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How do these t-slot clamps work?

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  • How do these t-slot clamps work?

    How do clamps like this hold down to the table? Does the screw just push off from the bottom of the slot? I've always heard that was bad to do with the chance of breaking the slot.
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  • #2
    If you can't place work holding clamps in T-Slots why have T-Slots at all?

    https://www.miteebite.com/products/t-slot-toe-clamps/

    Comment


    • #3
      Originally posted by Bented View Post
      If you can't place work holding clamps in T-Slots why have T-Slots at all?

      https://www.miteebite.com/products/t-slot-toe-clamps/
      those ones sit on top of the table with a t-nut underneath. The ones in my pic dont sit on top of the table.

      I'm not talking about not using the t-slots, but as far as I know, you're not supposed to push off the bottom of the slot. That would be the same as putting a stud right through a t-nut so that it hits the bottom of the slot.

      what I want to know, is if that's how these clamps work, or if there is some other method I cant see from the pics.

      Comment


      • #4
        Ok I think the setscrew hole, binds the clamp to the table, the black bolt pulls it down and clamps the work.. if the main part of clamp can slide it will not work.
        bottoming a screw in the slot won't hurt things, With MODERATE Torque .

        Comment


        • #5
          Those clamps in the picture- looks like two of them are bolted in place, the workpiece is brought up against them, then the other two are bolted in place with those angled pieces loose. As you tighten the angled pieces, they 'swing' slightly towards the work piece, pushing it against the other two fixed clamps.
          I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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          • #6
            Probably push off of the bottom to keep them lower. There is little difference between pushing a T-Nut up from the bottom or pulling it from the top, over tightening can break the slot either way.

            Do not over tighten.

            Comment


            • #7
              If you're making these style clamps for yourself one trick you can use is to make the T section of the clamps with a slight raised portion at the edges. That'll put most or all of the pressure at the corner of the T slot where it puts most of the pressure into shear instead of bending and tension.

              Sketch below.....

              That's one of the nicer low profile clamp designs I've seen. I think that's the sort I'm going to make soon. With the trick shown below.

              Click image for larger version

Name:	T slot loading.JPG
Views:	370
Size:	69.7 KB
ID:	1884159
              Chilliwack BC, Canada

              Comment


              • #8
                Originally posted by Bented View Post
                Probably push off of the bottom to keep them lower. There is little difference between pushing a T-Nut up from the bottom or pulling it from the top, over tightening can break the slot either way.

                Do not over tighten.
                This is so basic I find it incredible it has to be explained to some people.
                Location: Saskatoon, Saskatchewan, Canada

                Comment


                • #9
                  Originally posted by BCRider View Post
                  If you're making these style clamps for yourself one trick you can use is to make the T section of the clamps with a slight raised portion at the edges. That'll put most or all of the pressure at the corner of the T slot where it puts most of the pressure into shear instead of bending and tension.

                  Sketch below.....

                  That's one of the nicer low profile clamp designs I've seen. I think that's the sort I'm going to make soon. With the trick shown below.

                  Click image for larger version

Name:	T slot loading.JPG
Views:	370
Size:	69.7 KB
ID:	1884159
                  Nicely illustrated.

                  JL..............

                  Comment


                  • #10
                    Originally posted by Arcane View Post

                    This is so basic I find it incredible it has to be explained to some people.
                    I was always taught that the stud never goes all the way through the nut, and that the nut either fits under the part, step block or both. That way the tops of the slots are always in compression.

                    Comment


                    • #11
                      Originally posted by BCRider View Post
                      If you're making these style clamps for yourself one trick you can use is to make the T section of the clamps with a slight raised portion at the edges. That'll put most or all of the pressure at the corner of the T slot where it puts most of the pressure into shear instead of bending and tension.

                      Sketch below.....

                      That's one of the nicer low profile clamp designs I've seen. I think that's the sort I'm going to make soon. With the trick shown below.

                      Click image for larger version

Name:	T slot loading.JPG
Views:	370
Size:	69.7 KB
ID:	1884159
                      Thanks for that. I may try to make something like this. I had just always been taught to never let the stud out the bottom of the nut, and figured this was working the same way.

                      Comment


                      • #12
                        Originally posted by Arcane View Post

                        This is so basic I find it incredible it has to be explained to some people.
                        If the part or step block is over the t-nut, you can tighten until you snap the stud. All you are doing is squeezing cast iron.

                        It's when the t-nut is out in the middle between the part and the step block that you get trouble. Then you are pulling up on the t-slot, and nothing is pushing on top. That's why the stud should be right up next to the part (the other reason is because then the tightening is directly acting on the part, no force wasted busting t-slots)

                        1601

                        Keep eye on ball.
                        Hashim Khan

                        Comment


                        • #13
                          Just don't overtorque, it's that simple.,
                          Sometimes I want the stud to hit bottom, I may not want it to move when changing parts. Other times I want it to slide away for loading or unloading parts.
                          MANY DIFFERENT scenarios in the hours I have stood by a mill working.. . Do what needs to gd done without harming the equipment, just use common sense.

                          Comment


                          • #14
                            Originally posted by Dragons_fire View Post

                            Thanks for that. I may try to make something like this. I had just always been taught to never let the stud out the bottom of the nut, and figured this was working the same way.
                            I've looked around at low profile clamps quite a bit now and many of the lowest profile designs rely on one or more of the screws used to lock the clamps biting into the base of the T slots in the same manner as the ones in the opening post. After all the point of a low profile clamp is to be low profile so there's really no room for a top block or plate that serves to clamp the sides of the T slot.

                            One option for such low profile clamps could be to have a second locking block that comes in behind the one as shown and uses a second locking screw. That way the pressure is spread out more and neither setscrew needs to be overly tight. The need for two instead of simply one longer clamp is that the little access well on the ends of the table only allows for limited length T nuts or fittings to be inserted.

                            Basically go back and look at the clamps in that first picture and imagine a more or less regular T nut but with a set screw instead of being used with a stud so the last thread is beaten closed. This "backing block" T nut would let us secure the low profile clamp shown with shared force over a wider part of the T slot. So we could achieve the desired locking force over more area and with less torque needed on each screw. So less risk to the T slots.

                            And as pointed out a few times already just don't tighten the snot out of them. But having that second backing block would make it easier to justify using the lower torque.
                            Chilliwack BC, Canada

                            Comment


                            • #15
                              I haven't used those, but I would guess that the set screw is just to hold the clamp in place while identical parts are replaced. They are not supposed to be very tight. The cap screw on the clamp portion pushes that clamp arm down while drawing the Tee nut up. So the table is pinched between the work piece and the Tee nut's wings.

                              Anyway, that's my guess. And it is how I would make them.



                              Originally posted by Dragons_fire View Post
                              How do clamps like this hold down to the table? Does the screw just push off from the bottom of the slot? I've always heard that was bad to do with the chance of breaking the slot.
                              Paul A.
                              SE Texas

                              Make it fit.
                              You can't win and there IS a penalty for trying!

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