This latest project is another Dipole. These are baffles cut for an NaO Note II RS dipole speaker system. These are complex specialty baffles featuring front and rear routing and custom roundovers for both drivers and outside edges. The initial drawing was separated into front and rear view then toolpaths assigned to each side independently. I then had a choice to either chuck up a regular piloted roundover bit, hang it off the Z axis and use it like an upside down router table to cut the various roundovers, or to realign the baffles and use a CNC program to cut them. I chose to program cut. The reason is the end of the edge roundover and “waves”. If you’ve ever used a roundover bit you know how useful a router table can be when you come to a corner. If you run a roundover down an edge but you only want to round over one edge the bit tends to round the corner anyway because the pilot bearing follows the square edge of the piece so it’s unsupported the last inch or so of the cut. Using a router table to hold the bit while you run the piece down a fence prevents that from happening. But a table can often leave waves where the work slides down the fence. Hand pushing a piece across a fence means the cut speed is not consistent so the cut won’t be either. In addition It takes a flat table, a well placed razor straight fence and a steady hand to cut perfect roundovers on a table. A CNC program eliminates all those issues, provided you can align the target edge with the center of the bit.
To realign the newly cut baffles after the front was cut, 7/16x .5″ holes were drilled into the MDF spoil board table top to support 3/8″ hardwood dowels. The dowels were then used to align the baffle after it was cut out and all roundovers for all front facing contours were complete. After the front side was finished I pushed dowels into the holes and realigned each baffle separately using cardboard shims to center and guarantee a tight fit. Once aligned I clamped the piece down with some hardwood screw clamps I made then cut the roundover for the rear side of the two midrange drivers first. Next the tweeter pockets were cut using a 3/8″ end mill. To cut the last and most critical roundover I had to remove the dowels holding the upper part of the baffle. But first I used no less than 5 edge clamps to secure the piece to the table. After double checking the piece was secure I removed the dowels and ran the outside edge roundovers one side at a time. Moving clamps in between. There wasn’t enough room on the edge of my table to place a clamp so I had to clamp inside the large midrange opening, moving the clamp from one side to the other so they were firmly supported while cutting.
The result is a custom, two sided work of art that will soon display itself as part of a newly built NaO II Note RS Dipole.The finished baffles are pictured below. One is a front side, the other is a rear side. Thanks to the owner for his permission in using these images.