Show Your Dust Shoe!

[gundog]

My next dust foot will have a 5" hose all the way to the foot. I have designed it and bought the stuff to build it but I would really like to automate it like the one in Gary Campbell's first link. I bought magnets to make a Kent style shoe but I am not sold on the design because I use a lot of long bits and I have a tool changer so moving a portion of the shoe when making a tool change I think is really the way to go.
Mike

[rb99]

My next dust foot will have a 5" hose all the way to the foot. I have designed it and bought the stuff to build it but I would really like to automate it like the one in Gary Campbell's first link. I bought magnets to make a Kent style shoe but I am not sold on the design because I use a lot of long bits and I have a tool changer so moving a portion of the shoe when making a tool change I think is really the way to go.
Mike

Why do you want the 5" to the foot?

[knight_toolworks]

My next dust foot will have a 5" hose all the way to the foot. I have designed it and bought the stuff to build it but I would really like to automate it like the one in Gary Campbell's first link. I bought magnets to make a Kent style shoe but I am not sold on the design because I use a lot of long bits and I have a tool changer so moving a portion of the shoe when making a tool change I think is really the way to go.
Mike

you might have too much air then you end up sucking up the brush. being able to adjust the brush heigh is the best solution I found for long bits.

[gundog]

you might have too much air then you end up sucking up the brush. being able to adjust the brush heigh is the best solution I found for long bits.

The whole point of using an automated dust shoe is to not have a long brush to be sucked underneath this is why I have not built the Kent style with longer brush if you watch the video that Gary posted (the first link) this allows the rear portion to be lower my machine has a tool changer so the only way to get the brush low enough is to use a real long brush (non automated) so that portion does not hit the rack on the tool changer. I have done some CFM testing on my duct work I have to keep a second 4" blast gate open to increase my air flow on the 4" hose going to the router now. I believe I will get better air flow with the 5" hose. I machine plastic not wood on a regular basis and my current system does a poor job of collecting the chips.

When I had my Shop Bot I had an adjustable dust shoe that Gary Campbell had made and it would get almost all of the plastic chips so I know it is possible but the SB did not have a tool changer so adjusting to each length of bit was done at the manual tool change.

[Greybarn]

Here is a picture of Kent Dust Shoe on my PRT. I was cutting 1/2" thick G-10, 12,000 RPM at 30 IPM using a SGS FGR-6 bit. I can't say enough good things about the Kent Dust Shoe. And the FGR-6 bit was really good.Kent Dust Shoe on PRT cutting G-10.jpg

[steve_g]

Thoughts on using a 5” hose to the dust foot…

http://billpentz.com/woodworking/cyc...s.cfm#Airspeed

A certain velocity of air is required to pick up and transport sawdust…

4000 FPM has become an industry standard that is well tested and proven solidly to work to move dust.
3” hose area = 28.27
5” hose area = 78.25 nearly 3X the area of 3” !
Or: 777 CFM for the 3” hose
2166 CFM for the 5” hose

A good 3hp Oneida cyclone draws 1500 cfm…
We haven’t even talked about duct friction loss or SP (static Pressure) needs… or that not only are we collecting sawdust but it has a velocity coming off the bit that must be overcome…
Unless you have an impressive industrial dust collection system, I think you’re asking for trouble with your 5” hose…

SG

[Greybarn]

That's a 4" inch hose on my dust foot. Previously I had a 3" inch. I think the 4" inch does a better job.

[gundog]

Thoughts on using a 5” hose to the dust foot…

http://billpentz.com/woodworking/cyc...s.cfm#Airspeed

A certain velocity of air is required to pick up and transport sawdust…

4000 FPM has become an industry standard that is well tested and proven solidly to work to move dust.
3” hose area = 28.27
5” hose area = 78.25 nearly 3X the area of 3” !
Or: 777 CFM for the 3” hose
2166 CFM for the 5” hose

A good 3hp Oneida cyclone draws 1500 cfm…
We haven’t even talked about duct friction loss or SP (static Pressure) needs… or that not only are we collecting sawdust but it has a velocity coming off the bit that must be overcome…
Unless you have an impressive industrial dust collection system, I think you’re asking for trouble with your 5” hose…

SG

So here is what I know because we measured it at the machine for my system with just my duct open for my dust shoe we had less suction then when I opened an additional 4" duct on the same line it actually picked up velocity. My neighbor did refrigeration and had the meter that is how I know.

[rb99]

When the foot is attached to the router won't any vibration of the foot cause small but visible movement of the router? For example a piece of cutting flies up and hits the foot or a cutoff piece lifts up and temporarily jams the foot...

[steve_g]

“when I opened an additional 4" duct on the same line it actually picked up velocity.”

Yes, I’ve experienced that phenomenon before… I’m told it has to do with the efficiency of a particular fan design. A fan works it’s best in a very narrow CFM range and if “starved” for air, becomes inefficient… At any rate, testing with an anemometer is the best test!
SG