As part of the Christmas gift-making post-mortem, it's time for upgrades to our dust collection system. One of the first was to get a cyclone type separator. I'm notoriously cheap (usually to my detriment), so why buy when I can make one! The most interesting and seemingly workable was the Thien Cyclone Separator. Looking over the pics and reading and re-reading the plans, I decided it was within my capabilities.
However, since there is not a pictorial how-to on making one of those, I decided to fill the gap and maybe accidentally be of use to someone. I am the ultimate "If he can do it, then so can I!" example, so if you feel like making a cyclone for yourself, have at it!
I'm not going to get into the nitty gritty details as far as trash can diameter and stuff like that...I think the Thien plans do a good job there. So mainly I'm just going to describe how I implemented the plan.
Start off with the top of the lid. I was about to use MDF, but then I found a spare piece of pretty ugly plywood laying in the shop which was large enough, so I used that.
I used a drawing compass to get the shape and rough cut it with a jigsaw, making sure I was cutting outside the line (so the circle was too big). I then drilled a small hole in the center where the drawing compass had been and drove a nail through it so that the pointy end was sticking through maybe 1/2".
The reason for that was so that I could do the rest of the shaping with the router. I don't have a circle jig of any kind, so I had to improvise. Fortunately I have a small router table (sitting on my worktable), and I thought there must be some way to fix a rotate point for the center of the circle so that the edge of the circle hits the router bit. I needed a distance of something like 9" away from the router bit, and strongly supported. I realized I could make something to rest on the work table and then just clamp it to the router table so that everything was well supported and not moving. Some spare 2 X 4's did the trick. I drilled out a hole in the end for the nail to fit into snuggly.
This worked out incredibly well because the idea was to sneak up on the edge I was looking for, not only to make the outer edge of the lid (and baffle) but also for the rabbet on the lid. These adjustments were easily accomplished by sliding the 2X4 along the front edge of the router table to get the desired distance from nail hole to router bit edge.
This is me setting up the baffle for rounding.
Once the lid and baffle are cut and rounded, then I put the rabbet in the lid using the same router circle setup. I started with the router bit barely above the table top and only taking off a small amount. Then I'd remove the lid and fit it on the trash can. Once the lid set flat and snug, I knew I had reached the desired rabbet width. So I'd leave the circle jig at that distance and just make successive cuts with the router, slowly raising the bit, until I had a rabbet about 3/8" deep. That gave me a very snug fitting lid.
Here is the lid with rabbet and the baffle (with the nail still in it) stacked on each other.
(to be continued)
However, since there is not a pictorial how-to on making one of those, I decided to fill the gap and maybe accidentally be of use to someone. I am the ultimate "If he can do it, then so can I!" example, so if you feel like making a cyclone for yourself, have at it!
I'm not going to get into the nitty gritty details as far as trash can diameter and stuff like that...I think the Thien plans do a good job there. So mainly I'm just going to describe how I implemented the plan.
Start off with the top of the lid. I was about to use MDF, but then I found a spare piece of pretty ugly plywood laying in the shop which was large enough, so I used that.

I used a drawing compass to get the shape and rough cut it with a jigsaw, making sure I was cutting outside the line (so the circle was too big). I then drilled a small hole in the center where the drawing compass had been and drove a nail through it so that the pointy end was sticking through maybe 1/2".
The reason for that was so that I could do the rest of the shaping with the router. I don't have a circle jig of any kind, so I had to improvise. Fortunately I have a small router table (sitting on my worktable), and I thought there must be some way to fix a rotate point for the center of the circle so that the edge of the circle hits the router bit. I needed a distance of something like 9" away from the router bit, and strongly supported. I realized I could make something to rest on the work table and then just clamp it to the router table so that everything was well supported and not moving. Some spare 2 X 4's did the trick. I drilled out a hole in the end for the nail to fit into snuggly.

This worked out incredibly well because the idea was to sneak up on the edge I was looking for, not only to make the outer edge of the lid (and baffle) but also for the rabbet on the lid. These adjustments were easily accomplished by sliding the 2X4 along the front edge of the router table to get the desired distance from nail hole to router bit edge.
This is me setting up the baffle for rounding.

Once the lid and baffle are cut and rounded, then I put the rabbet in the lid using the same router circle setup. I started with the router bit barely above the table top and only taking off a small amount. Then I'd remove the lid and fit it on the trash can. Once the lid set flat and snug, I knew I had reached the desired rabbet width. So I'd leave the circle jig at that distance and just make successive cuts with the router, slowly raising the bit, until I had a rabbet about 3/8" deep. That gave me a very snug fitting lid.
Here is the lid with rabbet and the baffle (with the nail still in it) stacked on each other.

(to be continued)