construction of a vac table and tests following

[stan kern]

using Sean Martin's ideas on a vac table ,I re-designed it a bit and built one 28x48 in and I am showing the construction and the testing that follows
It works fine



http://youtu.be/ZlavIPiicCM

[Mike Heidrick]

Great job Stan!! - Since you are mostly not cutting through - ever consider a venturi system with a vac holding tank so the machine does not stay running? Also what happens when a bit does cut through on your setup? I am using a regenerative blower vac pump and actually suck through LDF so I just cut into that. Do you have enough pressure to suck through some 1/8" or 1/4" ldf or mdf? The big Becker pumps suck through 3/4" -1 1/2" of MDF!!

[stan kern]

I also have a vac pump but with this large work area a pump cannot handle the volume,now if it had seals
it would probably be ok
Secondly this is mainly used for the drag knife
Here is what I use the pump with
http://youtu.be/5Sqm1MnQe7Y

http://youtu.be/Yz0SNddVJKU

http://youtu.be/LvuIyXXKgPY

[Mike Heidrick]

Thank you again.

[Keith Outten]

Stan,

Is there an advantage to a large vacuum chamber as opposed to a series of small grooves? The pucks do really well with small cavities I wonder why large tables require more space.
.

[stan kern]

It turns out the vac pump cannot pull on a large number of holes at all, you need some sort of sealing between the pump suction and the material.The vac pump can run a bunch of pucks , a vac cleaner cannot pull on a small hose or hole.
So vac cleaner connected to a table full of hoes is good for vinyl .paper, veneer,cardboard etc ---but when it comes to a board the vac pump and a puck is what to use

[Mike Heidrick]

but when it comes to a board the vac pump and a puck is what to use

That does not allow for a cut through though correct?

[stan kern]

Yes you can cut through just use pucks small than the cut or I use a porous 1/8 pegboard and cut 1/16 into that
you don not want to cut the seal
http://youtu.be/rSQvrg2TKzE


http://youtu.be/LvuIyXXKgPY
Thevac cleaner seems to e ok for large areas

[Roy Harding]

I have a small Shopbot Desktop (cutting area 24" X 18"). I built a vacuum table using a shop-vac. The table top is MDF, pierced by 1/4" holes in a specific pattern. I use pieces of hardboard to cover the holes not covered by whatever I'm cutting. I works REALLY well - but I still use clamps on the edges, as lateral forces generated by some cuts occasionally cause the workpiece to slide slightly.

I will eventually replace the shop-vac with a small DIY vacuum pump - but just because I know that I'll eventually burn out the motor on the shop-vac (not to mention the noise).

[stan kern]

that's correct ,a vac will finally stop working ,it cannot seem to take running long periods of time blocked but it does do job on table surface with many holes

[Roy Harding]

that's correct ,a vac will finally stop working ,it cannot seem to take running long periods of time blocked but it does do job on table surface with many holes

I believe that's because the vacuum motor is cooled by the intake air - when there's no airflow, there's no cooling of the motor.

[Mike Heidrick]

I use a relief valve and a solberg filter on my regenerative blower setup. Those would be nice to incorporate into these vac setups too.

[Jerome Stanek]

I use a Fein vac they are nice and quiet and you can run them for hours for hold down