vacuum chuck

[Haynie]

I read something that mentioned this so I did some reading. Is this as dangerous as it sounds, or am I off base?

 

[Ed McDonnell]

Not having read what you read, it's hard to answer your question. But vacuum chucks are widely used and are as safe as any other work holding method as long as you recognize their limits and use safe / good techniques.


Ed

 

[The Penguin]

can be dangerous - only should be used to reverse chuck and remove a tenon or detail bottom

from experience - leave the tailstock up to support the piece as much as possible...or that nice small natural edge bowl will fly across the room as you take the last piece of the tenon off....DAMHIKT

 

[walshjp17]

It is not dangerous, per se. With the right equipment properly used it is as safe as any other method. Most of the famous production bowl turners use a vacuum chuck to reverse chuck and clean up the bottom of their bowls.

The new Powermatic lathe (4224) comes with a vacuum chuck preinstalled. In fact it has everything you would ever need preinstalled -- it better for that price

 

[skiprat]

I've never used a vacuum chuck, but always wondered if they have a vacuumed chamber in line with the vac pump,?
If you lose power while turning, will the vac hold until the lathe stops spinning?

 

[Ed McDonnell]

I've never used a vacuum chuck, but always wondered if they have a vacuumed chamber in line with the vac pump,?
If you lose power while turning, will the vac hold until the lathe stops spinning?

I've not seen a vacuum chamber / reservoir used in a lathe setup. How long it will hold after power loss will depend on seals and wood porosity. Porous wood with lousy seals will lose vacuum pretty quick. But, in any case, the lathe should spin down pretty quick because you probably don't want to be turning uber heavy pieces at hypersonic speeds when using a vacuum chuck.

If power loss were a regular situation with no backup generator, you could consider one of the venturi systems that run off compressed air. Depending on your compressors capacity and when exactly the power went out (in the compressors fill cycle) you should have plenty of time to deal with the power failure.


Ed

 

[skiprat]

Thanks Ed, great answer!
That is the very first good use of a venturi system that I've ever heard of too!!

 

[keithkarl2007]

I've never used a vacuum chuck, but always wondered if they have a vacuumed chamber in line with the vac pump,?
If you lose power while turning, will the vac hold until the lathe stops spinning?

With a non-return valve fitted it could continue holding the piece for up to 25 minutes.

 

[Haynie]

I've never used a vacuum chuck, but always wondered if they have a vacuumed chamber in line with the vac pump,?
If you lose power while turning, will the vac hold until the lathe stops spinning?

This is what I thought about. Where we used to live, if someone sneezed two counties over we would lose power. All I could envision was the wood proving newton's law and flying straight at the turner.

 

[CharlesJohnson]

I have seen drawings in instruction that include a tank for this. I see no reason not to. Dose any one else see a problem.If not, I intend to use it when I get to set up a vacuum system. Thanks.

 

[Rodnall]

Some of the turners in our club were talking and one of them said they actually broke the bottom of their bowl from too much vacuum.

 

[lorbay]

When I shut the valve off when vacuum chucking I always hang onto the bowl and I know for sure that the lathe would have stopped before the vacuum was lost in a power outage. I am never turning that fast when vacuum chucking anyway. I have had 24" bowls on my vacuum chucks.

Lin.

 

[lorbay]

Some of the turners in our club were talking and one of them said they actually broke the bottom of their bowl from too much vacuum.

Been there done that.

Lin.

 

[AlanZ]

It is a simple matter to put a small UPS (uninterruptible power supply) to power the vacuum pump and an LED light. If power goes out, it is good not to be left in the dark... Mine is a basement shop, and I am usually there at night. The ups just needs to power the pump for a few seconds while the lathe spins down and you safely remove the work from the vacuum chuck.

 

[lorbay]

It is a simple matter to put a small UPS (uninterruptible power supply) to power the vacuum pump and an LED light. If power goes out, it is good not to be left in the dark... Mine is a basement shop, and I am usually there at night. The ups just needs to power the pump for a few seconds while the lathe spins down and you safely remove the work from the vacuum chuck.

Not if your pump is 220 volt.
Lin

 

[AlanZ]

APC and other companies make 220 volt ups units.