Results 1 to 10 of 10

Thread: More progress!

  1. #1
    Join Date
    Mar 2007
    Location
    Escondido, CA
    Posts
    5,167

    More progress!

    I love simple, eloquent solutions.

    So I was designing a vacuum hold down table for the CNC. Actually there will be two of them. I am working on the vertical one. I got some vacuum ball valves from MP Power. Then came the plumbing. The table is HDPE plastic. Thought about routing a depression between vacuum pods and screwing on a boss. My experience with keeping bosses from leaking is not stellar. So I found a nylon tee with hose barbs. But the ball valve didn't fit. Needed a bushing. Enter a short length of 1/2" clear tubing. Press fit. Pretty snug. Should not leak. Eloquent!

    I love it when a plan comes together, even on the fly.

    Now to rout a counter bore on the back to make the vacuum ball valve flush with the front surface. Then drill and tap with 1/2" pipe tap. Cut some foam rubber washers out on the laser and screw in the fittings. Add hose lengths and done. Then on to the off/on ball valve for each zone and into a manifold and on to the vacuum pump.

    Click image for larger version. 

Name:	Vacuum tee.jpg 
Views:	25 
Size:	33.2 KB 
ID:	96026

    More pictures soon.
    ++++++

    Some say the land of milk and honey; others say the land of fruits and nuts. All together my sort of heaven.

    Power is not taken. It is given. Who have you given yours to? Hmmmm?

    Carol Reed

  2. #2
    Join Date
    Jun 2007
    Location
    Oceanside, So. Calif. 5 mi. to the ocean
    Posts
    4,944
    Jeepers Carol. With all of that work you might just as well have a garden; they can take up space and time also.

    Enjoy!
    JimB
    First of all you have to be smarter than the machine.
    VOTING MEMBER

  3. #3
    Join Date
    May 2007
    Location
    Kansas City, Missouri
    Posts
    13,427
    Interesting! So if I'm following, the balls get pushed down by the object to be held and only those ports are open, correct?
    Darren

    To a small child, the perfect granddad is unafraid of big dogs and fierce storms but absolutely terrified of the word “boo.” – Robert Brault

  4. #4
    Join Date
    Mar 2007
    Location
    Escondido, CA
    Posts
    5,167
    Quote Originally Posted by Darren Wright View Post
    Interesting! So if I'm following, the balls get pushed down by the object to be held and only those ports are open, correct?
    You got it in one, Darren.
    ++++++

    Some say the land of milk and honey; others say the land of fruits and nuts. All together my sort of heaven.

    Power is not taken. It is given. Who have you given yours to? Hmmmm?

    Carol Reed

  5. #5
    Join Date
    May 2007
    Location
    Kansas City, Missouri
    Posts
    13,427
    Cool! Do you have a link to the product you can share?
    Darren

    To a small child, the perfect granddad is unafraid of big dogs and fierce storms but absolutely terrified of the word “boo.” – Robert Brault

  6. #6
    Join Date
    Mar 2007
    Location
    Escondido, CA
    Posts
    5,167
    Here ya go!

    http://www.m-powertools.com/products...all-valves.htm

    Click image for larger version. 

Name:	ball-valves.jpg 
Views:	8 
Size:	28.0 KB 
ID:	96047

    Also found on Joe's Woodworker's site for more money but some cool ideas.
    http://www.joewoodworker.com/veneeri...umclamping.htm

    Look near the bottom of the page under Podz.
    ++++++

    Some say the land of milk and honey; others say the land of fruits and nuts. All together my sort of heaven.

    Power is not taken. It is given. Who have you given yours to? Hmmmm?

    Carol Reed

  7. #7
    Join Date
    Jun 2008
    Location
    GTA Ontario Canada
    Posts
    12,243
    Cool solution saw those a while back on Joes site an wondered how good they were.
    cheers

  8. #8
    Join Date
    Mar 2007
    Location
    Escondido, CA
    Posts
    5,167
    Vacuum clamping works extremely well - if you follow the law of physics! Joe's PODZ are made of HDPE which is a spendy plastic, especially in 3/4" thickness. I had an almost full sheet left over from my router jig making days that I am using for the CNC. The point being, the material has to be impervious. Air moves through wood and wood products at various rates, meaning an air leak in the vacuum clamp. Not good. Good place to use plastic.

    FWIW, I created the syllabus and taught classes on vacuum clamping back in the days I was teaching woodworking. Long before Joe Woodworker! My students did try sealing wood like MDF with varied success. It has to be a really good seal! The tape that creates the vacuum space must be closed cell. I used to be able to buy closed cell door and window seal foam PSA tape. Lately I could not find packages labeled as such so I got a roll from Joe. The tubing has to be of sufficient wall thickness so as not to collapse. I also got that from Joe as his price was very fair and I had an order going.

    If you use the ball valves your substrate has to be be at least 3/4" thick to accommodate the length of the valve. If you made doubled sided pods, the surface you are sticking the pod on must also me impervious. This is much more problematic. And the material you are trying to hold must not leak air too bad. Closed cell wood works best. Red oak is the worst!

    There you are, the short course in vacuum clamping. Vacuum BAG clamping is another ball game not to be confused with pod clamping.

    There is more to know about applying vacuum and intentionally breaking vacuum and vacuum pumps in general. Holler if you really want to know.
    ++++++

    Some say the land of milk and honey; others say the land of fruits and nuts. All together my sort of heaven.

    Power is not taken. It is given. Who have you given yours to? Hmmmm?

    Carol Reed

  9. #9
    Join Date
    May 2007
    Location
    Kansas City, Missouri
    Posts
    13,427
    Excellent info Carol. Seeing those valves makes more sense now of what you did on the first post with the tubing and tee, that is an excellent solution.
    Darren

    To a small child, the perfect granddad is unafraid of big dogs and fierce storms but absolutely terrified of the word “boo.” – Robert Brault

  10. #10
    Join Date
    Feb 2008
    Location
    East Freeetown, Massachusetts
    Posts
    3,014
    SWEET

    I have yet to try vacumn clamping but I know it's the way to go. I like the ball valve idea.

Similar Threads

  1. Progress!
    By Carol Reed in forum New Systems and Builds
    Replies: 6
    Last Post: 05-28-2016, 03:19 PM
  2. Watchbox-in progress
    By allen levine in forum Flatwork Project Showcase
    Replies: 38
    Last Post: 12-16-2008, 03:03 AM
  3. Second Bowl in progress
    By Keith Palmer in forum Lathe Project Showcase
    Replies: 4
    Last Post: 09-27-2008, 03:17 AM
  4. Playhouse progress
    By Bill Lantry in forum General Woodworking Q&A
    Replies: 2
    Last Post: 08-31-2008, 10:16 PM
  5. Progress
    By Tyler Howell in forum Shop Tours
    Replies: 22
    Last Post: 03-19-2007, 10:26 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •