Thursday I got some quick time to work a bit more on the cyclone, and I got a bit further on the project. I’m hoping I can be done on Friday. The only thing left is to cut the holes for the PVC and assemble it. I set up my router with the smallest straight bit I had, and used the Craftsman edge/circle guide I had bought ages ago on clearance and never got the chance to use. The widest, uppermost part of the can measured a 20.25″ diameter opening. So I set the guide up with a 10.125″ radius and attached the pivot to a sheet of MDF about where the middle was – or enough to avoid all the existing holes I had from the UTS project. I used the router and circle guide and routed a shallow ‘moat’ at that 10.125″ distance. Once I was happy with the depth, I adjusted the radius a bit wider (by feel, no measurements) and made a wider concentric ‘moat’ (moat meaning partial-thickness cut) about a half-inch out. I was satisfied with that distance, so I moved the radius back in slightly to take care of the section between the two cuts. That done, I adjusted the radius back out to the outer line and kept increasing the depth of cut until the circle came free of the rest of the sheet.
What this process did was make my circle, and a perfect rabbet along the circumference where it would sit on top of the can. I then tested it by resting it on top of the can. Well, my cut was so perfect I had a little trouble getting it back off the can. I might have to sand that down just a little bit, but I couldn’t ask for much better. Happy with the top piece, I marked prospective locations for the two PVC pieces to insert through. One is right in the middle, the other is right at the edge. I might have to move that one in just slightly.
Moving on to the second piece of MDF, I set it up similarly except I made the circle smaller so it could fit inside the can. I also didn’t need a rabbet on this one, so it was just a matter of dialing in the diameter. Once I had the right diameter for about where it needed to be, I marked a straight line out from the pivot point to the edge. This was my reference to make the 120º line. Between these two points on the short arc, the diameter did not change. On the long arc I measured in 1.125″ for the radius and I made a couple of cuts until it was full thickness. What this did was make that pie piece longer to catch the debris and take it along the can where centrifugal force will take it along the edge to where the arc is smaller, where it will then drop down into the can. That’s the theory, anyway.
I will say one thing – I hate working with MDF. I might cut it on the table saw, but that’s the last thing I will do with it inside my shop. Any other unfortunate incident where I’m forced to work with it I will work outside in full gear. It gets everywhere, and knowing me I didn’t think to put on my respirator. Yeah, dumb. It’s the last time. Part of the reason I’m making it out of this is to use up what I have and whatever is left gets tossed.
I forgot to take pictures of the progress, mostly because I had dust everywhere. Tomorrow I will clean up and take pictures, and those will head the next post. These are from yesterday.