Recently, I tried planing a 1’x2’ section of my (former) work surface in order to improve my cuts. Not long after, my wife pointed out that the hardboard dust was finding its way into the furnace, and stinking up the house. I’m not brave enough to argue with a pregnant lady, so I agreed not to plane the bed until I had a dust collection method sorted out.
I had wanted to be non-invasive to the parts I already had, so I thought I’d be clever and design a cover for the hole on the metal sheathe. I’m not sure if it’s got a name, but it’s the wide hole that exposes the collet-lock button.
I’m betting most of you have already figured out why that’s a dumb idea, but in case it’s not clear: when the router is actually down in the shaft to cut material, it blocks that hole almost entirely! I have no idea what I was thinking, but I made 5 revisions of it before realizing.
I did test my latest version on a handful of sawdust, and while I could feel a slight draft near the bit, it didn’t really pull up much dust. I’m hoping that it could pull in the dust as it flies off the bit, but I won’t know until I try :P.
It's a few degrees too narrow still, so there's a slight gap on both edges
The zip-tie holes are way too small for the 0.3mm resolution I printed, and for the zip ties. I just used them as stops so the ties didn't slide off.
This is meant for a garden hose. The idea being you cut off one end of the hose, and it just pressure fits in. Then you can use the rest of the hose to run alongside your power cables, and adapt to a vacuum. This way you have a threaded quick connect without worrying about printer tolerance.
For now I think this isn't too valuable, but maybe there's some potential there.
That’s pretty neat. I’m surprised, but it opens in my phone’s browser window!
DeWalt make an adapter like that. IIRC, it sort of fits the 1 1/8" hose. I didn’t like it got the reason you mentioned, it gets blocked when you lower the bit.
A garden hose is really too small for this application though. The area of the hose is really important. Your vac won’t be able to pull enough air through there.
I’m also convinced that a good dust collection needs to have the bristles to stop the high speed chips. Then the vac can pick them up. The design I’m using does ok, except for the chips that escape.
On a side note, shouldn’t your furnace have a filter that would remove the chips?
On a side side note, congratulations on the pregnant wife! We are expecting our second in January.
Failed dust collect… I know the feeling. I do understand what you where going and the water hose is a cool idea, but it might face the same issue as my failed dust shoe…
I’ve designed a dust collector, of which the upper part is around the Router’s collect. and the lower part connected with magnets. This should sound familiar and wasn’t the problem.
The issue was that I did not want 1 big hose attached to it because:
It decreases the usable size of your table
And it only sucks from one side
So I had connected 3 pieces of flex (you know the flexible PVC pipe in which you can run electrical conduit) connect to it, and these again connect to my shop vac. When turned on it failed because it made a very high pitched whistling noise (even louder then the VAC an the router) and it would almost not pick up any dust. Only when right in front of it, otherwise not. So I'm back to making a traditional dust shoe. They must have made the design that way for a reason :-).
That’s pretty neat. I’m surprised, but it opens in my phone’s browser window!
Agreed, I've never used that before! It's a function of Fusion360, I didn't even have to upload anything myself.
DeWalt make an adapter like that. IIRC, it sort of fits the 1 1/8″ hose. I didn’t like it got the reason you mentioned, it gets blocked when you lower the bit.
I found that product after I started printing, but figured I'd stick it to the man and make my own :)
A garden hose is really too small for this application though. The area of the hose is really important. Your vac won’t be able to pull enough air through there.
Hm, isn't the pressure of the system a function of the surface area of the hose? If this were positive pressure instead of negative, a smaller diameter would mean a higher pressure. As a thought experiment, if the vacuum hose was 2ft across, the suction would be very diffuse. I could be thinking about it all wrong though.
I’m also convinced that a good dust collection needs to have the bristles to stop the high speed chips. Then the vac can pick them up. The design I’m using does ok, except for the chips that escape.
I have considered it, but for now wanted something that can minimize fine dust, and I wasn't sure why one would use bristles. Chip collection is a good use case though!
On a side note, shouldn’t your furnace have a filter that would remove the chips?
We do, but I’m pretty sure the filter is before the garage.
House -> Filter -> Furnace in Garage -> House
I could have the HVAC direction incorrect in my head, but even so, there is a fresh filter, and we could smell hardboard everywhere. I was actually thinking another solution would be to mount another filter to the furnace intake, but I don’t want to hack the heating system if I can help it.
On a side side note, congratulations on the pregnant wife! We are expecting our second in January.
Awesome! This is our first, due March 20th. Have you found good CNC projects for children? Rocking horses, cribs, etc?
w.r.t. pressure: You’re right about the pressure, but a 10-foot hose that’s 1/2in ID, and flexible is going to cause so much resistance that the vac just won’t suck through it. Dust collection impellers are designed to move a certain amount of air at a certain pressure. If the airflow is restricted, they won’t have as much air to push around, so they won’t be doing much but spinning a propeller in a vacuum. That’s if they are sealed well, and are actually reducing pressure, but they probably aren’t, they are probably just leaking everywhere else. You really want as much airflow as possible (not airspeed) at the tool. That will suck in as much of the really tiny dust particles as possible. A lot of woodworkers (who aren’t exactly engineers, a lot of the time) try to make sure the area of the vacuum stays constant. So if they have a massive 6" diameter hose, and want to connect a 4" tool, they will have another 4" hose open somewhere else (the area of 2x 4" circles is about the same as 1x6" circle).
w.r.t. 3/2/1 hoses: I don’t think there’s a big problem with having just one air inlet. I think of it like an ATX computer case, where all fans are oriented to push air in the front and out the top/back. If you have air flowing from the passive side, across the bit, to the vac side, then as long as the chips are moving slow enough, they will move with the air. The 2x ports I’ve seen (like on Frank Howarth’s beast) are pretty effective, so maybe the airflow is more from the front/back, and out to the sides. It’s a little hard to compare, because I’m pretty sure I’d need an electrician just to plug in his dust collector in my garage. It might be splitting hairs, really, the air currents have to be going nuts in that area.
Did you see my dust collector? https://www.thingiverse.com/thing:2477060 I think it works pretty well, at least for the really fine dust. The big stuff tends to shoot out pretty fast to the outside. Even taping some paper on the outside would probably help with that.
Ha, I actually did find your design! I didn’t realize it was you or I would have asked you about it directly, but your comment about getting the carriage stuck to the worksurface sounded scary. Is it actually an issue?
I was thinking of designing something like this, but one that follows the outer radius of the 611 shaft. You mentioned putting tracks to the router, but I don’t really understand what you mean by that.
What if we combined the plate I made with your dust collector, so there’s a airway running to the plate? That way the primary suction is on your part, but there’s an relief through the router area if it were needed. Am I crazy? Terrible ASCII sideview included.
^vac
| | | |
your dust collector> | ===== \ | <611 shaft
/ \ | | |
------------------------------ <mdf
! <bit
Thanks for the stepstool design, that looks great!
This is the dxf of the 611 plate. If you cut channels (partially through, not all the way) in red, and left the router dust vent open, then the air would/could go past the router, through the channels, and out the vac.
It has stuck twice for me. Now, I just make sure that the router collet is down enough that I don’t need to get the plate too close (within 1/2 inch or so) of the work.
You could try to combine them, but you could still get it stuck. Maybe some cuts out to the edges would relieve pressure if it got too close to the work. The other hard thing is that there really isn’t much room in there. It seems like there should be, but it’s quite tight.
Ah, I get what you mean. Some channels would help, yea.
Maybe eliminating sticking would just be a matter of having a relief valve off your port. a small hole on the top side which sucks in a bit of air all the time. That way, if the carriage were affected by high suction, the resistance would cause the top hole to work harder, reliving that suction. Maybe even a small door that works as an automatic baffle? No idea if that is viable, or if it ruins the whole point of the vacuum.
I’ll be thinking about this one! Let me know if you’d like to do a CAD collaboration on it.
In general the way a vacuum works is that the end of your hose away from the impeller fills in with ambient air, so at one atmosphere of pressure. The impeller can try all it wants to, but air will only flow at that rate. When the impeller is reversed and you provide positive pressure to the hose, it will usually be at a much higher pressure and will move a much higher volume of air. That’s the primary reason that smaller tubes move so much less under a vacuum than larger tubes even though they can move many times as much under pressure. There are also fluid dynamics in play where the inner surface of the tube forces an area of lower velocity air due to friction, and that area is a larger percentage of the total cross section in a small tube than in a large tube, but that’s pretty minimal in relation to the differential pressure.
Thanks for that explanation, Bill! I’ve never thought about it that way, but it makes a lot of sense. You can move up from 1 atmosphere to as many as you like, but you can’t go as far down, because a complete vacuum would be the limit.
Well, causes too much turbulence… You want a little or else things tend to stick to the surface. We used to sand blast the interior of the intake and exhaust manifolds when porting a head, cause if we left them shiny droplets would stick to them and build up. If the surfaces were just a little rough then they’d flow right past.
I rode an experimental surfboard, that had dimples all over the bottom. The theory was to create pockets of turbulence to decrease to boundary layer friction trying to increase speed.
Other than the design, not memorable. I have some H2 fins from FCS that are amazing on a steep face. Once the 3rd fin comes out of the water (leaving the side and trailing fin in) the board takes off, I was shocked at the difference. Hand shapers are still around but I feel like a ton of money is going into board Research design and there are a ton of cnc’d boards and fins out there now.
Heck, if the surfboard had been truly effective, it would have just sunk as soon as you went to get on… They kind of need some support off that water after all. Their problem was trying to reduce the friction along the surface of the board without reducing it perpendicular to the board…
Their problem was trying to reduce the friction along the surface of the board without reducing it perpendicular to the board…