"Look at the past - empire succeeding empire - and from that, extrapolate the future: The same thing. No escape from the rhythm of events. Which is why observing life for forty years is as good as a thousand. Would you really see anything new?" - Marcus Aurelius
The original post explaining the reasons why I'm building Voigt Pipe speaker cabinets is here.
This is the first update on that project. I haven't moved very far along due to other chores that were of higher priority. There were also some issues with tool and material availability, as well as a screw-up :(
In that previous post, I stalled out due to having to make mirror-image diagonal cuts in a couple of rectangular boards. I purchased a fine-tooth circular saw blade and installed it on the old Makita worm-drive saw. The thing is a beast, but it could probably use a little TLC.
I spent *a lot* of time making darn sure the diagonal cuts would be exactly where they needed to be. Red oak plywood is expensive, and I didn't want to buy another sheet. They were funky cuts, so I was a bit uneasy about making them, but I finally bit the bullet and made the cuts. Happily, they came out clean and straight, and with the correct dimensions. The wood didn't even kick when I finished the cut - which usually happens when I make hand cuts.
Below: The first pair of speaker cabinet sides, with the guide still clamped to one side.
The two halves with the cutting guide removed
Below: All the sides cut. Somehow I managed not to screw them up. They are identical.
I made a run to town, only to find that Home Depot was completely out of red oak plywood. I bought some 3/4" birch plywood instead, and now they will look similar to the shop cabinets I built a couple of years ago. With the same wood stain, they should fit right in. I made the correct cuts with the new birch plywood, and now I just need a little time to make some minor cuts and then begin assembly.
In the linked diagram below, you will notice that the back side of the cabinet is at an angle. As a result, the back panel needs a slightly angled cut at the top and bottom so that it can sit square to the top and bottom. A 7 degree slice needs to be cut on the bottom and top edges that so that the rear cabinet joints are flush. I still need to do that.
https://drive.google.com/file/d/1OVjDQaTqrq7KNBUptcnbwGnzjOXB_LF-/view
When I started this project, I didn't have a tool for making a large clean hole, but it recently arrived in the mail. I own a jigsaw, but any circle I tried with that would turn out poorly, for sure! The guy in the video below shows how to make a clean circle.
Today I woke very early prior to night shift. I got some groceries, then brushed out the dog. Who knew Huskies shed every autumn? I didn't! I guess the undercoat is being replaced for winter. When I was done brushing her, the carpet looked like something had killed and eaten a Husky, leaving fur all over the floor. Messy. I had to change clothes, too. She was worse in the spring.
After I got all that done, I could finally look to my own interests - the business of making audiophile grade cabinets - or so I hope...
I made a test cut on a spare piece of plywood - because I'm not as stupid as I look and testing indicates.
I learned a few things about the circle cutter in the process. You can adjust the depth of the center drill and the circle cutter, and you definitely want the center drill to go deeper than the circle cutter. Why? Because you don't want to cut clear through - that will make a ragged hole on the bottom side. Instead, you let the center drill punch through first, then flip the wood over and use that center hole to align and finish up the circle from the bottom. That way the hole edges are clean on both sides! I made sure to set the drill stop so that the circle cutter would not hit the steel table, then break off and kill me. It's a little unnerving to make the cut, with that arm spinning around without a guard.
I learned that a large circle takes a very gentle touch with the drill press, or it will stall out and the drill press drive belt will squeal. A smaller hole can be cut pretty quickly, and with more down-force.
I also learned that the markings on the arm aren't too accurate, so my first test hole ended up being too large to mount the driver properly. The fit was a wee bit sloppy. I could have made it work, but preferred to make an adjustment, and get it right for the actual speaker cabinet.
Satisfied that I had good final adjustments on the circle cutter, I marked the centers for each hole on the front panels. Just to be double-plus sure that I had the right placement and diameter, I used some drafting tools and inscribed a circle on each front panel. I picked these cool drafting tools up at a thrift store for $5. Everyone uses CAD these days instead of actually drafting, so you can find these very nice stainless steel for cheap. It's kinda sad that those skills are being lost.
Below: About to make the first circle in the first front panel. If you look carefully, you can just see the arc of the scribe. I made certain the circle cutter lined up directly on top of them before digging in.
Afterwards I made a smaller test hole for the binder post cups on the scrap of plywood I had already ruined with the big hole. The first cut made a nice tight fit. Then I cut small holes in the rear panels.
The build instructions call for bending a plate of 1/8" aluminum in a gentle radius to direct sound from the vertical cabinet out the horizontal bottom horn opening. It's a difficult bend for a DIY guy to make, requiring the use of metal rolling equipment or a hydraulic press. I'm not going to do what the guy in the video below did. Nope.
Instead of aluminum plate, I'll be using several thin sheets of plywood. I'll score them on the back sides so that they bend easily. Then I will stuff them into curved grooves in the side panels. I'll make the curved grooves using a template and a router. That should work.
So at this point, the major cuts are done, except for the horn openings at the bottom of the front panels. Soon we will be able to begin assembly!
... and I had barely finished this part of the project, when it was time to go to work. I ran out of time, left a mess behind. Typical...
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