New "high tech" dust foot, opinions?

[Sk8MFG]

I have a friend in town who works with plastics. Injection molding, 3d printing, thermoform etc etc...

We got to talking about my dust collection setup on the bot, which is a kent style boot. It works reasonably well, but has huge room for improvement.

After a few brain storming sessions, we've come up with a design for a new boot which will be going on my bot.

The boot has a 4" outlet, clamps to the base of the spindle and can be matched to different spindle diameters. The skirt is mounted to the boot with magnets to aid in easy tool change. The brush is also easily replicable.

This design focuses airflow around the tool which will reduce the loss of vacuum when the skirt hangs over an edge etc. It should really suck.

Once we're done testing on my bot, we may make some more. I'd love to get some feedback on it. Any suggestions or comments would be welcome.

25214

[Justin G]

I made my own dust foot using acrylic before finding the kent shoe on the forum. It was the exact same concept: magnets, clamps to the spindle, removable brush skirt, etc. Learned a few things before buying my kent shoe. The dust foot that came with my shopbot was not as awesome as the rest of my big blue. Shopbot has since updated the design and has the new ones for sale, they LOOK awesome, but personally have no experience.

One thing about the kent is that it is tight in some area and not in others. I position my clamps perpendicular to the long axis of the dust shoe so that when I am doing a profile cut, the "housing" of the dust shoe does not hit my rockler clamps that are about 2 1/2" high. I think the housing body should be MUCH tighter to the spindle with the brushes protruding out at an angle. Since they are flexible, they can accommodate larger diameter bits and when they brush against clamps or other obstructions, the brush will fold naturally. I'm thinking something like a 45 degree angle.

The hose should definitely go up in front of the spindle in my opinion. With it going to the rear, you lose Z travel or at least have to think about it, and that is one more thing of 1,000. I had an idea to make a tight fitting shoe that would have the hose run around the body of the spindle so that is actually sucked air THROUGH the cooling vents. You would have to reverse your cooling fan, or disable it while DC was running, but I think the added air would help to cool the spindle as well. Small chicken wire could prevent larger chunks from getting lodged in there. If the brushes were large enough to fit a 2 1/2" diameter bit with some slight added clearence, I would be happy.

Also, I made an arm which connects from the back bracket and wraps around to the front, this takes the weight bearing off of the Z axis and has it resting on the Y car. Which should be a lot less gravity to contend with. That should be included, again IMO. I'll post a picture shortly.

Sometimes with doing engraving onto a 3d work, I have to go deep into the carving and I just cant do that with any high angle walls, or tight spaces with the kent. Another reason to make it tighter to the spindle. Of course I could remove the foot temporarily, but I dont and won't and usually just hope It doesn't crash into anything, finger lays in wait on the spacebar...


here is the new dust foot:
http://www.shopbottools.com/ShopBotDocs/files/SBG%2000326%20PRS%20Dust%20foot%20install%202014%2 010%2029.pdf

[Justin G]

2521525216252172521825219

pictures of the arm as promised. Its not pretty but works for me.

[Sk8MFG]

Great, this is just the kind of feedback we need. Keep it coming!

Your setup looks very similar to my current one. I'll pitch the idea of having the port going vertically and see what we can do. Only problem I see of going up the front and tightening it to the body is it would be limited to only a few spindles. With the duct going out back, it would fit on any spindle.

The image I posted doesn't really show the clearance too well, but it should provide more clearance than your(my) current setup. The duct is set above where a kent main plate would be. As for pitching the brushes outwards, that may be a good way to keep the brushes from getting cut up. We will be playing with different brushes, most likely using a stiffer brush to keep the bristles from being sucked into the tool.
The diameter of the brush would be able to fit any bit you can mount. I have a large cove bit, which will be used with this boot. I think it's 4" wide or so.

I'd love to be able to make a few of these for fellow botters. I have a feeling it's going to be quite the nice bit of kit, and won't break the bank.

[Kyle Stapleton]

Do you think this would fit on a bot with air drills?

[donclifton]

I made some out of MDF, Because the brush is much smaller I get more suction. I have inserts to raise and lower my brush for longer or shorter bits.
Thanks
Don
http://www.talkshopbot.com/forum/attachment.php?attachmentid=25220&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=25221&stc=1

[Sk8MFG]

Do you think this would fit on a bot with air drills?

On a PRS with an air drill, if the dust port was coming out the back... probably? If we had it come out the front like the photo below, I don't think so. *edit. I suppose using this configuration you could have the duct off to the side of the spindle vs straight ahead. That may clear an air drill.

25235


I made some out of MDF, Because the brush is much smaller I get more suction. I have inserts to raise and lower my brush for longer or shorter bits.
Thanks
Don

Yep, very similar principle. Reduce the area to increase the suck. We'll be running some simulations as well as lots of testing to see how much of an improvement in air speed our new design gets. See how it stacks up to a kent style, and one like your's Don.

[srwtlc]

I like your proto. Some thoughts/opinions... I prefer it to come out the back because of how my tool is set up and for ease of tool changes from the front (front for me is the spindle side). Coming out the front along with the hose, puts it in the way of tool changes. Having it attached to a drop bar in the way that SB does allows for more clearance whereas mounted on the spindle nose takes away some of that clearance distance. One way to gain some extra clearance is to make the connection on the foot be oval shaped. On the older SB ones, they would flatten the 3" hose and shove it in the back of the foot. This was a poor way of attaching it and also left a leaky connection. I took a piece of PVC and heated it until I could form it into a flat oval shape that fit into the back of the foot and then sealed it in place with expanding foam. This allowed a 3" hose to be easily slipped on and clamped in place. This also allows for full Z lift yet.

If connecting from the front, it will not allow drills to be used (SB's new one apparently wasn't designed with that in mind either). Coming from the side will interfere at each table leg location and if on the motor side, will have to go out and around it. Might be able to get away with a angled connection that would allow for a drill attachment and clear the legs.

You could use a long drop bar in same way that the new SB one does. That alone alleviates the small thumb screw down/behind/underneath that is hard to get at and not always in the right position.

Here's a shot of my oval PVC.http://www.talkshopbot.com/forum/attachment.php?attachmentid=25236&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=25237&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=25240&stc=1

[coryatjohn]

I would have to go with the "hose in the front" crowd. I originally had the (crappy) SB dust foot and tried using it for a while but having the hose come out the back just kept being an issue. Once I installed the Kent foot, with the hose vertically mounted in the front, it worked out great. I have a 5" hose from the DC and a 4" hose coming out of the foot. The smaller hose slides in the larger one (with a gasket at the top of the smaller) so the joint is quite flexible and doesn't have to bend to get longer or shorter. This works quite well with my 12" Z machine. It also offers very little resistance to the Z axis.

One thing that may be an issue is the volume of air that can be moved if you constrict the opening of the host like you have in your prototype. The Kent design maximizes the air flow. I have a wicked good dust collector so it sucks mighty and I'd hate to have anything get in the way of that flow. Also, obstructions to the flow would cause one big howl. I don't need any more noise in my shop then I already have.

I think the Kent design is pretty good. I've had no problems changing bits or having it collide with clamps. I have both the 2 and 3" brushes with an extension so I can adjust it to however I need for a particular cut. I agree that 3D work is a problem, especially using the indexer. I just go without dust collection and use a manual vacuum to keep things from getting too messy. I don't do a lot of that so it's not a problem.

[kurt_rose]

Very interesting to say the least. I work with a lot of Extira and we all know how toxic that is. Better dust collection always gets my attention. Looking forward to seeing where you go with this. I've been very happy with my Kent, but there is always room for improvement.

[adrianm]

Much better to have the hose in front IMO. I'm not a fan of the squashed inlet type solutions. If the brush and base disconnect via magnets like the Kent shoe then changing the bit is not a problem and far easier than the SB solution. To be honest the only issue I've ever had with my Kent shoe is cutting right at the front of the table where the air flow is lost off the edge of the table. Other than that it's absolutely perfect.

[Sk8MFG]

To be honest the only issue I've ever had with my Kent shoe is cutting right at the front of the table where the air flow is lost off the edge of the table.

I do a lot of 3d cutting, and this is the main reason I'm working on this new foot. A soon as my current foot hangs off the edge, or the surface falls away dust is simply launched across the table with little of it being sucked up.

I'll take all your suggestions so far and see what we can come up with in terms of revisions.

Keep giving me info! This is great.

As for a price point, what would you be willing to "pay" for a complete foot like this? We aren't sure how much it would cost to make. Fairly expensive if I only make one for myself with the price dropping sharply if we actually made these as a product.

[Burkhardt]

One thing I noticed with my own experiments, is that mostly vertical air flow is not that effective. The rotating bit will sling particles horizontally across the surface and it takes deceleration over a minimum distance to slow them down sufficiently to reverse course and go up into the DC. That means a narrow gap around the foot will have only a very short area of high horizontal air velocity and the particles may just zoom through (especially heavier ones of plastic or metal). A radially wider channel seems to work better, e.g. a wider brush or a flat rimmed foot.

I still need to make some permanent modifications for my own dust foot along these lines. Right now it is only a concentric shroud around the spindle that moves up and down and a sliding extension that is stationary in height relative to the material. Works kind of O.k. but my DC is only 1 hp and some heavier particles escape. However one advantage is that I can slide the extension up for access to the collet and, the air stream provides \ample cooling for my (technically water cooled) spindle

[jerry_stanek]

Myself I like a shoe that doesn't go up and down with the spindle. I have mine so I set it to the material and it stays there while the spindle moves up and down. also I only have a 3.5 diameter brush that gives me a good pickup even on the edges of the bot. it is a back fed but not the squishy hose.

[coryatjohn]

I've thought about what would be a more ideal solution for a dust foot and it seems that adding a flat jet of air from the back of the foot blowing to the front would improve chip recovery and also keep more chips out of the curf. The shape of the Kent foot seems pretty good. If I'm working close to the front of the machine, the chips do go flying when the vacuum is off the table edge but most of the time, I just keep my work in about a foot to prevent that.

While your new design certainly looks cool and might avoid the issues of clamp clearance, the restricted flow due to the constrained dust connection would make it less useful. The reason the Kent foot is shaped the way it is probably has a lot to do with high flow rate for the dust collector. I doubt that can be changed much without restricting the flow a lot.

If you could build a better mousetrap than the Kent design, I'd pay $100 for it. I'd really have to be convinced though. I like the Kent design.

[gundog]

I think your design would work better if the hose port came in at a 45* angle rather than straight down.

[phil_o]

I designed and made the dust shoe shown in the attached photos. This one is vacuum formed. Like yours it has a smaller opening which provides better suction where it's needed. I also think the angle at the opposite end of the shoe provides better air flow. I hope you are successful in building a better dust shoe.

Phil

[curtiss]

Could you make the front half of the foot "hinge out of the way" so you can get the wrenches to the router easier ?

[Sk8MFG]

I designed and made the dust shoe shown in the attached photos. This one is vacuum formed. Like yours it has a smaller opening which provides better suction where it's needed. I also think the angle at the opposite end of the shoe provides better air flow. I hope you are successful in building a better dust shoe.
Phil

Very nice. Good to hear it has improved performance, at least we are on the right track. Ours is moulded plastic, not thermo formed. It will let us do some fairly complex shapes.


Could you make the front half of the foot "hinge out of the way" so you can get the wrenches to the router easier ?

No need :)
The brush is attached with magnets and is easily removable. The base which attaches to the spindle is well above the nut, shouldn't be any problem with getting tools in there.

[gc3]

dust shoe discussion is a mute point...

unless the dc has needed cfm no matter the design...

12mm bit hogging out a panel @ 9mm doc @ 6100mm/min makes for a nice rooster tail of chips

[Burkhardt]

Well, yes and no. Like the old automotive adage "there is not replacement for displacement" you can say "there is no replacement for volume flow". If you have a 20 hp tornado machine the dust shoe may not make much of a difference as long as you keep the DC hose nearby. But, especially when you are power limited, the design of the dust shoe is the difference between useless and O.K. or maybe even "good". For that matter, I don't worry about 12mm bits, 9mm doc and 6 m/min with my 3hp spindle. I guess I could do that in foam, maybe :)

[coryatjohn]

I have an Oneida 2HP cyclone and it really sucks. Most of the time, I find the Kent foot and a 5" hose is a pretty good combination to rid my shop of any trace of chips and dust. I machine a lot of plastic and this setup is perfect. I rarely have to clean up anything after 8 hours of cutting. I think the only improvement I would add is the air jet to get the chips out of the curf and move things into the vacuum flow. I would welcome a better mousetrap but I would need proof it was worth the cost and trouble.

[myxpykalix]

The issue i've had with dust collection over the years is the dust hoods running into clamps and breaking or the "unknown" of not being able to see where your bit is cutting because it is hidden under the brushes.

I don't use dust collection as much because i like to see what's happening before catastrophe. I do use breathing protection instead..

The problem i see is that by the time your average dust collector reaches the router bit it's suction has been deminished over the length of hose.

I have been thinking about some type of U shaped dust hood where you could see your bit cutting, and mounted somewhere on the carriage would be some type of small powerful vacumn that would act as a strong suction primer to make up for the loss of vacumn and maybe some type of air sprayer from the front that would push the dust to the back of the dust shoe that is open in front and act as a "air wall".
Knowing almost nothing about vacumn and suction, air pressure, ect
am I just way off base here?

[Designer]

I am new to CNC use, but I think there is room for improvement in dust boots. Mine gets in the way when changing the bit and zeroing the Z axis. Taking it off vertically presents some difficulty in getting it past the bit. I am thinking about a two piece boot. The brush section should make up for any slight mismatch. The front could have a fit that mates to the back and some simple locking feature, or it could just slide off. I'll try to come up with something in 3D and post it via a .step file if you are interested.

[Ger21]

One thing I noticed with my own experiments, is that mostly vertical air flow is not that effective. The rotating bit will sling particles horizontally across the surface and it takes deceleration over a minimum distance to slow them down sufficiently to reverse course and go up into the DC. That means a narrow gap around the foot will have only a very short area of high horizontal air velocity and the particles may just zoom through (especially heavier ones of plastic or metal).

That's the main purpose of the brush. To stop flying chips and contain them until they can get sucked into the hose.

First, a 1HP collector is not really adequate for CNC use. I'd consider 2HP to be a minimum. I actually have a 1HP dust collector connected to my CNC. I also have a 2HP Harbor freight collector, and it is at least twice as powerful.

Dust shoes are very dependent on the specific application. Or more importantly, brush length.

For someone cutting sheet goods with a vacuum table, a 1-1/2 to 2" long brush works very well. The bottom of the bristles should be about 1/8" below the tool tip. This forms a "seal" against your spoilboard and should allow collection of just about all airborne dust, if you have enough CFM. But there will still be some dust when you cut along the edge of the spoilboard, effectively breaking the seal. On our Morbidelli at work, I can trim 1/2" off of a 3/4" sheet of MDF or particle board, at 1200ipm (20 ips), with a 1/2" compression bit, and there is no dust.

Anyone using tall clamps will always have problems. Same thing for deep 3D carvings. In those cases, long brushes (~4-5") are probably your best option.

If you can allow the brush to form a seal around the work, and use a 2HP or larger dust collector, with at least a 4" hose, you'll get pretty good dust collection.

[Sk8MFG]

We've been tweaking the design constantly using all your feedback.

We're not too concerned about the transition between the round 4" duct to the oval passage through the foot. The maths say the increase in velocity so close to the cutter will offset any reduction in total airflow (not much). The first real world prototype will shows us if this actually happens.

For those worried about running the foot into things. We may be building it out of semi-ridged or flexible urethane. This will let the boot "give" a bit when it makes contact with things which don't normally move (clamps, workpiece etc).

Still trying to figure out how to incorporate a way to view the cutter head while it is going. Maybe make the whole thing see-through!

[gc3]

would this shoe work for this...

[srwtlc]

Gene, for what you do and for as much of it that you do, I think I'd just park the machine in a big wind tunnel and let 'er rip! Operator safety harnesses required. ;-)

[Brady Watson]

If you are just doing sheet goods, the SB or Kent foot works fine. For 3D work, unless it is shallow, dust collection is a no-go. Those who cut it on a regular basis will tell you that aside from roughing, it "ain't gonna work". There isn't enough brush length to compensate for the up & down of the Z, but the issue you run into is that the foot actually gets hung up on things like the last pic Gene shows in his examples. Since you are mostly cutting chips and not rooster-tailing when using a ball during finishing, it isn't that bad to just vacuum up the chips.

Kudos to those making their own dust foot - you are smart enough to realize you own a CNC with infinite possibilities...How ya think Kent does it? I think he realized he could capitalize on the laziness of users...and there appears to be a lot of them out there. Good for him.

-B

[myxpykalix]

I think he realized he could capitalize on the laziness of users...and there appears to be a lot of them out there. Good for him.


Hey... I resemble that remark! lol

Actually he makes a good point, in that, I have stopped using my dust boot because i don't like to not be able to see where i'm cutting in order to avoid catastrophe before it happens.
I had mentioned earlier about a open faced dust boot with a air mist type thing to keep the chips within the confines for the vacumn to suck it up but....

I thought about a U shaped boot with bristles around the sides and back and in the front have a plexiglass window with some LED lights to allow you to see the bit, light it up and maintain the suction. Sound feasible?

[adrianm]

It's not always "laziness" it's economics as well. I'd rather spend my spare time doing things other than working on the CNC and if I designed and made one in the working day it would have cost me far more in lost production time than I paid Kent.

[gc3]

18 months or so ago...ceiling panel in process, start of roughing pass 1st photo, 2nd final of roughing pass... dust shoe, 2hp collector useless...

el nino year...predicted 19 events, #2 Blanca tracking towards us on sunday as a cat 3

[Sk8MFG]

would this shoe work for this...

Hmm, it may work quite well. In theory at least. With the skirt being so small in diameter and the rest of the body above the end of the spindle, you should have enough clearance to get in there.

One goal with this foot is to maximize what you have in terms of dust collection. I have the bot hooked up to a 3hp dust collector. With my current foot, it just doesn't have the flow in the right place.

Once again, thanks for all the input guys. Hopefully we can make a prototype in the next month or so.

[Sk8MFG]

We have a new prototype drawn up. Should take care of any clearance issues.
Opened up the air flow vs our previous versions.
25408

Any more input on this version?
We're getting close to building the first prototype.

[coryatjohn]

That looks pretty good. It appears to be side agnostic. I assume it can be mounted on the front. Correct?

[gundog]

That looks good. I need an automated version for my tool changer spindle so it can move out of the way durring tool changes.


We have a new prototype drawn up. Should take care of any clearance issues.
Opened up the air flow vs our previous versions.
http://www.talkshopbot.com/forum/attachment.php?attachmentid=25408&stc=1

Any more input on this version?
We're getting close to building the first prototype.

[Sk8MFG]

That looks pretty good. It appears to be side agnostic. I assume it can be mounted on the front. Correct?

Yes, it can be mounted at any point around the spindle.


That looks good. I need an automated version for my tool changer spindle so it can move out of the way durring tool changes.

Hmmmm, I'll pitch the idea. With the way it is built, it may be possible to exchange the "standard" lower body/brush with a mechanized version.

[Sk8MFG]

A couple of follow up notes provided my my friend...
• This foot can be mounted in the same way as the ShopBot; he made a little modification making install easy for those that already have the ShopBot version
• The foot is made of a hard rubber so that if it is bumped into something, the foot and/or bumped object will not be destroyed

He is planning to make a foot for me and anyone else in the group interested in purchasing one. US$100ea for the first small batch only. This includes the boot, brush foot and strip brush material. Those in the first batch will get a say on the design before it is 100% finalized (and a bonus offer if there enough interest). This will help us refine the design even more. We are hoping to make 10-20 in the first batch to cover mold costs. Delivery would be 2-4 weeks depend on how many design / part changes are needed.

PM me your email if you are even mildly interested in participating.

[Bob Eustace]

As a loyal Kent user the big hurdle for me is you cant see the cutter. The Kent is clear perspex on top.

[donek]

This is the high tech solution. Never used one, but sounds like the device that would really solve the problem for those that are working with dangerous materials.
http://www.guhdoonline.com/shop/airpro-collet-nut/airpro-dust-extraction-nut/
file:///C:/Users/Owner/Downloads/DOK_MBR_LEUCO-Aerotech.pdf
https://youtu.be/eY-MwagXpds

[pappybaynes]

This is the high tech solution. Never used one, but sounds like the device that would really solve the problem for those that are working with dangerous materials.
http://www.guhdoonline.com/shop/airpro-collet-nut/airpro-dust-extraction-nut/
file:///C:/Users/Owner/Downloads/DOK_MBR_LEUCO-Aerotech.pdf
https://youtu.be/eY-MwagXpds
For a $1000.00 it's not only high tech but high priced!
Dick

[donclifton]

I think it was $100 dollars. A lot cheaper than the Kent.
Don

[GeneMpls]

$1,000.00 + $5.04 shipping on Amazon- I did see it for $900 somewhere.

[MogulTx]

Yes... a bit of a side track on the high tech dust foot , but chances are that I am not going to be paying 1000 for a spindle nut with a cool wing technology cut on it!!! Whoever thought that was going to be a good market (at THAT price) did not think it through that well!

[jerry_stanek]

I see it is for Er 32 or 40 collets. We could use one at the shop I worked for running a Biesse with multiple heads and a really large dust hood. they may go for it as the hood doesn't do a very good job.

[Sk8MFG]

Yes... a bit of a side track on the high tech dust foot , but chances are that I am not going to be paying 1000 for a spindle nut with a cool wing technology cut on it!!! Whoever thought that was going to be a good market (at THAT price) did not think it through that well!

I doubt their target is us botters. While a neat idea, I wouldn't be able to justify the price in my business. But them big guys, running non stop 24/7.. I bet it would pay for itself pretty quickly.


Ohhh... if only I had an unlimited budget for cool toys :(

We've had several folks express interest in the project.
If you have any interest in the project, please PM me your email address.

[jerry_stanek]

Like I said it would cut down a lot on the amount of clean up they do. They run their Biesse's about 6 hours a day but they could cut that down I used to run their pod and rail but it had a out feed conveyor to get rid of the waste.

[donclifton]

Must be something wrong with my screen, Mine said first batch at $100. where do you all see $1000.
Don

[steve_g]

Don…
For the design prototype SK8MFG is developing… $100.00 is correct!
The topic got changed and $1000.00 solutions were linked to.
SG

[Sk8MFG]

As a loyal Kent user the big hurdle for me is you cant see the cutter. The Kent is clear perspex on top.

Thanks Bob,

I'm trying to put myself in your shoes. How does the clear top side help in your particular work flow?

We did some brainstorming regarding visibility issues. To paraphrase the designer:
1. Fixed boot is sloped upward exposing cutter, when viewing directly from the front. You should no longer have to bend over so much if running without the brush ring.
2. The brush ring uses a slide-in brush. If you need better visibility for particular operations, you can leave part of the brush strip out.
The brush ring will also be available separately.
3. There is a clear PVC strip than can be mixed and matched with the strip brush. You can then see thru the "brush"

Thanks all,