One Ring to Unite Them All: Wood Dust Cyclone Construction from Sawmill Creek

This discussion thread started with a woodworker who was trying to figure out how to cut rings of plywood. He was going to assemble them into a dust collector cone, but it seems quite likely that other woodworkers could think of ways to use this technique for other projects, too. What would you use it for? - Editor

"I am trying to decide how to cut the rings of plywood that will assemble into the cone of a wooden dust cyclone. A 15 degree angle vivisection was chosen because of the availability of 15 degree dovetail router bits. 62 half inch plywood rings ranging from 6" interior diameter at the bottom and 22" interior diameter at the top...these rings are measured in 64th's of an inch to get them to line up and form the 30 inch long cone which will be an inch thick. Ring 62, the smallest, will have a topside outside edge that has a radius of 3 41/64" and an inside bottom edge radius of 3". The radius of 3" gives me the 6" diameter, and that is where the dust settles. My dust is unsettled on how to cut all of this.

"It seems pretty straightforward to cut circles to the larger of the diameters of the top of the ring and then route the excess to the lower edge of the outer ring. I could also use a band saw with the table slanted and a circle jig. Actually, that is what I am leaning toward for the outside ring cut. I would just use a circle jig and tilt the band saw table 15 degrees and get the 62 disks without too much fuss.

"But I am having trouble wrapping my head around the inside cut. So, if I use the angled table of the band saw and cut my 62 disks I will have a solid cone. So far so good. One workflow would be to use a jig saw to cut a first pass angled inner circle. And then use a router to finish it. Holding the piece down would be a little dynamic unless I pinned it down with finishing brads because unless I use the outside edge as a guide I don't see a way to keep the circle true for the inside cut." - Bruce

This discussion thread actually mostly turned into a conversation between the original poster and another woodworker, each bouncing ideas off each other for achieving the desired result. Here is the first response to the challenge. - Editor

"A dovetail bit is wider at the tip than at the shank. I believe I've seen bits that are the reverse. That is, they're tapered, with the tip narrower than the other end. If you could find one of those with the angle you want, you could use it in a plunge router-based circle jig to cut the inside face." - Jamie

"I have considered taking the plunge, but how does the inside cut happen without the whole piece moving around? The outside makes sense. Thereis a middle pin, and the router moves around this axis. But with the inside ring cut, where is the reference?...Unless I flip the ring over and use the outside edge as my guide." - Bruce

"I've made wheels with a router and a circle-cutting jig. The router pivots around a pin in a hole in the middle of what will become waste. It works just fine for about 355 degrees of rotation. Then it gets a little dodgy, but it actually does okay. I've been cutting the wheels with a straight bit, doing several passes around the circle to cut down through the stock. Generally there's a little ear left after you cut through. You can clean it up with a knife or a chisel." - Jamie

"I have a couple circle-cutting jigs that I have used to cut holes for speakers or make round blanks ,so I could not get over the conceptual hurdle of twin cuts on the same blank. Cutting all of the outer ring and then cutting all but a tab of the inner ring makes sense. If it gets flimsy cutting 355 degrees, I had the thought that one could cut 175 degrees on the top of the circle and then 175 degrees on the bottom of the circle and have two tabs that need to be cut by hand later. This would stabilize the center waste and maybe it would not wiggle. I will probably use a sharp thin spiral cutting bit to get the dimensions and then come back with the dovetail for the angle. " - Bruce

"If you were closer, I could cut this on my CNC fast." - Steve

"I like the CNC router idea. Combine that with Bruce's idea of nesting the rings, and my tapered router bit, and you could pop those rings out very quickly. I think that programming the machine with those simple objects (circles) would be very simple." - Jamie

Ash Trees from WoodWeb

David Cappaert, Michigan State University, Bugwood.org

"I have two questions regarding ash trees. First, I have two ash trees that I have cut down. Both have a dark brown stain in the center, and this area smells like alcohol - ethyl alcohol, not methyl. To be more specific, it smells almost exactly like hard apple cider. What causes this? I assume it is some fungus. The one tree shows signs of having been struck by lightning several years ago. The second question regards the approach of the Emerald Ash Borer. I live in central Indiana, and there is little question that this bug will reach this area within a few years. What is the best thing that I can do? Would it be a good idea to start clearing ash trees while they are healthy and undamaged and replace them with other trees?" - DLB

"It's really hard to say what caused the smell; each tree species will have a different odor to it when cut. When you mention clearing ash trees, are you speaking of trees in a forested setting, or in a yard? Personally, if the trees are healthy, and the EAB has not been found in your area, I think it is best to leave them be. It's possible that some control method may be developed before the beetle reaches your area. I would, however, walk through your stand regularly to watch for signs of the beetle, and listen to what your state forestry department is saying about the spread of the beetle. You may need to salvage cut your ash, but I would wait it out a little longer." - Tommy

The original poster added a few more details to his situation. - Editor

"The EAB is already in a neighboring county, although that is a recent development. It is not directly in our area yet, but I doubt it will be much time before it is. What I am wondering is if selective clearing might be a way of isolating stands from the bug and so saving them for a while at least. I like ash, and am not particularly interested in seeing it wiped out. I didn't go into very much detail in my first post, sorry that it was unclear. I read somewhere that, on its own, the beetle will only move up to 1/2 mile per year. So an isolated and controlled environment is what I had in mind as a temporary measure. Feasible? Wishful thinking?" - DLB

"As far as your woodlot is concerned, keeping everything healthy there is important, too. Not just for ash trees but everything else as well. The best way to do that is through timber stand improvement. Your local forester can help you with that. Through TSI you clean out undesirable trees. Like damaged trees. It also regulates the stocking of the stand. An acre of land can produce a given amount of wood per year. Making sure that growth goes on healthy trees is important. No sense putting wood on trees that are not worthy. As far as the odor, I don't know what to tell you. Up here black ash have a smell like that when cut. They also have a darker wood. Could you have some black ash there?" - Quinn