A dust-free circular saw!

Every committed woodworker knows this drama: To make fast, smooth, nice, straight cuts in wood, you need a circular saw, so you bought one, but every time you use it, you choke in the awful airborne sawdust, you wade through sawdust, you chew sawdust, you swim and drown in sawdust, and after finishing work, if you actually have the grim determination to finish it, you have to clean the sawdust out of every little place in your workshop. And after spending hours cleaning the workshop, you find that some breeze carried the sawdust into your house, and that your clothes and hair (if you have any!) helped distribute it all the way into your bedroom, bathroom and kitchen. You swear never again to use that darn dirty circular saw, but someday you have a nice idea for a piece of furniture, or simply you need to build a crate, and there you go... sawdust everywhere, once again!

It doesn't absolutely need to be that way.

With some ingenuity, you can modify a circular saw to work so clean that it seems to defy all logic! Circular saws ARE dirty tools, right? How can they ever become clean?

Well, I was so desperate with this problem, that I found a solution. Here it is, warmly recommended for copying.

First of all, I stored away my existing DeWalt DW352 saw, because it didn't have any dust extraction port, nor did it have a structure that would lend itself to convenient modification. Instead, I bought a new saw. It's the absolutely cheapest one I could find, and it's also the ONLY one I could find that does have a dust extraction port! It's an Einhell. That's a German brand, but this doesn't mean much because anyway, like any saw I could buy, it's made in China.

I first tried it with my vacuum cleaner and no modifications, but it got rid of only about one third of the sawdust. The other two thirds kept flying around. This saw, like most, has the motor fan blowing right at the saw blade, efficiently distributing the saw dust evenly all around the workshop! Very clever, indeed...

Also this Einhell saw has an extremely flimsy base. The saw wobbles around on the base, in several dimensions, leading to very imprecise cuts. By the way, the DeWalt, which was much more expensive (but also Chinese-made), was stiff and steady when new, but became wobbly after just a few hours of use. It's supported by means of a plastic bushing, which quickly wore out.

The first thing I did was throwing away the Einhell saw's original base, and making a new base for it. It's nothing fancy, and it cannot be adjusted in depth or angle during use. I build it to cut at 90 degrees, in 20mm thick wood, which is what I will have to do for the next two years. If I ever need to cut different depths and different angles, I will have to put up with the dust of the DeWalt, or take the job outdoors.

The base is simply a piece of 20mm plywood, with three wooden blocks screwed to it that hold the saw at an exact right angle. There is a slit through which the blade protrudes.

The movable protection for the underside of the blade was also removed and discarded. Those protections do offer added safety, but are extremely inconvenient in practical use, and prevent proper dust extraction. So it had to go.

Then I installed a piece of 1mm aluminium sheet, cut and bent to complete the existing hood of this saw, toward the motor side and around the saw blade periphery. It's bolted to the hood, and screwed to the wooden base. I used silicone caulk to seal this piece all around to the existing hood, the motor unit and the base, leaving only a small opening around the gearbox. Through this small opening the fan can blow a small amount of air into the hood. This is one of three openings through which air enters the case, when everything is complete, and that air can cool the gearbox.

Here you can see one of the wooden blocks holding the original hood, and the one that acts as a pedestal to support the motor. Through the use of shims, the height of this pedestal is adjusted to get the saw blade perfectly perpendicular to the base.

A steel strap goes over the motor, holding it down against the pedestal. This makes the saw maintain a very accurate 90 degree angle, much better than any of these saws can ever do with the factory base, which doesn't support the motor!

The saw blade can be installed and removed easily, without removing the base. I made the slit in the base just wide enough to allow this.

Note that I also sealed the dust port to the hood, using silicone caulk. I mounted the machine at such a height on the base that the blade protrudes 30mm from the seating surface.

Then I installed the side cover. It is crafted from the same 1mm aluminium sheet as the other piece. It is screwed onto the wooden base, and then I sealed it to the hood using simple masking tape (not yet done in this photo). That makes it easily removable.

The side cover has a hole at the center of the saw blade. This is the second air entry into the hood. So there are air entries at the center of the blade, on both sides, and the air moves radially out due to the rotation of the blade and centrifugal force, carrying the sawdust along. The third air entry is through the slit in the base, and while cutting, the air is drawn up between the workpiece and the blade, and through the cut behind the blade. This cleans the cut surface very nicely.

Then I cut a piece of 9mm MDF board to a width of exactly 172mm, with very smooth and straight and parallel sides. I used MDF because it's very smooth and so it will glide well while using the saw. I installed four bolts in it, with recessed heads. The bolts go through oversize holes in the main base plate, allowing me to make slight corrections to the position of this MDF plate.

The blade cuts exactly 2mm wide, and I aligned the MDF board so that its right edge is exactly 40mm from the right edge of the cut line, and the left side is exactly 130mm from the left side of the cut line. This allows me to to cut along a ruler or rail, clamped to the workpiece at easy to remember, round offsets from the intended cut line, on either side of the saw, and get precise dimensions. This is a big plus to allow fast and precise woodworking.

Of course, if you prefer you can use different dimensions, but I do recommend that you choose them so that the edges of the board are a nice exact round number of units away from the blade! And of course, blade and board edges must be exactly parallel. Otherwised the cuts will become wedge-shaped!

Here you can see the whole thing from above. Note the large washers on the bolts. They cover the oversize holes, allowing adjustment of the MDF board by about 1mm in every direction.

Since the MDF board is 9mm thick, the blade now protrudes 21mm, which is ideal to cut the 20mm plywood I need to work with for the next  two years at least.

And here is the complete modified saw, with the vacuum cleaner hose attached.

The vacuum cleaner is the type that uses a water filter instead of any dry filters. This combines excellent filtration quality with a pretty large dust collection ability, and zero cost for filters.

 It works like a charm! I can work for hours with closed windows and doors, if I want, and there is no trace of any airborne sawdust. All fine particles are absorbed, and almost all coarse ones too. Only a very few coarse sawdust particles fall down through the cut, but I would estimate these at far less than 1% of the total, and since these are ONLY coarse particles, they don't fly, don't move, basically staying put where they fall, until I vacuum them up.

Despite the elimination of the bottom saw blade cover, this modified saw is pretty safe. While sawing through a board, there is no way to put one's fingers in danger. This is actually much safer than with the unmodified saw! Only when lifting the saw off the workpiece, one needs to be careful that the blade has stopped. And when setting down the saw, it has to rest on its side, not with the blade down, because that would dent and scratch the surface you place it on!

 This saw modification has changed my life! Now I can do woodworking, without the mess that used to be associated to it!

Since this saw is now half Einhell and half my own creation, I suppose I have to call it the Einfred saw! Manhell, which would be the other option, doesn't sound so good really...!

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