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Thread: Holding the Workpiece

  1. #1
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    Holding the Workpiece

    What's everyone's preferred way to hold the work securely on the spoil board? I see different ways of doing it in videos. I am looking for a simple but effective method or methods. I realize small parts have different challenges than large ones.

  2. #2
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    SO...many choices.

    I don't have vacuum so I use a combination of screws and/or clamps to do work holding. Sometimes, I'll be creative and make a quick "clamp" from a piece of hardboard and a screw for something that has dimensions that are difficult to accommodate with clamps in the tee tracks and screws within the workpieces are too close for comfort. One thing I've also learned to do, especially when using clamps, is to screw some wood scraps up against the edges of a workpiece to stop any lateral movement in its tracks should one or more clamps fail to be tight enough to both hold down and keep things from moving sideways. "Stuff happens"...

    For one client, I have a fixture that gets screwed down to my spoilboard which has integral clamps and makes it easy to accurately flip the workpiece for two sided cutting. (chair seats)
    --

    The most expensive tool is the one you buy "cheaply" and often...

  3. #3
    I'm kind of like Jim - screws mostly, homemade clamps, and a handful of fixtures for the light production items.

    David
    David

    Nothing to do with woodworking at all, just our music at church (I'm the guy with the Koa Takamine)

  4. #4
    I use screws almost exclusively. If you are worried about the bit hitting one then use a brass screw but I try to give myself plenty of room. If I am going to make a small prodution run then I'll screw boards down that I can use as a jig and then it's just open one side, slide the new piece in and 2 screws and go. I just covered my t-tracks with MDF so don't have access to them anyway. I really haven't found that I really needed to use them with clamps with things that I make.

    I personally like the SPAX screws because of the bit. I never strip the heads out so I just keep reusing the same screws over and over. I keep a drill with a bit to predrill holes and a driver with the Spax bit in it to screw the workpiece down, next to the machine at all times.

  5. #5
    I use a lot of double sided tape. I also use tabs (cutting a small part out of a bigger part). I use screws from behind so they don't show on a finished surface. I've used glue, glue and paper joints, etc. Lots of variables to consider. Today, for example, I just needed to engrave a board for locating electronics. Not much force for engraving, so I just double sticky taped it down. Sometimes, I use an oversized blank to cut the piece out of and screw the blank down and make sure there is double sticky where the part is. Lots of good tricks out there. Sometimes, you just have to try stuff too. Also, I sometimes cut a few extras in case some get sucked up the vac hose!

    Tony

  6. #6
    Aluminum T-track has been a game changer for me-- I have two rails running parallel to each other across my spoilboard. I can use the track to secure clamps (without running more screws or drilling more holes in my spoilboard) as well as just bolt the piece down. That T-track will keep nuts from turning (though they can still slide left/right when loose), so I can drill a few holes in my work piece that align with the track (and don't align with anywhere I am cutting) and just bolt the sucker down. Now and then I still just use clamps, but I will often bolt down a stop of some sort in the tracks to keep the piece from shifting while machining.

    Basically, I'm sometimes a bit lazy and the T-track means I can expend minimal effort while still making sure my work piece is rock solid instead of going "eh, 3 clamps should do it".
    Licensed Professional Engineer,
    Unlicensed Semi Professional Tinkerer

  7. #7
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    I will add that I sometimes use the painter's tape and super glue method for holding really thin material, such as thin plastic used for a guitar pick guard and some of the thin plastic parts I've cut for customers
    --

    The most expensive tool is the one you buy "cheaply" and often...

  8. #8
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    I have a homemade vacuum table which gets the most use, but the vacuum level is limited to about 7 in.Hg. Sometimes I use purpose-made vacuum pods powered by a Gast vacuum pump and screwed to the spoil board Dowel pins aid in locating jigs like this on the table. For small, porous or otherwise difficult parts I use screws, screwed-down wooden clamping bars or blue tape and ca glue depending. I have tried various types of double stick tape with various levels of frustration. One of these days I will install the t-track sitting in the corner.

  9. #9
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    I use mostly vac but sometimes double sided tape or screws. I tried a Raptor nail gun that works great and if you hit one of the plastic nails it doesn't ruin a high $ bit

  10. #10
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    track it's covered over by the primary spoil board that's Thanks for the replies. Sounds like screws and improvised clamps are two of the most popular method. Even though my machine has T-Tracks they are covered over by the secondary spoil board that's added on top of the original. I surfaced the secondary and at this time have just ran screws through the work piece. However it's still mostly just a practice piece so I'm not concerned at this point. As I become more capable (think snail) I will likely want to not do any damage to the work piece. So I thought I would inquire as to what everyone's preference's were.

  11. #11
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    I have a straight edge on the left side that has been ‘squared’ with an endmill after it has been attached to the spoil board.

    Then I have a plate with a slot, that extends farther than the distance between the 2 cross “T” tracks. It is held in place with 2 “T” bolts and pushed up against my wedges, (2“ board cut from corner to opposite corner) tightened down, and then drive the wedges tight. If I need end support against moving, I just add a couple of stop blocks (with “T” bolt) into the long “T” track that runs the length of the table.

    Easy to make and hold a lot of things. You need to make the slot in the plate long as you can, which allows the plate to be clamped on an angle if need be.


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  12. #12
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    Are pallets a thing on woodworking cnc machines? Basically just a giant aluminum plate with a ton holes for pins. They’re threaded as well so clamps can be bolted in.
    Bumbling forward into the unknown.

  13. #13
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    Small fixture plate on a cnc router.

    small fixture plate on small cnc router.jpg

  14. #14
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    Quote Originally Posted by Brian Holcombe View Post
    Are pallets a thing on woodworking cnc machines? Basically just a giant aluminum plate with a ton holes for pins. They’re threaded as well so clamps can be bolted in.
    Many folks use that concept, albeit implemented differently. It's not unusual for someone to have a grid of threaded inserts in a CNC cable that can be used for work holding purposes. The surface is usually made of something like MDF because you feel a heck of a lot less unhappy if you hit it with a cutter than you would with an aluminum surface. Nylon bolts add a safety measure there, too, although metal fasteners also get used. While some folks do this on larger machines, it's more typical on smaller, desktop machines from what I've seen. There is nice value on a regular grid of embedded fasteners for work holding AND alignment...not unlike the value of the grid on a Festool MFT.

    An alternative on some machines is an actual aluminum bed made of strips that can not only hold an MDF spoilboard, but are spaced such that you can slide a nut/bolt anywhere along the length of the slot. And as you know from my machine, I have some embedded channels for holding clamps using bolts and nuts.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  15. #15
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    Quote Originally Posted by David Buchhauser View Post
    Small fixture plate on a cnc router.

    small fixture plate on small cnc router.jpg
    Awesome, that is exactly what I was thinking.
    Bumbling forward into the unknown.

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