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vacuum table

Posted: Thu Nov 21, 2019 5:22 pm
by Hobbyman2
Years ago in the shop we had a table that had small holes in it maybe 1/16 in or so dia , on the under side there was flat duct work with a vacuum connected to it , when you turned on the vacuum the table actually held down the work project ,flip the reverse switch and the sheet would float like a air hickey table , just wondering if this could adversely effect the motor on a dust collector,, or if any one has tried this .

Re: vacuum table

Posted: Thu Nov 21, 2019 6:52 pm
by reible
I have not connected to a dust collector but have connected to a shop vac. The results were not up to what I wanted and I have not gone back to make a few changes to see if I could improve on what I had.

In particular I needed to seal up my box, it was clear that there were air leaks and they were have an effect. Second I was using my old shop vac which even back in 2009 was old and worn down, I expect that I would see better results now with new equipment that I now have.

I know where the box is but not the peg board pieces so I might just pull this out again and seal the box and make new inserts and have a go with my newer shop vac and see how that goes.

The thread explaining what I did is here:

https://www.shopsmith.com/ss_forum/gene ... t4531.html

Ed

Re: vacuum table

Posted: Thu Nov 21, 2019 7:06 pm
by Hobbyman2
That's what I was trying to decide if a bigger unit would work

Re: vacuum table

Posted: Thu Nov 21, 2019 7:07 pm
by roy_okc
I would be a bit worried about hooking up to the dust collector unless you had a way to let some air through unimpeded. If you use the SS DC, perhaps you just unplug one of the other vents.

You might not get the same amount of theoretical holding power using the DC versus a vacuum, but if the table has any size I bet it would work just fine. With a full vacuum, you get 14.7 PSI of pressure, which works out to over a ton per square foot (14.7 PSI x 144 in^2). While the DC wouldn't pull near full vacuum, you make up for it in size; for instance if it only pulled 1 PSI, you'd still have 144 PSF.

Re: vacuum table

Posted: Thu Nov 21, 2019 7:38 pm
by jsburger
Hobbyman2 wrote:Years ago in the shop we had a table that had small holes in it maybe 1/16 in or so dia , on the under side there was flat duct work with a vacuum connected to it , when you turned on the vacuum the table actually held down the work project ,flip the reverse switch and the sheet would float like a air hickey table , just wondering if this could adversely effect the motor on a dust collector,, or if any one has tried this .
A dust collector and a shop vac are basically the same thing. A motor and an impeller. The only difference is air flow. The air is what puts the load on the motor. If you reduce the amount of air the impeller is moving the load on the motor is reduce and the motor speeds up. That is why when you block the hose on your shop vac the noise increases. It is not working harder it is running faster because the load is reduced. If you run a motor with an impeller in a vacuum there is no load on the motor.

As long as the motor is rated continuous duty it should actually help the motor.

Re: vacuum table

Posted: Thu Nov 21, 2019 8:20 pm
by Hobbyman2
I dont know of any one who has done this on a small scale , other then a few videos , https://www.youtube.com/watch?v=B4HDGnJVe_o