Peter Grey wrote:

Hi all,

I want to build a vacuum chuck. I'd like to build one that can hold a piece
up to 10" square with the ability to block off some holes and use it for
smaller pieces. I'm trying to figure out what pump is appropriate to try to
find used. In looking at what's available from MSC and others, it appears as
though a pump that pulls at least 26" is about right. How important is the
CFM rating in this application? I'm assuming that a pump's max CFM will
influence how quickly the chuck builds vacuum, and depending on how much
leakage gets past the item I'm machining and its contact with the chuck, how
easily it'll maintain its hold. Any suggestions about minimum specs I
should be considering.

Thoughts and suggestions welcome.

Peter




We have used the really inexpensive venturi type vacuum pumps when the
leakage was kept to
a minimum. These pumps work on shop compressed air and have no moving
parts.
CFM rating will depend on how much leakage there is in the setup. If
coolant is used in machining
a catch tank in the line will be necessary to keep it from getting to
the pump.