New dust hood and one way to advertise.

[knight_toolworks]

I have wanted to replace the dust shroud for a long time. It does not have enough depth and when I cut 1.5” deep it does not touch the wood. At first (I could adjust it) but then I would have to change it back and it is a bear to screw around with. I wanted better airflow and something that does not clog up with splinters. Quite often mine gets jammed up in the middle of a cut and removes nothing. Plus I wanted something that was easier to get around when changing bits.
So with some idea’s from a fellow on the list I cam up with this design. After I added the brushes I had to change it a bit. The bracket needed a little more then ¾” clearance to keep from hitting everything and I had to move it back against the hose attachment to get the back to clear the z frame. I was not sure how I was going to build it and I only ordered 3’ of brush and bracket so I ran out. I will get more money or Tuesday. .this setup works well though the aluminum track lets the brushes slide so it needed crimping.
The materials were bought from mcmaster under strip brush.
It only takes seconds to loosen the nuts and remove the front. Far easier then reaching under the normal shroud or worse yet removing it.
I make wooden hand planes for somewhat of a living. I have them in wood stores around town. Well this will make the owners happy and get me more attention. They have been good about recommending me to their customers.



6697

6698

6699

6700

[thewoodcrafter]

Nice.
I made one just like it from wood and plexi but I found when I was cutting near the end and edge of the table the vacuum was poor. So I blanked off under the hose inlet and moved the brushes closer to the bit from the hose end. The brush lengths are about the same, about 5" square. The vacuum was much better.

[knight_toolworks]

yes I don't like the hose so far away. it would be great right in front.
but I am not sure how you did what you did got a picture?
I could have knocked 1" in width off after the fact . but I think this will keep dust from getting into the air. using a roughing bit always leaves a fair amount of dust in the cutout. I think if I had the hose in front that would get sucked up. but then it would be a pain and in the way.
I have been wondering about using a round brush that fits over the spindle with a shopvac. something about 4" diameter.

[nschlee]

Steve you could use Nylon Draw Latches instead of the straps & bolts, this way you can change bits even quicker & you don't have to worry about nuts coming loose. You may need to add 2 registration studs & holes for alignment.
McMasters item# 1525A31 page 2897

Neal

[knight_toolworks]

I actually thought of going that way at first. and I thought it would be a hassle to make it work well and now I know it may have been a problem getting in the way. they would need to be on the sides. well this is the first one I am sure I will have more idea's now that I have made one. I was kind of winging this one.
I would like to make it smaller but it would have to be tapered since the brushes would not go aroudn a curve.

[knight_toolworks]

I am now thinking of making one that has the hose say on the left right beside the bit. so it is easy to remove the front for bit changing but gets the airflow right by the source.

[dewey_dog]

Steve, Drill and tap the aluminum so the brush does not move and it also facilitates changing them.

[knight_toolworks]

good idea. today if I get the rest of the brush material I will modify this one so the hose is on the left but it will be attached to the main body so I can remove the front with no problem.

[henrik_o]

This is all very interesting. I have been thinking about making my own dust hood.

I tolerate the current one, it is surprisingly effective, but there's a few things that makes me consider a light DIY project.

1) I don't like the fact that it moves with the Z. That's great for 3D work, but 99% of what we do is panels, so I'd much rather have a design that stayed at a fixed Z.

2) It always gets in the way of bit change. With a fixed Z, that problem is gone.

3) The garotting of the hose is rather atrocious. That kills a lot of flow right there and is perhaps my biggest problem with it from a generic design POV, I don't understand why. Also, the opening for the z axis on top seems way too large, though I can see why that was designed for versatility (many different possible routers/spindles) etc. Additionally, it just feels too large in terms of volume when compared to the air flow vector. First you strangle it, and then it expands to that volume, why?

Ok, I'm not an air/liquids engineer, so I could be talking out of my hat, but that's my hunch so far.

Good news is that I have located an almost perfect ready made object for the hulk of a new dust foot; you probably won't believe this but it's the clear plastic lid for a cheese preserving box, $5. The volume is a bit larger than I'd like, but can possibly be reduced, my only reservation is that I don't know if the plastic machines well or if it's the brittle kind that just cracks apart when you try to do anything with it. With some tinkering I should be able to get a non-garotted hose very close to the spindle head, then adding some flanged flexible plastic sheet like what's on the current dust foot to the bottom and possibly a bit of it in the z axis opening.

If this works well, I might try adding two 4mm compressed air spray nozzles, one for X and one for Y, pointed at the bit. I've tried this a little and a continuos spray of around 2-2.5 bar should clean out even the hardest packed downspiral kerf.

If I ever get around to it in the first place: again, the original foot does work surprisingly well IMO.

[henrik_o]

Here we go;


6701

I haven't quite figured out how to attach it to the gantry, but that should not be that big a problem.

[knight_toolworks]

after looking at the machine there is no way to get a 4" hose to the side of the dust hood. even a 3" hose is too tight.
it will have to come in from the front. then it needs to be gotten out of the way for bit changes. I kind of like the idea of it not moving but that would me for me I would have to make it adjustable since I cut things that vary in height. from 1/8" off the table to 3"

[bcammack]

You can do interesting things with PVC pipe unions if you have a spindle...

[ed_lang]

Brett,

I have a spindle and would love to see some pictures of this "interesting thing" you speak of.

:-)

[Gary Campbell]

Henrik...
You are coming precariously close to "patent infringement" with my, so far only imagined, dust foot design. (big smile) The main similarity is a full diameter hose approaching from the rear as in your drawing. It seems that I am not the only one that noticed the similarity in size between the "leak" at the Z and the restriction at the hose connection. Please post progress.
Gary

[harryball]

I did this... http://www.talkshopbot.com/forum/messages/28/21384.html?1181007457

I love the new position so far as functionality and would do it again even if I didn't need the extra Z height. It just works so much better.

The 4" hose could work coming in from the top but I'd need a new dust foot. The factory dust foot with the metal plate removed and raised allows me to use only a "slightly" flattened 4" hose. I have atleast twice the hose area if not triple the factory arrangement. I've been running this since May and it went through the brunt of cutting parts for 200 bat houses as well. Still doing very well. I'm going to add brushes to the bottom instead of plastic... eventually.

Robert

[thewoodcrafter]

6702
These are a few pictures I took today of my mod to a shoe.
The suction is now way better with the brushes close to the bit.

[thewoodcrafter]

6703


6704

The shoe is now part of the vacuum system.
The old design I had the brushes around the whole outside of the shoe. When cutting near the edge of the table vacuum was nil.

[knight_toolworks]

I like your idea. I take it that it is held in place and the spindle lowers down into it?

[thewoodcrafter]

The shoe is held with 2 full extension slides, one has a spring pulling up. In the second photo you can see a piece of allthread that pushes down on the shoe as the Z moves down. The shoe movement is about 2". As the spindle moves up the shoe stops. I can pull the spindle out by about 4" for bit changes. The allthread is attached to the Z and the shoe stop going up when the vacuum fitting hits the Y carriage roller.
I wanted something like you made but with 2 Z's I found I would have the reach around the spindle ( the 2 Z's face each other) to change the bit. That was awkward. Retractable seemed like the way to go.

[henrik_o]

Gary,

Lawyer up!


Progress:


6705

The new dust foot in front of the old. I am still tinkering a bit with the AOA of the hose inlet.


6706

Old and new side by side.

The new one is almost finished, what remains is some tinkering and attachment to the gantry.

Materials & Equipment used so far:

1 old dustfoot
1 heat gun
1 sharp knife
1 powerdrill; with 1 each of 3mm drill, 6mm drill, 100mm sawdrill
2 nuts (M4 iirc)
1 ordinary spoon
2 clamps
1 hose connector (I used metal, could have used PVC)
1 serving of a good glue (I used transparent MS Polymer)

(Optional: band saw and some scrap wood)

Time:

About an hour and a half: a lot of that was wasted trying to freehand the thermoforming -- after I cut out some wood scraps on the band saw to help define angles and shapes it was a snap, I got my angles and could smooth out the shape with the spoon. I also wasted time trying to figure out how I would get rid of the inevitable excess material in the basic shape which formed large bulges, after I solved that it was an easy ride. When I convert the other old dustfoot, I think half an hour is entirely realistic.

---^*^---

I'll post progress on the attachment side of things, and if anyone is interested in a more detailed work description I could post that.

All in all, I haven't tried it out on the Shopbot yet, so I can't vouch for this being a valid design, but I have tried it freehand just attached to the DC hose and from what I can tell it's got almost perfect vectored suction (still some tinkering with AOA and further smoothing of the top bulge) and a decent distribution of volume. Putting the new dust foot on the table and inserting your hand under where the Z inserts there is a remarkable difference in suction, to say the least.

I think I need to work a bit on the Z inlet however; it is a bit too large for my taste but I'm not entirely sure how to do this in an efficient manner. The collet nut must be allowed to pass, and I'm not sure cutting some flanges into a flexible plastic sheet in a camera shutter-type pattern would stand up to that abuse. The alternative would be to recess the part of the dustfoot where the Z lowers into the material to allow for the collet nut outside the actual dust foot, but that would create an opportunity for crashing into the dust foot and also it would mess up the distribution of volume.

Anyway, it's a good start, we'll see how it works out from here.

[stevem]

It can be done. Two piece, vac formed dust chute with pressure foot for 4" hose.

6707

[henrik_o]

That looks really good Steve. How does the spring mechanism work, more in detail? Is there a brush/flanged skirt underneath?