Thread: Made a Overhead Dust extractor boom for the Hammer K3

Nice job!! Terrazzo floor as well?

Most likely epoxy floor. Looks good.. so to the o/head extraction.

Nice arm, but I worry about how much fine dust will get through such a restricted hood intake.

Yeah it is an epoxy floor, its seen better days, but is holding up well, apart from where the cracks in the slab and a few chips.

I knew BobL would chime in, he is never happy and would find flaws in a NASA built spaceship

But he is right, it would be better with a bigger hood intake, but i'm keeping with the factory hood for now, unless anyone wants to 3D print a custom hood for the K3 with an 80mm intake.

But at the end of the day, any dust extraction is better than none.

The overhead for a K3 is a problem and more of a problem when you haven't got a a low ceiling to hang the extraction pipe from and the mechanical restrictions of the saw limit the width of the hood unless all the added width is all to one side. Mine works tolerably well though and I haven't worried about making a new one apart from the wish to get it off the riving knife.

Originally Posted by Chris Parks

The overhead for a K3 is a problem and more of a problem when you haven't got a a low ceiling to hang the extraction pipe from and the mechanical restrictions of the saw limit the width of the hood unless all the added width is all to one side. Mine works tolerably well though and I haven't worried about making a new one apart from the wish to get it off the riving knife.

That is why i went with a floor mounted option, my ceiling is 6 mtrs high and i didn't want to span a swing arm 2.7mtr from the wall.

It would be possible to for someone to print an improved verison of the saw guard/hood, with a increased suction area and larger inlet.

I might have a crack at making a new hood in clear perspex and plastic welding it together with a larger inlet, but for now i have too many other projects on the go

I've spend many hours measuring air flows and dust levels around various saw hoods and come up with 3 factors to consider in maximising air flow and hence fine dust removal.

1) The back of the guard should be as open as possible ie completely open. This is one reason why Gilders sounds like works so well. Most guards are semi sealed down boxes - if little or no air can get in resulting in not much fine dust getting out.

2) The best location for max dust extraction that leaves some visibility is directly above where the blade enters the saw plate. Other locations fight the air currents generated by the blade which are substantial. Unfortunately this does still somewhat restrict the view so some comprises may need to be made.

3) When the above are implemented a 4" hose is usually enough. I have to turn of my DC when docking small pieces as they endup being sucked away.

And, as CP says, to make narrow cuts and still cover the blade the hood has to have most of its structure on one side or have some sort of lateral adjustment.

It's taken me 4 goes to get these all into a workable system. I'm lucky that I have the underside of a roof truss 2.4m above the floor immediately above my saw and am able to suspend it from there. It's also able to pivot the guard from side to side to generate enough lateral adjustment.

The WIP for mine is here.
Ducting update.

Why not continue the horizontal beam back towards the wall and run your main hose over that way instead of across the floor??? Nothing I hate more than dust-hose across the deck

Originally Posted by TTIT

Why not continue the horizontal beam back towards the wall and run your main hose over that way instead of across the floor??? Nothing I hate more than dust-hose across the deck

Because it's a 30 second job to disconnect and roll up the the 80mm overhead line and 120mm lower machine hose with the fender quick connects.

When using the K3, i never need to go around the back or that side of the machine when in operation.

If i didn't need to move the K3, A3-31 and N4400, id have an overhead extraction system.

Good info Bob,

It does surprise me how poor the dust extraction is in within this industry, when doing my cabinetmaking apprenticeship in the 90's, PPE and Air quality control wasn't taken seriously, its a little bit better, it depends on who you work for.

It wasn't until i worked on a few Union site jobs that required a full sealed cutting area for MDF that i appreciated decent dust control, it was part of the reason i switched over to Festo/Festool as i could comply better on site with the integrated dust vacuums.

The K3 main dust extraction port on this machine is 120mm, yet the internal hose is 100mm and a poorly designed collector around the blade.

One big thing i've noticed that has made an improvement in my workshop is the Poly drum filter with poly sleeve (M class dust rating (Cat 3) on my Felder AF16

Fine dust is one of those things that is hard to control, but would be a lot better if machines were designed better.

For a while i had a guy in the next shed that didn't use a dust extractor, he always seemed to have a 1 inch layer of wood shavings and dust all over the floor from the cabinetsaw and jointer/thicknessor, i don't know how he put up with it.

It freaked me out one day, when i saw him welding in the shed with that crap all over the floor.

Originally Posted by bryn23

It freaked me out one day, when i saw him welding in the shed with that crap all over the floor.

Yeah the problem with dust is that it usually takes years to have an affect and like smoking it might be not be direct. It's now known that any dust contributes to cardio vascular problems and makes most other diseases worse.

Originally Posted by bryn23

Because it's a 30 second job to disconnect and roll up the the 80mm overhead line and 120mm lower machine hose with the fender quick connects.

It takes a special kind of discipline to avoid even a 3 second job - "Argh - I won't bother setting up/turning on the DC. . . . . this time". That's why I don't recommend mobile machines. In my various visiting to a bunch of DIY and mens sheds its the mobile machined sheds that are usually the dustiest. Auto blast gates are the go but they are expensive for a DIY on a budget. The other thing about mobile machines is the (excess) use of flexy which is a sure fire way to restrict flow. OK - sometimes there is not many other options. I can understand that

I must have a different though process bob than others, if my dusty isn't connected and going, i don't use the machine period, you only use them together.

Having said that, I've lost close friends from Mesothelioma and also my old man to lung cancer, so maybe i look at minimising dust a little more seriously.