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Thread: Shaper hold down clamps

  1. #1
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    Shaper hold down clamps

    I'm looking for a upgrade to my sliding table shaper hold downs. I will be cutting extended tenons and don't trust my current set up. I see some pneumatic hold downs on Amazon. Has anyone ever tried those or if there a better option? I attached a picture of my current set up and the Amazon clamps.
    20220428_175512.jpgScreenshot_20220428-182631_Chrome.jpg

  2. #2
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    I like pneumatic cylinders personally. They are cheap, easy to configure, effective as clamps and versatile.

    20220425_204230.jpg

  3. #3
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    Airtight clamps seem to be the best, most expensive around. Popular with the Felder owners. You can find single action cylinders on the auction site and fabricate up a holder, but it becomes an involved process with air supply etc.

    Bimba cylinders seem the most common in the 174 size, but you could likely use the shorter 172 or 173. Bimba cylinders have an odd sized rod, so you will need an adapter for whatever foot you use. Luckily you have McMaster Carr for all the parts you would need.

    I am fabricating a set of clamps for my slider right now, including a thruster for lateral clamping to the fence extrusion. It gets spendy quickly if you use stainless and fancy hardware for the holders. I think I have > $800 invested in all the parts.

    Greg

  4. #4
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    Quote Originally Posted by Jared Sankovich View Post
    I like pneumatic cylinders personally. They are cheap, easy to configure, effective as clamps and versatile.

    20220425_204230.jpg
    How are these mounted? Do they have a flange on them?

  5. #5
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    Quote Originally Posted by Mitch schiffer View Post
    How are these mounted? Do they have a flange on them?
    They are nose mount cylinders. Though there are other configurations.

    20220428_205726.jpg
    20220428_205933.jpg
    20220428_205640.jpg

  6. #6
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    Quote Originally Posted by Jared Sankovich View Post
    They are nose mount cylinders. Though there are other configurations.
    Thanks. I ordered a couple similar cylinders off ebay that im hoping will work. Do you ever find the hose to be in the way?

  7. #7
    How much travel do you need. They make shorter air cylinders.

  8. #8
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    I'm thinking 2" then I can use the same set up for 3/4 stock up to 2 1/4 stock and still have 1/2" to get the thicker stock in place.

  9. #9
    thats sensible for up to 2 1/4" doors. Old guy said he did doors in 2 1/4 and 3 3/8 then the thick church stuff. I need to go to city hall sometime and see if his doors are still on there and if so what they are.

    Im not sure the travel on my shorter ones on two machines but will try and measure that tomorrow. I think it wont be enough. Air for them is simple with a toggle switch but past i used to take the clamps off my Blum machine and used a floor foot pedal.

  10. #10
    Are you talking about something like a pneumatic cope or tenon sled? Grizzly, and Weaver both make nice ones. I have a Ritter pneumatic sled made out of 1 thick aluminum. Lots of ways to do this. I have even seen one shop take a Weaver sled that rode in the miter track and put a long pneumatic cylinder on the back side activated by a foot pedal that would push the sled through the shaper cut and then pull it back out. Pretty neat way to do it.

  11. #11
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    Quote Originally Posted by Bobby Robbinett View Post
    Are you talking about something like a pneumatic cope or tenon sled? Grizzly, and Weaver both make nice ones. I have a Ritter pneumatic sled made out of 1” thick aluminum. Lots of ways to do this. I have even seen one shop take a Weaver sled that rode in the miter track and put a long pneumatic cylinder on the back side activated by a foot pedal that would push the sled through the shaper cut and then pull it back out. Pretty neat way to do it.
    My shaper has a sliding table so I don't need a sled. Just a better way to hold down stock.

  12. #12
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    Ok I have an update on this I came up with a different hold down but it has its own issues. There is too much deflection in the cylinder rod to hold a workpiece securely. If I crank up the air pressure then my mount has deflection. Any ideas on how to improve this?

    20220508_181546.jpg20220508_181526.jpg

  13. #13
    The clamps need to be mounted independent of the fence. The central post of the miter gauge might be stout enough, or you can use other tapped holes in the table to mount brackets. Cam clamps I have used typically have a vertical post with a height-adjustable bracket in which slides a horizontal beam with the clamp at the end, allowing a fair amount of adjustability to get the pressure where needed. Your setup will not do a lot to hold down the far edge of a wide rail. For the narrow part shown you would need to double it up to keep the clamp foot from tilting.

    You will want a backer strip (maybe that is what you are showing) to suppress spelching as the cutter exits the workpiece. Most people screw the backer through the fence. I have found that a fresh backer at every cut works best so I use loose backers and clamp the workpiece and backer horizontally to the fence with some sandpaper glued to the fence. to ensure the backer doesn't get loose.

  14. #14
    You could make wooden “fingers”. Angled board with saw cuts making each about 3/16ths wide. Clamp to fence.

    Or use screws if you use a wooden fence
    Last edited by Mel Fulks; 05-08-2022 at 10:16 PM.

  15. #15
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    I'm not getting any defection of the miter gauge but more of the bracket that I made and the rod of the cylinders. This shaper came with a cam clamp that was mounted to the post on the miter gauge. I never liked that one. It was difficult to adjust to work correctly.

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