IN MDF
Now, I am not an expert at this, far from it, information presented here
Is gathered from the web and from what experience I have found along the way, and if anyone has a better idea or an easier way, please include it here because this is to help anyone in the same shape as I, looking for information to help them along their journey through this wonderful hobby of DIY audio!
I suppose we will start with a tools list, this is what I used but once again, if anybody has suggestions…..
1. PLUNGE ROUTER. Probably the most important tool for this job, they come in many sizes and prices, my suggestion would be to find one with the smallest diameter body so you can cut some of the smaller mounting hole, with a bigger bodied router you are limited you may not be able to route out a hole for that 4" mid.
2. CIRCLE JIG. Runner up in the important tool list, you just cannot make perfect circles without some kind of jig, there are many commercial units available, Jasper being one of the best known, but making
your own is very simple and quite inexpensive; I will address this in my next tutorial.
3. ROUTER BITS. You will need two different bits for this project, first, a ¼” straight cut up spiral bit, which performs the main cuts and also helps to removes the MDF dust from the groove as it goes, (a regular straight bit will work also)
Second, a ¾” flat bottom bit to cut the recess groove for your drivers, these should be carbide tipped of course, my last non-carbide bit I tried was the ¼” straight cut bit, it lasted for two projects before it was to dull to use.
4. FLAP WHEELS. These little jewels are priceless when finishing the inside edges of your mounting holes.
5. DRILL. For pilot holes mounting holes, and Flap wheels.
6. PIVOT PIN. This is your pivot point for the circle jig, this can be a nail with the head cut off, or even a drill bit, I used a drill bit on my last baffles as the hole you drill for them is exact, so it works well.
ROUTING SOME WOOD!
The first step here is to determine your outside diameter of your driver for the recessed groove, and the through hole diameter, hopefully you can find this information from your retailer or manufacturer, if not, you can use two framing squares to find the diameter by turning your speaker face down, (protect your surround on the speaker) and laying the squares on the outside edges of the driver forming a square, measure the inside edges of the squares to find the diameter. Do the same for the through mounting hole.
Once you have determined your diameters, you must layout your driver placement on the baffles, then mark your centers for each driver, this is where the pivot pin is placed, the picture below shows the drill bit I used and the ¾” flat bottom router bit
Now measure the mounting flange thickness of your driver to determine the depth of your recess, if you want the driver surround recessed include this in your measurement, just don’t go so deep as to weaken the baffle you will be attaching to, for mids, I would keep it at least 3/8” thick.
Take your ¼” straight bit and make a shallow cut the diameter of your recess, then switch to the ¾” flat bottom bit and remove material in several passes down to your pre determined depth as shown in the above illustration.
Now, switch back to the ¼” straight bit, and in several passes, cut out the mounting through hole, many say to leave a small amount of material at the bottom of the groove and cut it with a razor knife afterwards, on small drivers I cut straight through myself as the circle jig will support the router when the plug falls free, use your own judgement on this one. Afterwards, use the flap wheel to finish out the inside of your hole, hopefully you will end up with something similer to this:
I hope you find this helpful! Happy building!!
I'm sorry I could not get the pics in the right place, I need to find a way to upload the word file or host it somewhere.