Vacuum table revisit Part2 - CNCnutz Episode 244
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- เผยแพร่เมื่อ 7 ก.พ. 2025
- www.cncnutz.co...
Welcome back to part 2 of my Vacuum Table build.
In this Video I investigate 2 tabletop designs for their holding ability, and talk about the vacuum I purchased for this project and if I get time to clean up my workshop.
I also I have links to the cad files for those who want them.
In the last video I built the table base from a piece on Melamine coated MDF and sealed the edges of it to prevent air leaks. The one thing I learnt for sure was that MDF is a very porous material and when it comes to air you need to seal it. I sealed mine with several coats of acrylic paint though you could also apply edge banding to the MDF as well. In that case you might want to keep the outside shape square for easier banding.
I also made a top that was plain MDF on which I skimmed 1mm of material off the entire back and 1mm off the vacuum area on the front. This is to open up the MDF by removing the compressed surface to get access to the less dense material for greater air flow. I made the tabletop as easy to make as possible as it is the part that will be damaged while in use and a new one can be made quickly once it has no more life left in it.
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I hope you enjoy.
You made my day Peter, I'm new at this vacuum table idea but now I learnd a lot.
Thank you Peter - I find your instructional videos to be one of the best on TH-cam. Appreciate you sharing the plans for the vacuum table and your time spent sharing your knowledge.
Thanks Theo
This is awesome. Two options I think would make it better. Either put the holes on the underside to clean it up and eliminate sawdust magnets or.. just use a thinner top bit. Can’t wait to dive into my build!
Thanks for the video. I have been thinking about this issue and now I can make a good Table based on your testing. I did download your files so thanks again.
Great informative video as always Peter. Hope you are doing well in these crazy times my friend. Take care.
Thanks Dave. Doing good here so far. Crazy times indeed. Keep the bread coming and look after yourself.
Cheers Peter
Hello Peter... I built your vacuum table over the weekend and found something interesting. I tried my contractor shop vac, and like you said it didn't supply enough suction to work adequately. I did find, however, that if I removed the filter I got significantly more suction
Great video as always Peter. Interesting info on the table
Thank you very much, you have earned Heaven for share all your experiences, receive a great salute from Monterrey MEXICO
If only it was that easy Luis
very good job, thanks for sharing
Excellent info, thanks for sharing this.
I built a similar table, for my onefinity. It does cover the whole 48x30" surface with 4 zones. Extensively researched the vacuum engine to use or the shop vac and concluded the same. Festool does have the highest vacuum force i could find with an appropriate cfm to match. Also, all their vacuum goes up to 3.5psi so using the smallest one is fine. For actual vacuum engine, the ones that are stronger and cheaper all require 220V which isn't possible for me.
Hi Peter this reminds me of a machine I ran. If you make the top plate a spoil board you can drill 1/4" (7mm) holes under the part you are machining. it pulls down great. it would be nice if you could install a gauge to see how much vacuum you are pulling. The Komo machines we had pulled 30 inches of vacuum. I'm sure you can see images of the tables if you search on the internet.
Thanks. Will have a look.
thank you peter
Thanks Marouane
Plastic garbage bag rather than the semi-closed cell foam with holes poked. Cover then entire permeable surface of the spoilboard, place the workpiece, cut around it with a razor knife, then remove the plastic under the workpiece. This will eliminate bleed. I think you'll find there's little or nothing to be gained by drilling holes. There are reasonably priced vacuum pumps that you can use in place of a vacuum cleaner (which is not designed to be run while flow is occluded).
With a proper vacuum pump able to pull about 26” of mercury, you don’t need holes. Seal the ends, surface the top and you’ll be able to hold snug to the mdf
Excellent thought and process all the way through and building on every previous experience - Thank you very much.
Just building on your closing last ideas -
Foam sheet comes in 2 varieties. It looked (can't be sure of course) like you were using common open cell foam and that will definitely not work. It will actually introduce pathways from the side to between board and stock. However, perhaps you could try closed cell foam (the stuff used in double skin boat building) which while not allowing unexpected pathways could actually compress across the board and provide suction under the stock with punctures under the area below the stock.
Putting foam aside all together, how about a plastic trash bag (- cheaper and thinner the better) punctured in strategic array.
My final no cost solution - raid the kitchen for Saran wrap? Used similar to your paper and punctured strategically.
Still, the episodes were brilliant. Thanks again.
You really have my interested in the VAC table. New to the CNC world anyway you indicated that you had a Vcarve file. I downloaded the zip file but can't find the Vcarve file. Jon
I still think you should try what I suggested in the last video, and that is to pocket from the bottom so the top surface is still flat.
If he pockets from the bottom, how many times can he resurface the top before the holes are completely exposed?
nah, you want to maximize the surface area of vacuum that interfacing with the workpiece.
All the industrial machines I've used had regenerative blowers which move allot more air.
Thanks Stephen, I will will have to have a look.
Cheers Peter
@@cncnutz i just finished modeling up a 150mm diameter version in Fusion360. I plan to print it out on my 3d printer to see if I can replicate a simple version using an old electric motor I had in the shop. Hopefully can generate enough vacuum with it to make my own vacuum table.
Sorry, hit the wrong key. Although I don't have a scale to actually measure it, it does seem promising for those of us with shopvacs. Thanks for all the inspiration you provide us.
Now that you have 'calibrated' the holding force in XY and Z, have you ever seen the work move under cutting conditions, so that you could estimate the lateral and vertical forces applied under use?
Awesome
reversing the pockets on the bottom side would improve the pocket test. so there is a nice flat surface on the top
nah, you want to maximize the surface area of vacuum that interfacing with the workpiece.
"Inconceivable!"
AWESOME!!
Good day Peter. I’m just getting started in cnc use and am curious about how well your vacuum table works with fairly small pieces of hardwood in actual cnc routing. My concern is about smaller pieces coming loose if tabs are not used.
I'm thinking of doing something similar - the tabs and 'sprue' used for smaller pieces is forcing me to use larger blanks than I should have to. I was thinking of either making 'jigs' that have specific suction holes or using larger 'cover' type boards to cover over the table area I'm not using. I would think it might put stress on your vaccuum though...
Would not it be better to use plastic for the first piece with the groves and vacuum holes as it would not allow air to be sucked thru it ?Also it would not warp when exposed to moisture in the shop ?Also then using a thinner mdf so it doesn't have to pull vacuum thru as much material .Then paint around the outside of the mdf to seal the contact points of the bottom piece and top-waste board
Hi Peter, thanx for all your info. I was wondering. The Foam ring you apply around the board, is that necessary . If one would have the same size board underneath and on top, and seal it with Ductape or something, would that do the trick as well you think ??
I think you need to find a balance between how much your vacuum can pull and how thin you need to go on the MDF to allow that much flow. When your vacuum produced virtually no increase in performance from half to full power, it seemed to me that your table was the limiting factor there; it was blocking most of the flow at rates over 50%. You can probably use the same thickness but balance it with holes drilled partway though as you did there. In all 'factory' type tables I've seen, the shape of the holes is part of the puzzle as well.
The newspaper is interesting, but I think the result was slightly inflated due to the paper extending past the test piece and covering more area than without it. Possibly cover the whole area beyond the test piece with an impermeable barrier and run the tests again?
Another interesting test (that I have no idea how to conduct right now) is to see how much vertical force a cutter produces.
Your shop vac should work fine for a long time but you need to allow enough flow over the motor to cool it. Add a fan or some sort of cutout valve to control that airflow to optimize it? Maybe a cutout valve might help your full-speed performance as well. You could open the cutout valve a smidge to allow some air over the motor while maintaining suction performance at the table.
Another very good video with great info and testing, I believe you posted on your site under the materials the following 940 x 60 x19mm I'm guessing it should be 600?I don't have my laptop with me right now but I'm looking forward to doing this project. Have a great day.
Thanks Donald, I will fix the typo. It will fit better if you use 600mm 😁
Cheers Peter
@@cncnutz I'm new to all of this and metric is not my go to measurements. Have a great day.
If you would like help, I can give you some help with the vacuum hold down. I worked with a Thermwood model 40 With a vacuum table for 10 years. Also I was at a elevation over 1 mile in Boulder, CO. Lets just say you learn a few tricks along the way.
Bobby Little, My elevation is 3500 feet, performance of my vacuum table is not optimal. I would be very interested in any tips you would like to share. Thx, Mike. Cncvisions@frontier.com
Wondering if you received my email?
I don't seem to have it Bobby. Can you resend.
Cheers Peter
Could you send your email address and I'll try again with my Ymail.
@@bobbylittle6996 Please use the contact form on my website: www.cncnutz.com
You will find it at the bottom of the page on the left hand side of the screen.
cheers
Peter
How will this vacuum table work for veneer milling?
1/2" honey-cone cardboard works amazingly
well the smoke tset is flawed im afraid, since it also did not draw into the mdf on the top. while the top certainly sucks the material onto the thing
Why not use side blower which are actually made for vacuum table, side blower will not overhead as they haver separate motor cooling. Do not use vacuum pump unless you have fully sealed table. BTW: Very nice and detailed presentation
Thanks Zulfqar
Since the top layer of your vacuum table now becomes your spoilboard, do you find the cut marks having a big impact? I use your technique of zeroing to the base to minimize the cut marks, but they're still there.
I wonder what would happen if you used a thin MDF sheet (like 3mm) on top as the spoilboard...
This is where adding newspaper or foam between the board can help as it provides the extra height to protect the actual vacuum table top. I need to do more testing but the other option is to not cut all the way through. Doing this keeps maximum vacuum.
Cheers Peter
Great video
Have you install a vacuum gage on your system to see how much your pump is pulling?
I don't have one to try and it will be at least a month for lock down to end her in New Zealand.
Cheers Peter
@@cncnutz Make yourself a water manometer, vacuums pull about 25 - 29 inches.
how do ya get the free files for the vacuum hold down table
Follow the link in the description box below the video
Have you tried using 6mm or 12mm MDF for your top sheet.... possibly could give a good middle of the road between pockets and flat sheet. BTW thankyou for your uploads they are always informative and clear looking forward to seeing more.
I haven't Dale but it is good thought. If I can find some thinner board I will give it try.
Cheers Peter
@@cncnutz why not mill it to the thickness?
Hi,
Firstly great video, thank you
On the original video’s you used the Festool - I think you said it broke hence changing to the new model.
I will be making something similar, and will use the Festool.
Question - was it the vacuum table that killed the Festool ?
Cheers
Andy
don't find a way to email. The contact me on the website is not configured correctly. Any way I really appreciate the videos and I'm going ask a stupid question. I work a lot with rough western US cedar. Neither side is planed.
without planing will your table be able to hold it down the board. I usually work with 8-12 wide and 2 in thick
thank you andy
Vacuum tables require flat planned surfaces for the best holding. A small leak and everything let's go. I think for rough sawn not flat material I would try thick foam with suitably placed holes to create holding points and see if that worked. I would be holding it so I could machine the other side flat and then flip it over for better holding. There is a contact page on my website for contact purposes.
Cheers Peter
any reason you are measuring in pounds instead of kg?
I learnt air pressure as 14.7 pound per square inch when I took up diving 25 years ago and that is how I think of it. It's the same way I use Ozin for stepper motors. I don't use pounds for anything else. Strange how the mind works.
Cheers Peter
Because the Imperial system is vastly superior to the metric system, and it's delightful to see metric snobs cry over something so bloody trivial. But hey, I guess identity politics is destined to infect everything on the planet, so why not have the infection spread to one's choice of measurement.
I doubt very much that my shopvac could survive the length time it takes to run most jobs I do with essentially no airflow through the vac. Any thoughts on how to mitigate this Peter?
Use a vacuum with a dedicated cooling circuit
Thank you Peter very much for this video. Valuable info and I'll look at it again to glean more gems.
My expectation is the duty cycle on the vacuum is more likely a lot lower than 50%. (As an aside, did you see Jerry Fielding's recent video on shop vacuums and their power ratings? th-cam.com/video/oM4SMQGMFz8/w-d-xo.html). You might find a more efficient second hand pump ex a dairy farm. A friend just suggested to me to add a second vacuum pump to the manifold as the two together will provide more suck.
It was interesting to see the significant improvement in holding capacity with the thin packing foam and I recall the improvement newspaper had made in a previous vid of yours a couple of years ago.
Cheers, David
Thanks David. Interesting idea for sure. Don't know if i could handle all the mooing. 😉
I'm hoping to go further with the foam but I can't get any at the moment until New Zealand reopens. your right about the vacuum. If my vacuum usage is anything to go by 0% would be closer to the mark.
Cheers Peter