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  • Dado Sacrificial Fence

    I think I understand the reasons for using a sacrificial fence when making dados on the table saw. Keeping the blades away from the saws fence and to allow me to make rabbet cuts in board edges without making multiple passes with a sigle blade seem to be the main ones. If there are others can some one please educate me?

    My questions are,
    How do I securely clamp the sacrificial fence to the saw fence without interfering with the cutting process? I once saw a clamp that looked lika a c-clamp out of round stock where the top of the C was a little shorter than the bottom which had the screw mechanism and you would drill a hole in the top of the fence for the shorter top leg of the clamp to fit into and then tighten screw to the back side of fence.

    Is it really safe to raise the dado blade up into the sacrificial fence?

    And is there a procedure that must be followed to do so?

    I assume a non reactive manmade product like MDF is a good material for the fence?

    Assuming 3/4 stock for the sacrificial fence. Is there a rule of thumb for the widest dado thickness I can completely bury in it?

    Assume a 3/8" dado 3/16" deep. I make a sac fence for this cut. Next dado will be 1/2"w x 5/16"d. Do I make another sacrificial fence or repurpose the first one?

    Can anyone please shed some light on this mystery?
    Hector




  • #2
    Re: Dado Sacrificial Fence

    I know the fence clamp you're talking about. I think it was in Wood magazine's review of some "gotta have" gadgets, but the name escapes me right now. I'll see if I can find it. If I recall they were about $25 for a pair, and are pretty slick.

    I saw a reader-submitted article somewhere about sacrificial fences. What this guy did was create a three-piece fence. The center section was removal and replaceable. By beveling the angles on the outside pieces and the center piece, it was possible to slip the center section in and out without removing the outer pieces. Essentially it was a dovetail type of setup. Very cool, and a great idea I have yet to find time to implement.

    Anyway, with regards to some of your questions..
    You could use regular clamps to attach a piece of 3/4" MDF securely to your fence and off you go. That's what I do on the rare occasion I do a rabbet using the TS. Normally I prefer using the router. The only hindrance of regular clamps is that you can't run tall material.

    You should definitely reuse and repurpose sacrifical fences. The main purpose is just to give the blade somewhere to "hide" and prevent damage to your stock fence. Preventing tearout is a secondary advantage.
    In your example, I would definitely repurpose the fence and cut the second rabbet using the same fence.

    As far as a maximum dado blade width, that partly depends on your comfort level of getting the spinning-blade-of-doom really close to your stock fence.

    If you're using 3/4" MDF, the absolute widest penetration of the fence I would personally recommend is 5/8". That gives you 1/8" clearance from your lovely aluminum stock fence.

    If you decide to use 3/4" plywood for a sac fence, please remember that plywood is undersized, and doing a 5/8" penetration really only leaves you with about 2/32" of clearance.

    But really, there's no reason at all to bury 5/8" of your dado blade making a rabbet. If you just want a 1/4" rabbet, make your dado 1/2" wide, and bury it 1/4" in the fence.

    Comment


    • #3
      Re: Dado Sacrificial Fence

      Hey Hector. I have gone through the same process recently! I finally made a sacrificial fence for the 3650 using some scrap 3/4" stock I had laying around. It was milled flat enough, and the project wasn't that tight on tolerance, so the fence didn't have to be dead-on flat. Next one I do, however, I'm going to use MDF. Just seems that, when making dados, a real good flat fence (to make real nice straight dados) is going to be a requirement!!

      To attach the piece to the fence, I drilled and countersunk 3 holes. Using the three left-over bolts from the saw (and being amazed that I could still find them...), I mounted the sac fence to the Ridgid fence. I countersunk the holes in the 3/4" scrap enough to bury the nuts into the fence so they couldn't hang up the work. That's also why 3/4" is about the thinnest I'd make the sac fence. You need that thickness there so you can sink the hole for the nuts, and still have enough material to hold.

      hmmmm....this is beginning to sound weird. I should just stop here... I think you get the jist of what I'm saying.
      I put it all back together better than before. There\'s lots of leftover parts.

      Comment


      • #4
        Re: Dado Sacrificial Fence

        Thanks W_J. for clarifying things for me. It all starts whirling around in there and nothing seems to make sense after a while. I'll put this info to good use.

        And Sandy, it didn't sound weird to a woodworker at all. I understood everything you said and meant. Now I jist(love that word) have to get off my but and do it. Off to the shop to make some sawdust. Thanks for the replies. Later,
        Hector
        Last edited by Hector B; 06-07-2007, 05:00 PM.

        Comment


        • #5
          Re: Dado Sacrificial Fence

          I often use a backward L shaped sacrificial fence. Make the vertical part as tall as the fence, the horizonal part juts out 2 inches or so to the left. Standard F clamps will hold the vertical portion to the fence and not get in the way of the cutting.

          Comment


          • #6
            Re: Dado Sacrificial Fence

            I just made one last night for cutting rabbets. I made my sac fence out of a 2X6 and used toilet bolts to fit in the slots on the fence. Then I drilled a hole for teh bolt to correspond with the fence slots and then drilled a 1" wide hole with a forstner bit on the face to allow me to use a washer. I then cut the toilet bolt so that it was just under the fence (about 1/8" or so). (I hope the pic uploaded.)


            I think the best way to fabricate a sac fence for the 3650 or the 2400 fence would be to make a sac fence that covered the fence with mounting bolts either on the top slots or the opposite side you are cutting on. This way you could use 1/2" or 3/4" MDF for the fence. One side could be for cutting rabbets, like I show here, and the other could be for regular cuts. I plan to do this as soon as I get my outstanding orders completed.

            Comment


            • #7
              Update:Re: Dado Sacrificial Fence

              I don't know why I kicked up all the fuss. A piece of 3/4 MDF, with a 1/8X1/8 rabbet on the bottom edge facing the blade, clamped to the fence worked out great for all my 1/2" rabbets. Then burying a 1/2" dado setup into the fence for the 1/4" rabbets went smooth as silk. What was I worried about? Over cautious I guess. Thanks for all the support. So much to learn and so little time....
              Hector

              Comment


              • #8
                Re: Dado Sacrificial Fence

                Rockler has them for $14.99 a set. They're called uniiversal fence clamps.

                Comment


                • #9
                  Re: Dado Sacrificial Fence

                  Here is how I used to do it.

                  Make a box that fits snugly over the entire fence, blade side, other side, end and front. Put a wood top on it for ridgidity. When needed, just grab it and drop it over the whole fence and start cutting. No screws, bolts or clamps. Make the blade side as thick as you want and you can bury any size dado into it!

                  Mark
                  Congratulations to Mr. "the sky is falling" Al Gore, nominated the new Village Idiot!

                  Comment


                  • #10
                    Re: Dado Sacrificial Fence

                    Originally posted by The Wood Meister View Post
                    Here is how I used to do it.

                    Make a box that fits snugly over the entire fence, blade side, other side, end and front. Put a wood top on it for ridgidity. When needed, just grab it and drop it over the whole fence and start cutting. No screws, bolts or clamps. Make the blade side as thick as you want and you can bury any size dado into it!

                    Mark
                    That's what I do as well, except I have a piece of MDF screwed to the blade side so it can be easily replaced whenever I need it.
                    ‎"I've never let my schooling interfere with my education" -Mark Twain

                    Comment


                    • #11
                      Re: Dado Sacrificial Fence

                      I also ordered a set of these universal fence clamps from Rockler and they work great. Once you have a board for a sac. fence, you just drill 2 holes on top to attach the clamps and it's done!
                      Attached Files

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                      • #12
                        Re: Dado Sacrificial Fence

                        I need to get a couple pair of those. They look to be just the ticket for the table saw and probably the bandsaw. Thanks and see ya when the dust clears,
                        Hector

                        Comment


                        • #13
                          Re: Dado Sacrificial Fence

                          Look on the Rockler web site for universal fence clamp. 14.99 a pair. These will sol hold your sacrificial fence on without getting in the saws blades way

                          Comment


                          • #14
                            Re: Dado Sacrificial Fence

                            Sorry for the reply. I see someone else answered with pix and all...

                            Comment


                            • #15
                              Re: Dado Sacrificial Fence

                              All tips gladly accepted and appreciated. Welcome to the forum Av8r.
                              See ya when the dust clears,
                              Hector

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