Results 1 to 12 of 12
  1. #1
    Join Date
    May 2002
    Location
    San Mateo, CA
    Posts
    5,038

    Default Making accurate compound miter bevel cuts

    I have been making a hexagon hive using a 12" Dewalt radial arm saw and having lots of degree accuracy problems. I did do a tuneup on the saw settings before starting. Twelve cuts with a half degree mistake make for big gaps. Made a lot of firewood trying to get the angles right. What methods could I use on the radial arm to get the degree settings correct? WoodCraft has better protractors and digital devices to hang from the blade, I could buy those for next time. Or do I need a newer sliding miter saw? Would that be more accurate?



  2. #2
    Join Date
    Dec 1999
    Location
    DuPage County, Illinois USA
    Posts
    9,647

    Default Re: Making accurate compound miter bevel cuts

    I doubt your saw needs replacing. As long as you don't have side to side movement in the arm when locked, or in the saw head cradle, it's fine. What might work better in getting the exact angle worked out is to trace out your box on paper/cardboard and divide it up with pencil. Once you have them all equal, then it's just a matter of setting your saw to get one of the pieces correct. Repeat on the rest. I'm not a whiz when it comes to math, but I can always figure out a way to get the end result I want, usually by drawing it first with these sort of things.

    Looking at it again, I can't tell if the top boards are on an angle, making it a compound angle. Duh, you said so in your title, sorry.
    Regards, Barry

  3. #3
    Join Date
    Jan 2005
    Location
    Hamilton, Alabama
    Posts
    1,232

    Default Re: Making accurate compound miter bevel cuts

    In this case, a table saw compound miter sled is a better choice. For a hexagon, you need a 30 degree horizontal angle on the wood and the cut needs to be at 15 degrees vertical (note, looking at your pieces, it looks like you may be using about 20 degrees, adjust accordingly). Cut a piece of plywood big enough to fit over both miter slots on your table saw, cut guides to fit into the miter slots and glue and screw them to the plywood. Run your table saw angle to 30 degrees and make test cuts until you are certain it is cutting the exact angle desired. Then set a test piece on the sled and verify it is properly set to 30 degrees. You will still have to test that it is cutting exact, but it should be close enough that a disk sander can adjust as needed.

    http://www.blocklayer.com/CompoundMiterEng.aspx
    Last edited by Fusion_power; 12-14-2013 at 02:29 PM.
    DarJones - 45 years, 10 colonies (max 40), sideliner, treatment free since 2005, 11 frame broodnest, small cell

  4. #4
    Join Date
    Feb 2012
    Location
    West Bath, Maine, United States
    Posts
    1,143

    Default Re: Making accurate compound miter bevel cuts

    Are you using one of the online compound miter spreadsheets? Twelve compound cuts do add up fast.
    4 yrs, Peak 14, back to zip, T lite; godfather to brother's 3.

  5. #5
    Join Date
    Dec 1999
    Location
    DuPage County, Illinois USA
    Posts
    9,647

    Default Re: Making accurate compound miter bevel cuts

    This has some useful info as well.

    http://www.waterfront-woods.com/fest...ound_Miter.pdf
    Regards, Barry

  6. #6
    Join Date
    Feb 2012
    Location
    West Bath, Maine, United States
    Posts
    1,143

    Default Re: Making accurate compound miter bevel cuts

    In the end it always comes down to scrap wood trials for me. Before or after I try with the good wood.
    4 yrs, Peak 14, back to zip, T lite; godfather to brother's 3.

  7. #7
    Join Date
    May 2013
    Location
    Whitla Ab. Canada
    Posts
    489

    Default Re: Making accurate compound miter bevel cuts

    As an old sheet metal mechanic, the easiest way would be to use triangulation. Once you get the true length of your angles the rest falls into place.
    But every sunday afternoon he is a dirt track demon
    In a '57 chevrolet- Jim Croce

  8. #8

    Default Re: Making accurate compound miter bevel cuts

    I two would make a sled and use the table saw

  9. #9
    Join Date
    May 2002
    Location
    San Mateo, CA
    Posts
    5,038

    Default Re: Making accurate compound miter bevel cuts

    Quote Originally Posted by Saltybee View Post
    Are you using one of the online compound miter spreadsheets? Twelve compound cuts do add up fast.
    I have done rectangle planter boxes for decades, no problems. I have a good chart that came with my saw and online charts. It is the accuracy of the saw that is the problem when going to the hexagon. Everyone I consulted said it is a compounding of a minor setting making the problem. Finished for now, will make a flat roof next time.

  10. #10
    Join Date
    Oct 2010
    Location
    Pueblo, Colorado, USA
    Posts
    723

    Default Re: Making accurate compound miter bevel cuts

    I only make miters and compound miters on the table saw. My radial arm is a really nice (old) saw and I have found it's greatest use is in squaring boards and spinning a dado pack.
    Zone 5a @ 4700 ft. High Desert
    Facebook

  11. #11
    Join Date
    Jul 2011
    Location
    Richardson, TX, USA
    Posts
    84

    Default Re: Making accurate compound miter bevel cuts

    Tilt the head to 30 degrees. Nail a board that is the same size you are using for the hive to the table top. Cut the board. Move the saw head out of the way. Hook your measuring tape on the end of the board and measure back the length of one of your sides. Make a mark on the table top at that point. Remove the board you have nailed down and put a stop at the mark you made. Put your board back on the saw and cut it. Flip it around and cut. You now have the piece you need and you can make a bunch more exactly like that one.

    I love my radial arm saw! Don't buy a sliding mitre saw. That radial arm saw you have will do a lot more.

  12. #12
    Join Date
    Feb 2012
    Location
    West Bath, Maine, United States
    Posts
    1,143

    Default Re: Making accurate compound miter bevel cuts

    If your bearings are worn no amount of jigs or compensation will cut true. Going new is no guarantee of improvement. My new compound miter saw has one true 45 and a pretty close square. Took apart my Craftsman old table saw and found bearing #s. Almost 90 from Sears, less than 20 with #s.
    4 yrs, Peak 14, back to zip, T lite; godfather to brother's 3.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Ads