cutting acute angles safely

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  • poolhound
    Veteran Member
    • Mar 2006
    • 3195
    • Phoenix, AZ
    • BT3100

    cutting acute angles safely

    I am about to start a project where I will need to cut a bunch of small acute angles < 30 degrees. To make it trickier many of them need to be on stock 6' long.

    My CMS cant be set for much less than 40 the SMT around 35 and the miter gauge on my BS at 30.

    The options I have come up with all require angled support jigs that will let me either

    a) use the rip fence on either the TS or BS
    b) attach to the CMS fence to get the correct angle
    c) use the BS miter gauge or SMT

    What have any of you folks done to solve this problem and which do you think would be the easiest and safest way to go?
    Jon

    Phoenix AZ - It's a dry heat
    ________________________________

    We all make mistakes and I should know I've made enough of them
    techzibits.com
  • pelligrini
    Veteran Member
    • Apr 2007
    • 4217
    • Fort Worth, TX
    • Craftsman 21829

    #2
    I've used an additional 45 degree angle between the piece and the SMT fence on my tablesaw. Much like back when hand drafting when combining a 45 and a 60 to get other desired angles. I don't have a CMS, so I never tried a solution there.

    A speed square clamped to the miter fence and the piece clamped to it makes for a quick & dirty cut. I used to have a simple jig of ply & 1x material making a nice clampable (and much safer) 45 degree. It got taken apart for use in something.
    Erik

    Comment

    • LarryG
      The Full Monte
      • May 2004
      • 6693
      • Off The Back
      • Powermatic PM2000, BT3100-1

      #3
      For stock 6' long, I'd be thinking in terms of moving the tool rather than moving the workpiece, if possible. That points toward your choice "b) attach to the CMS fence to get the correct angle."

      But how wide is the stock, and what is the capacity of your CMS? A 30deg cut on a 1x8 (7-1/4" actual) will be 1'-2 1/2" long. On my 12" non-slider, with roughly a 9 1/4" crosscut capacity, I'd be limited to stock about 4 1/2" wide at that angle.

      EDIT to ask two more questions: what is the material, and how many pieces do you have to cut?
      Last edited by LarryG; 08-05-2008, 11:48 AM.
      Larry

      Comment

      • poolhound
        Veteran Member
        • Mar 2006
        • 3195
        • Phoenix, AZ
        • BT3100

        #4
        Originally posted by LarryG
        For stock 6' long, I'd be thinking in terms of moving the tool rather than moving the workpiece, if possible. That points toward your choice "b) attach to the CMS fence to get the correct angle."

        But how wide is the stock, and what is the capacity of your CMS? A 30deg cut on a 1x8 (7-1/4" actual) will be 1'-2 1/2" long. On my 12" non-slider, with roughly a 9 1/4" crosscut capacity, I'd be limited to stock about 4 1/2" wide at that angle.

        EDIT to ask two more questions: what is the material, and how many pieces do you have to cut?
        I am still working on the design but I would say that the widest would be no more than 3". The material is Walnut and how many is tough to say at this point (still design dependent). Not a huge number i.e 100s but somewhere between 6 and 20 something.

        The basic concept design as you may have guessed is a triangular structure, hence lots of acute angles that must be repeated.
        Jon

        Phoenix AZ - It's a dry heat
        ________________________________

        We all make mistakes and I should know I've made enough of them
        techzibits.com

        Comment

        • pecker
          Established Member
          • Jun 2003
          • 388
          • .

          #5
          Maybe cobble together a jig/guide for a handheld circular saw. This jig/guide could incorporate a shooting board (look it up) so you could true up all your cuts with a hand plane, if you needed a more accurate cut than your circular saw provides.

          I have something like this one...

          but you could easily make something out of scrap for one specific angle.


          You can also make something more elaborate to provide more support for the stock. Sort of like this picture, but with your guides at the prober angle.

          Comment

          • LarryG
            The Full Monte
            • May 2004
            • 6693
            • Off The Back
            • Powermatic PM2000, BT3100-1

            #6
            For 3" wide pieces, I'd probably use my CMS. For a 30deg cut, a 15deg wedge against the fence would bring the blade angle within the 45deg range of my saw.

            Alternatively, and especially for wider workpieces that might not fit on the CMS, I was going to suggest something similar to what pecker shows. A number of the workpieces could be ganged together, side by side and with the ends staggered to minimize waste, with a straightedge laid across them to guide a circular saw. Make the rough cut with the CS; then adjust the straightedge position as required to make a cleanup pass with a router loaded with a straight bit. (Add a piece of scrap at both edges, to control blowout.)
            Larry

            Comment

            • billvan
              Handtools only
              • Jan 2007
              • 2

              #7
              see link:

              Comment

              • cabinetman
                Gone but not Forgotten RIP
                • Jun 2006
                • 15218
                • So. Florida
                • Delta

                #8
                Originally posted by poolhound
                I am still working on the design but I would say that the widest would be no more than 3". The material is Walnut and how many is tough to say at this point (still design dependent). Not a huge number i.e 100s but somewhere between 6 and 20 something.

                The basic concept design as you may have guessed is a triangular structure, hence lots of acute angles that must be repeated.

                Posting a picture or a sketch of your intent would provide a better understanding of your dilemma. What's the difficulty in cutting angles less than 45 degrees on the end of a 6' piece 3" wide on a MS or CMS?
                .

                Comment

                • pelligrini
                  Veteran Member
                  • Apr 2007
                  • 4217
                  • Fort Worth, TX
                  • Craftsman 21829

                  #9
                  I believe the problem is cutting an angle less than 45 degrees when measured from the long side. 90 would be a crosscut, 30 would be difficult.
                  Erik

                  Comment

                  • shoottx
                    Veteran Member
                    • May 2008
                    • 1240
                    • Plano, Texas
                    • BT3000

                    #10
                    Jon

                    If you are asking what I think you are asking, any way, here is a quick jig I put together on Monday to make a set of feet for a project. This jig was constructed at 15 deg.

                    To construct the jig, I trued up two pieces of scrap about 30" and cut the angle I desired on one end using a hold down and a backer board on the CMS. The rest was pretty straight forward.

                    You will neeed some sort outfeed support for 6' pieces. The other consideration is ensuring the boards you are cutting will clear the fence from the starting point.. (don't ask why I know that is important)

                    And here is the pictur with a piece of walnut for illustration.
                    Attached Files
                    Often in error - Never in doubt

                    Mike

                    Comment

                    • LCHIEN
                      Internet Fact Checker
                      • Dec 2002
                      • 20914
                      • Katy, TX, USA.
                      • BT3000 vintage 1999

                      #11
                      Attaboy, Mike (Shoottx) that's the way I'd do it.

                      That's just a bigger version of the ones you can buy, like this adjustable one from Rockler:



                      HF has one too, almost identical for half the money.

                      I don't see how you can cut this on a MS or CMS unless it was a slider...
                      Last edited by LCHIEN; 08-06-2008, 11:58 AM.
                      Loring in Katy, TX USA
                      If your only tool is a hammer, you tend to treat all problems as if they were nails.
                      BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

                      Comment

                      • poolhound
                        Veteran Member
                        • Mar 2006
                        • 3195
                        • Phoenix, AZ
                        • BT3100

                        #12
                        Originally posted by cabinetman
                        Posting a picture or a sketch of your intent would provide a better understanding of your dilemma. What's the difficulty in cutting angles less than 45 degrees on the end of a 6' piece 3" wide on a MS or CMS?
                        .
                        As pelligrini stated its cutting small angles on the long edge. between around 35-45 isnt too bad but I need angles in the 20s.
                        Jon

                        Phoenix AZ - It's a dry heat
                        ________________________________

                        We all make mistakes and I should know I've made enough of them
                        techzibits.com

                        Comment

                        • LarryG
                          The Full Monte
                          • May 2004
                          • 6693
                          • Off The Back
                          • Powermatic PM2000, BT3100-1

                          #13
                          Originally posted by shoottx
                          The other consideration is ensuring the boards you are cutting will clear the fence from the starting point.
                          This is the main reason I wondered how well a solution on the TS would work. Jon said he needed angles less than 30deg, but he didn't say how much less (and he didn't say how wide, either). I questioned whether there'd be room to keep the rip fence on the rails with a 6' long workpiece.

                          A big advantage of your method is that, even though the workpiece is moving, there's a lot more table area to support it than there would be trying to make the same cut on the typically miniscule tables of a miter saw. And the outfeed support problem is minimal since it's a narrow workpiece that won't have to move very far. All things considered, yours might well be the better method.
                          Larry

                          Comment

                          • LCHIEN
                            Internet Fact Checker
                            • Dec 2002
                            • 20914
                            • Katy, TX, USA.
                            • BT3000 vintage 1999

                            #14
                            In my opinion the jig that Shoottx suggests can be made safer.
                            The workpiece is pushed forward by the lip at the bottom.
                            The scary part is either letting the workpiece go with no hold down pressure or using your hand within a couple of inches of the blade.
                            Here's how you make it safer:
                            Put a piece of rectangular plywood under that jig, attached to the bottom of the arms. It should be as long as the jig and a tad wider than the fence to blade width.
                            One edge should be against the fence and flush with the right arm.
                            When you cut, the plywood will be trimmed at the saw blade of course. But the dangerous part of holding the workpiece as you slide it within inches of the blade can then be accomplished with a pair of hold down clamps mounted to the arm of the jig adjacent to the workpiece. You'll have to raise the blade the extra height of the thickness of the plywood.
                            Loring in Katy, TX USA
                            If your only tool is a hammer, you tend to treat all problems as if they were nails.
                            BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

                            Comment

                            • poolhound
                              Veteran Member
                              • Mar 2006
                              • 3195
                              • Phoenix, AZ
                              • BT3100

                              #15
                              Thanks to all,

                              We all agree that some form of jig or support is needed to alter the angle of attack e.g. for a 15 deg cut using a CMS make a 45deg wedge and set the CMS at 30.

                              I am leaning towards something that the workpiece can be attached to and run along a fence similar to what Mike just posted (thanks). Once I finish the design and get to the shop this weekend I will see what works out easiest, safest and most accurate.

                              FYI - the project is for an "Ark" for a local temple. You know how it goes, somebody who knew somebody who knew me told them I am a woodworker, so I get a phone call, "how would you like to build us......"

                              The design is centered around the "star of David" which is essentially 2 reversed triangle. The pic here shows the basic concept.
                              Attached Files
                              Jon

                              Phoenix AZ - It's a dry heat
                              ________________________________

                              We all make mistakes and I should know I've made enough of them
                              techzibits.com

                              Comment

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