[Baudros]

I'm looking to build a CNC wood router. Iwas wondering if there were any plans for building a vacuum holddown table for clamping workpieces. If not, how do you all clamp your material while routing? Sorry if I sound like a total newbie, I'm just not visualizing how to hold the material in some of these designs without a vacuum table.

[bp092]

Screws, carpet tape, leave tabs. I think there have been a few threads on the topic about a diy one made. I believe GER is making one or has right now for his machine. Some people were making them based on plans from a site that shows DIY ones for veneer presses. I suppose they aren't that hard to make if you have a decent compressor you could use and a way to integrate it with your table.

[ger21]

http://www.cnczone.com/forums/showthread.php?p=275063

http://www.cnczone.com/forums/showthread.php?t=17535

[Greolt]

Baudros

I have a thread going on my efforts making a small vacuum hold down device.

http://www.cnczone.com/forums/showthread.php?t=34537

As you will see in the thread it is not difficult nor is it original in any way.

If you want to want to hold large sheets or very small objects that is more challenging.

The big comercial machines typicaly hold large sheets and need to cut out shapes or panels and cut through into a spoil board.

They have very large capacity vacuum pumps.

But if your requirements are simple like mine you may want to follow along as I attempt to convert a cheap air compressor into a vacuum steup.

Just waiting on international mail to bring me a switch, guage etc. right now.

Greg

[Madclicker]

I use 2 methods of vacuum holddown. For larger cabinet panels, i use a LDF bleeder/spoil board and 2 shop vacs in series. For smaller, less porous pieces I use a high quality, low volume pump with good gasketing.

Once you use vacuum holddown, you'll wonder why you did it any other way.

[robertbrenton]

I looked at a few options for a vacuum table. In the end I got lazy and purchased a "BIG-MACH KIT" from the link below to get me going. The main thing I was after were the ball valves which take away the hassle of covering unused portions of your table.

https://eagleamerica.com/product.asp_Q_pn_E_500-0100
http://www.m-powertools.com/products...h/big-mach.htm
Interestingly enough the price of this kit at eagleamerica is less than half the price of the exact same kit in the UK. Either eagleamerica forgot to convert the price to US dollars or people in the UK are being ripped off.

If I had to purchase again I'd just buy the ball valves and source the gasket material from a local rubber place. The cheapest ball valve I could find here in Australia was $8 each.

Main change I'm making to the plans is that rather than using the provided gasket material between the bottom board and the top board to create the vacuum channels I'm going to router channels into the base board and glue the top board on. Main reason is that I want to use a thinner top sheet so I don't loose valuable Z axis stroke. Also I'm using a laboratory vacuum pump (22cubic metre hour / 30" vacuum) and only need small channels to distribute the vacuum (large voids in the table being pulled at 30" of mercury may also deflect the top sheet).

Although not specified in the instructions I'll paint the MDF surfaces to reduce leakages & increase durability from spills etc.

[nambass]

I am in the process to build myself a vacuum table. the CNC is a 6"x 8". The concept I line is the one using the slots where I can change the vacuum area by changing the rubber bands. it is versatile and seems to work great.

I do have a few questions on this...

a) What will be the best pumps to use? and howmany?
b) what taps will be best
c) what kind of board (particle or MDF) board will be the best for the spoilboard, and by removing on both sides 1/16" will that provide enough suction? (the spoilboard is 12mm)
d) anyone have a diagram of how to do this.