not sure of the exact measurement, but you can see the hole and hose dropping out of it here: czcams.com/video/VGGKKosgwpQ/video.html something between 1.5 and 2 inches I'd say. The shop vac I'm using is a beast with triple motors, so I can boost the vacuum when I have some leaky work pieces.
@@n0f8r Oh wow, I totally missed the hose going there, I thought it was plumbed further. That's very impressive! Thank you. Have a 4x4 on order and this bodes well for my plans.
hmm - vacuum holding is limited by atmospheric pressure, the most hold down force you can get is 15psi. So the absolute pressure rating of your pump is not that relevant, what you really want in the suction on a vacuum table is high Cubic Feet / Minute, that lets gives you some flexibility to have some leakage and still hold your parts down.
@@blancatrujillohigueras9865 it depends :) on your table size and how leaky it is, and how much surface area your parts have (larger surface area equals much more hold-down force) For my table and my parts I'm using a triple motor shop vac. It has 3 1000w vacuum motors with individual switches - and I find that sometimes I only need 1 motor, other times I need 2. It's very similar to this thing www.bradfords.co.uk/hyundai-3000w-triple-motor-3in1-wet-dry-electric-hepa-filtration-vacuum-cleaner-hyvi10030?gclid=Cj0KCQjw756lBhDMARIsAEI0Agl5n18I9LJmTm5A2V67tZaPBT55nznLheeoyUiMwi7uO_q54xAVHXYaAikvEALw_wcB
Thanks for making this video, it's a great vac fixturing system and this video is very well done. I did have one question, you mention early on how version one of the fixture had the air grooves and holes situated too close to the work edges. Could you expand upon that slightly? I've been experimenting with production vacuum fixtures and I am constantly looking to learn more about them.
The first fixture allowed too much air flow under the edges of the work pieces and through the cross-hatched air-flow channels - which also had too many through-holes in them. I was trying to increase suction by cutting those air channels and holes, but I actually reduced suction - a lot. Vacuum holding is all about surface area exposed to suction - but the surface area is no use if there's no suction :P So the solution was to remove most of the cross-hatch channeling and holes on the big rectangular slots, and provide sealing around the edges in the second-side-machining slots.
Thanks for sharing. This opened my mind to some possibilities I didn't realize before.
This video is totally great, thanks!
Very nice! What size plumbing are you using below the table ?
not sure of the exact measurement, but you can see the hole and hose dropping out of it here: czcams.com/video/VGGKKosgwpQ/video.html something between 1.5 and 2 inches I'd say. The shop vac I'm using is a beast with triple motors, so I can boost the vacuum when I have some leaky work pieces.
@@n0f8r Oh wow, I totally missed the hose going there, I thought it was plumbed further. That's very impressive! Thank you. Have a 4x4 on order and this bodes well for my plans.
the vacuum pump I'm looking at is 3553.42 psi ... that should work!
hmm - vacuum holding is limited by atmospheric pressure, the most hold down force you can get is 15psi. So the absolute pressure rating of your pump is not that relevant, what you really want in the suction on a vacuum table is high Cubic Feet / Minute, that lets gives you some flexibility to have some leakage and still hold your parts down.
@@n0f8r So, how many CFM do i need? thanks
@@blancatrujillohigueras9865 it depends :) on your table size and how leaky it is, and how much surface area your parts have (larger surface area equals much more hold-down force) For my table and my parts I'm using a triple motor shop vac. It has 3 1000w vacuum motors with individual switches - and I find that sometimes I only need 1 motor, other times I need 2. It's very similar to this thing www.bradfords.co.uk/hyundai-3000w-triple-motor-3in1-wet-dry-electric-hepa-filtration-vacuum-cleaner-hyvi10030?gclid=Cj0KCQjw756lBhDMARIsAEI0Agl5n18I9LJmTm5A2V67tZaPBT55nznLheeoyUiMwi7uO_q54xAVHXYaAikvEALw_wcB
Thanks for making this video, it's a great vac fixturing system and this video is very well done.
I did have one question, you mention early on how version one of the fixture had the air grooves and holes situated too close to the work edges.
Could you expand upon that slightly? I've been experimenting with production vacuum fixtures and I am constantly looking to learn more about them.
The first fixture allowed too much air flow under the edges of the work pieces and through the cross-hatched air-flow channels - which also had too many through-holes in them. I was trying to increase suction by cutting those air channels and holes, but I actually reduced suction - a lot.
Vacuum holding is all about surface area exposed to suction - but the surface area is no use if there's no suction :P
So the solution was to remove most of the cross-hatch channeling and holes on the big rectangular slots, and provide sealing around the edges in the second-side-machining slots.
I am surprised you only had 1 comment, nice presentation and it made me aware of wet dry shop vacs compressor operation.
What are you making?
thanks :) making these: czcams.com/video/jL4QAd45ZwA/video.html