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Thread: Work holding for non-vacuum tables

  1. #1
    Join Date
    Feb 2017
    Location
    Normal ,IL
    Posts
    1

    Question Work holding for non-vacuum tables

    We recently set up our SB Buddy and it's dedicated cyclone dust collector. The Buddy will be used by undergraduate and Graduate students in our Fine Arts program.

    What we haven't done is decide on work holding for the various materials we will be cutting. We will have multiple departments with the School of Fine arts using the machine: Ceramics, Sculpture, Expanded Media, Graphic Design...etc. This means we will be cutting wood, acrylic, plaster, and foam. Everything BUT metal. Unfortunately, we do not have a vacuum table. To compound the matter we are not going to be using any metal fasteners as the faculty is concerned that students will cut them and break the tooling and/or hurt themselves. Not that a student has ever done something like that.

    The vinyl nails SB recommends seem a little flimsy for work holding; has anyone had success with them? My experience is with manual and CNC mills, so I want to have a Kurt vise and some T-Bolts....which obviously isn't going to happen.

    Festool's perforated table tops work great. I have one that was bought new when they were first released in NA. My thought was to replicate the design on an elevated spoil board to take advantage of the Z travel we have.

    Any out-of-the-box ideas for work holding that have worked for you?

  2. #2
    Join Date
    Jun 2013
    Location
    Pasadena, CA
    Posts
    871

    Default

    Not sure if you mean the Raptor nails when you write "vinyl nails" but if so they are not flimsy at all and hold down well, don't break the bits and can be sheared/sanded off. Unfortunately the required Omer nail guns are very expensive.
    I use these polymer nails rarely since I do have vacuum but once a while I have parts too small or complex for vacuum pods and then the Raptor nails come handy. At other time I use wood screws, aluminum clamps or whatever works. FWIW, 1/4" bits or bigger can survive a collision with aluminum clamps.
    Box Joint and Dovetail Software Here

  3. #3
    Join Date
    Mar 2016
    Posts
    25

    Default

    We have a vacuum table, but I find we were using 23ga pins out of convenience (odd sizes, etc) - if the bit hits a pin, not the end of the world, and they are easy to pull.

    However, I ran across this video that changed everything for me:

    https://www.youtube.com/watch?v=ub6PsY4cgwg

    To be clear, I have extensively used double sided masking tape a lot with some success, but some failure as well. And it's just too expensive. There is often no way to get really good "rub the adhesive into the part/table" contact on one side. You can beat the hell out of it with a mallet and hope you get good contact.

    This changes everything, and I'm holding down things (without clamps) that I never would have attempted (see photo attached). That entire block is all of 3.5"x5.75". With the method in the video, you can really work the tape into both the part and the table, then use a medium or thick CA glue to secure the two. The glue makes up for any unevenness in the union where the double sided masking tape failed. And it's way way cheaper even with double the run of tape and a line of glue.

    Once the part is done, it takes a rubber mallet to shear it from the table, but the tape just peels right off, no residue on the part or table. Or on larger parts, just use it in the corners, center, whatever.

    Marc

    IMG_2959 1.jpg

  4. #4
    Join Date
    Sep 2006
    Location
    cnc routing, portland or
    Posts
    3,447

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    I use transfer tape over the regular tape as iti s much wider though I wish It stuck better. usually I throw the parts in a vacuum bag to make sure they are stuck together.

  5. #5
    Join Date
    Jun 2004
    Location
    Springfield Mo
    Posts
    767

    Default pull-down

    I have a number of 17/64 holes that go through the table on 5 1/2 inch centers. For small signs I drill a few holes in the bottom of the work-piece at say 11 inches. Thread as desired.

    I use a proper length lag bolt to "pull the piece" down. As long as you stay above or beside the bolts it is fine. Entire upper surface is free to cut. Beginners can use a nylon threaded bolt ...
    The decimal point seems to be the most important on the z axis... x & y not so much....
    ShopBot... Where even the scraps and things you mess up and throw away are cool....

  6. #6
    Join Date
    Aug 2012
    Location
    Davenport Iowa
    Posts
    157

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    A friend told me about this and it works great! No more clamps,screws,naile or need of a vacuum. Take a look give it a try and let me know how it works for you


    https://www.youtube.com/watch?v=3uTsQ3dYRrk
    Life is like a project you continue to work on until it's finished.
    Never start a project you don't intend to finish!

  7. #7
    Join Date
    Jun 2013
    Location
    Pasadena, CA
    Posts
    871

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    I did experiment a bit with various adhesive methods, including the CA/masking tape idea. It did work well enough for larger parts but I can hold such parts much better and simpler with a vac pod.
    For smaller and intricate parts neither the double sided carpet tape not he masking tape held up well unless using really small bits like 1/16". The other thing that bothers me is that the bit often curls up snots of the tape adhesive when cutting through and that it is often a pain to remove adhesive residue from the surfaces (have not tried transfer tape, though).
    After all, I use a variety of methods, gave up on the adhesive tape and still don't have a real good solution for very small parts (say <1 square inch) other than tabs.
    Box Joint and Dovetail Software Here

  8. #8
    Join Date
    Apr 2013
    Location
    Kennebunkport, Maine
    Posts
    3,669

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    G.
    Had VERY good luck using the carpet tape shown(1.88" width essential)/ and the "No Residue" Duck tape on a surface like HDO(waxed) or lacquered/waxed wood.
    "Bonnie" buttons were .75"D, and the Bloodwood "Trees" were cut Monday and no residue even though that Bloodwood has been stuck down 11 months(AND STAYED stuck FLAT) and were cut out using a .5" (.25"R)pointed round over bit.
    The trick is to cut only into the no residue tape, and to make last pass less than .01".
    I don't know, but works great for me.
    scott
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    Scott Plaisted
    Desktop/spindle/VCP 8.5**
    Maine

  9. #9
    Join Date
    Jan 2004
    Location
    Norman, Ok
    Posts
    3,022

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    Roehm

    Thank you for posting.

    This topic is usually about vacuum systems which I don't use. I for one have been routing detailed large signs for years and don't rely on stickey stuff or a vacuum. Vac systems are excellent in many application but for those of us who route uneven, rough surfaces a physical hold downs work well. Also when carving letters we screw our substrate down using bridges for the lettering. Small delicate dingbats and decorative detail work is also done with bridges.

    When carving large 3D panels, which takes several hours and done overnight, sticky tapes or vacuums, we've found isn't the optimum way to go. Opening up the shop in the morning to find a panel has moved will start the day off wrong. Each of us has to find their best method. All of the above methods seem reasonable and fit the operators methods. I like screws and the Raptor plastic attachment method. But for the most part it's screws for me.

    Joe Crumley
    www.normansignco.com

  10. #10
    Join Date
    Dec 2008
    Location
    Diamond Lake, WA
    Posts
    1,439

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    I use a 1" thick piece of MDO with slots milled for T-tracks (Rockler). Then I make the "clamps" from OAK or HICKORY for strength.

    I'd like to attach pictures but no matter what I do this BBS won't let me upload the pictures. Used to be easy...
    Don
    Diamond Lake Custom Woodworks, LLC
    www.dlwoodworks.com
    ***********************************
    Life is not a journey to the grave with the intention of arriving safely in one pretty and well preserved piece; But to skid in broadside, thoroughly used up, worn out, bank accounts empty, credit cards maxed out, defiantly shouting "Geronimo"!

    If you make something idiot proof, all they do is create a better idiot.

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