Deadeye
Established Member
Now then. Be gentle - I'm just starting with all this woodworking stuff and, for me, half the fun is learning and solving the problems.
Some background: practical things have long been a relaxation from a desk-based life; but until lately I've had no time. I'd always promised myself that when I retired I'd treat myself to some decent tools, decent timber and, well, make stuff. Well, events overtake you - so retirement isn't going to be quite as planned but, nevertheless, I am trying to learn a whole new skill set.
And I've started by building a cyclone. Perhaps not absolutely perfect from a physics point of view, but works fantastically well! It might be that I got lucky and the size/shape/capacity of my design jsut happen to work. However, I'm just slightly inclined to believe that the fully optimised versions (I found the link subsequently) might be a lot more effort for marginal gain... but I'm sure you'll tell me!
What I did:
I got a square piece of 3mm polycarbonate sheet, side 105cm, and cut a 5cm strip off one side (bandsaw) then a quarter circle, radius 100cm (jigsaw). I then cut off an inner quarter circle radius 30cm (jigsaw).
I butted the cone edges together and joined by drilling through the strip and bolting together with dome-headed machine screws (dome on the inside). My first attempt at glueing made the plastic brittle and it split. I also found that a 25cm radius was too tight for the base.
I cut two circles of 12mm ply to match a) the top plus a few cm, and b) to act as a lid for a plastic barrel (plus a few cm). I routed a groove in the upper one to fit the top of the cone and cut a hole in the lower to fit the narrow end. I added some near-right-angle braces to the base (mild steel x 4).
The bottom ply disk sits on a large plastic barrel that has top cut out and draught-strip glued round rim. I've attached 4 pegs inside that hold open a sack below the base of the cone that cathes all the dust/chips. A bin liner was too light, but a heavy gauge refuse sack works well.
I tried to work out the cut to have a horizontal intake at the top of the cone. I did the 3-d solid geometry ok to solve the intersection of the cone and a cylinder, but couldn't "unfold" it to work out what cutout to make on the flat quarter circle. Problem solved by using a 90-degree bend piece through the top disk at the edge.
The centre of top disk is attached to a HVLP chip extractor by flexible 10mm hose; the 90-degree intake piece is attached to a hose that runs to whatever machine.
I sealed all the joins with clear silicone to keep airtight. The draughtstrip seals down nicely onto the drum. The output of extractor runs to catflap (!).
And it works a treat!! I have run with a planer/thicknesser (big chips) and it produces the best fire-starting kindling in the big bag. For fine dust (drum sander and router) it produces a standing spiral down the cone. Just for curiousity I put a collector bag on the output form the extractor to see what was being missed (and spat out into the garden) - it came up clean after using all the bits of equipment I have.
Drawbacks: it's quite big; it looks rather Heath Robinson; it won't pick up anything heavy (HVLP)
Advantages: it cost c. £30 (mainly the polycarbonate); it works and, as a first "garage thing", I feel boss!
Maybe I got lucky, but overall my conclusion is that cyclones are quite forgiving. A bit of variation in angle and pressure is ok and will still work phenomenally well.
Some background: practical things have long been a relaxation from a desk-based life; but until lately I've had no time. I'd always promised myself that when I retired I'd treat myself to some decent tools, decent timber and, well, make stuff. Well, events overtake you - so retirement isn't going to be quite as planned but, nevertheless, I am trying to learn a whole new skill set.
And I've started by building a cyclone. Perhaps not absolutely perfect from a physics point of view, but works fantastically well! It might be that I got lucky and the size/shape/capacity of my design jsut happen to work. However, I'm just slightly inclined to believe that the fully optimised versions (I found the link subsequently) might be a lot more effort for marginal gain... but I'm sure you'll tell me!
What I did:
I got a square piece of 3mm polycarbonate sheet, side 105cm, and cut a 5cm strip off one side (bandsaw) then a quarter circle, radius 100cm (jigsaw). I then cut off an inner quarter circle radius 30cm (jigsaw).
I butted the cone edges together and joined by drilling through the strip and bolting together with dome-headed machine screws (dome on the inside). My first attempt at glueing made the plastic brittle and it split. I also found that a 25cm radius was too tight for the base.
I cut two circles of 12mm ply to match a) the top plus a few cm, and b) to act as a lid for a plastic barrel (plus a few cm). I routed a groove in the upper one to fit the top of the cone and cut a hole in the lower to fit the narrow end. I added some near-right-angle braces to the base (mild steel x 4).
The bottom ply disk sits on a large plastic barrel that has top cut out and draught-strip glued round rim. I've attached 4 pegs inside that hold open a sack below the base of the cone that cathes all the dust/chips. A bin liner was too light, but a heavy gauge refuse sack works well.
I tried to work out the cut to have a horizontal intake at the top of the cone. I did the 3-d solid geometry ok to solve the intersection of the cone and a cylinder, but couldn't "unfold" it to work out what cutout to make on the flat quarter circle. Problem solved by using a 90-degree bend piece through the top disk at the edge.
The centre of top disk is attached to a HVLP chip extractor by flexible 10mm hose; the 90-degree intake piece is attached to a hose that runs to whatever machine.
I sealed all the joins with clear silicone to keep airtight. The draughtstrip seals down nicely onto the drum. The output of extractor runs to catflap (!).
And it works a treat!! I have run with a planer/thicknesser (big chips) and it produces the best fire-starting kindling in the big bag. For fine dust (drum sander and router) it produces a standing spiral down the cone. Just for curiousity I put a collector bag on the output form the extractor to see what was being missed (and spat out into the garden) - it came up clean after using all the bits of equipment I have.
Drawbacks: it's quite big; it looks rather Heath Robinson; it won't pick up anything heavy (HVLP)
Advantages: it cost c. £30 (mainly the polycarbonate); it works and, as a first "garage thing", I feel boss!
Maybe I got lucky, but overall my conclusion is that cyclones are quite forgiving. A bit of variation in angle and pressure is ok and will still work phenomenally well.
