With things back to normal..
Next comes knocking off the square edge on the laminate left by the flush trim bit. If the edge is left square it's not only sharp(easily solved with a laminate or mill file), but the square edge is pretty prone to chipping if it's knocked against something. So, typically, laminate is chamfered with a router bit. I didn't like the look of a chamfer so I used a
very slight cut of an 1/8 inch round over bit.
With the laminate edges finished, I now can get at the hand plane chamfer around the coax area.
..and with that done..a trial run
At this point I finished two additional radius roundovers to the inside edges of the sides. I didn't take any pics of this as it's hard to see. I did a 1/8th inch roundover for four inches below the coax chamfer(where the sides dip in before coming back out in the lower section of the speaker), just enough to break the edge to look nicer, and a 5/16ths roundover the rest of the way around the inside edge of the sides. Then came sealing the edges, sanding sealed edges, more sealing, more sanding.....long process and not terribly interesting. It's a tedious process.
Next up was doing the finish sanding (150, 220, 320 grit) on everything that was getting painted. This includes all the edges of the sides, the inside face of the sides, and the entire internal assembly that would be seen after the sides are installed. I'm using Target Coatings lacquer primer, color coat(black satin), and topcoat. Their tech sheets indicate everything should be sanded to 320..soo..lots of sanding.
The sides and internal assemblies are ready for primer.
BUT..before breaking out that equipment, I figured I better finish the grill frames so they can be painted at the same time. And as long as I was making grill frames, I decided to make a new set of (magnet attached rather than velcro type) grills (4 total, 2 front, 2 back) for the LFTs as well as new side & top trim pieces for the LFTs. I'll be using cherry wood for the new trim pieces. Making all six frames at one time is much easier as they are made of all the same materials, same dimensions, same machine setups, same paint.
I started with the tops of the SVs.
I laid out the tops of the grill assembly and rough cut them out. This is trimming the tops flush with the same template I used wen finishing the radius on the coax baffles.
and a test fit.
The frames will be assembled with half-lap joints and lots of glue. I decided to use MDF for the most of the frame construction. I milled own QS oak previously, but even though the wood was quarter-sawn, they still had a slight warp to them. Rather than fight that, I just remade all the pieces I needed out of straight-flat MDF. Dimensions are 5/8ths x 3/4. The 3/4 face will lay against the baffles. There's a heavy roundover on the outside edges that pares the 5/8ths down closer to 1/2 inch. I soaked all the MDF frame pieces with CPES (cold penetrating epoxy) to give the MDF a little more strength.(?) I've had this CPES for 25 years..I figured it can't hurt and might as well use it up.
I rounded all the edges of the grill frames on both faces, as needed. The cross supports are the oak that I cut previously at a thinner dimension (1/2"). After rounding the edges on both faces of the cross pieces they were nearly round and quite small. Much smaller than the ones they're replacing (the grill in the pic is the front grill on the LFT speaker). The grill frames for the SVs are the same.
Next comes the slot for mounting the grill fabric. I'll be using the spline/fabric/slot method for mounting the grill fabric. If you've ever replaced screens on your home windows (I've done this on two homes) this is the same process. I used a 1/8th inch slot cutting bit with a larger bearing. The bearing reduced the slot depth from 3/8ths inch to 3/16ths.
This just uses a lycra sample I had. It's the same fabric weight as I'll be using (solid black more opaque spandex).
I used a tall fence jig to support the frames as I cut the slots.
One thing I didn't anticipate when I used half laps to assemble the frames is cutting the slot. The slot pretty much cuts the half lap tongue of the cross piece right through. As much as I try to think/plan four steps ahead, some things are missed now and then. This is the worst oversight yet..which is really pretty minor. I cut the slot as far to the outside as I could to leave sufficient glued surface. It'll be fine. MDF is dusty to work with, but it is easy to shape and when you use LOTS of glue, it glues up similar to welding two metals together.
The frames have been rounded over, sanded and sanded and sanded. They too are ready for paint.
