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Thread: Help with accurate 45 degree corners..

  1. #16
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    I use a jig like the one shown by Rick and cut pieces on the left and right side. After purchasing my Kreg miter gauge, I tend to use it as the cuts come out accurately. I usually cut them intentionally about 1/4-3/8 inch longer than needed. If I need to adjust the angles a bit, the extra length allows me several adjustments. I check the length of pieces on opposite sides by standing the sharp corner on my saw table and putting them back to back to see how close the tips come to each other. You can easily see differences as fine as 1/64". It is critical to proper fit up that opposite sides be exactly the same length. Once I verify that I have the angles right, I can trim the pieces to the correct final length.
    Last edited by Lee Schierer; 01-13-2012 at 8:49 AM.
    Lee Schierer
    USNA '71
    Go Navy!

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  2. #17
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    Jan 2006
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    I use a sled very similar to the one Rick built. I need some help remembering from some older members here. There was a gentleman that used to post alot of jigs and techniques, he has unfortunately passed away....I cannot remember his name. He posted the build process for a 45 degree mitre sled. I built one a few years ago, it took maybe an hour to accomplish. This sled is deadnuts accurate for building anything with 45 degree corners. I used it for table tops, picture frames, square frames, rectangle frames, it never let me down.
    A bus station is where a bus stops. A train station is where a train stops. My desk is a work station.

  3. #18
    I think that the idea with the miter sled it to cut one board on one side, the other on the other side, so that as long as the boards of the sled are at 90 to each other, the miter will match up even though the angle may be slightly off of 45.

  4. #19
    Join Date
    Mar 2011
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    Hudson, MA
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    Here's another video about making a 45 degree miter sled for the table saw
    http://www.youtube.com/watch?v=lXLeMVAkSIY

  5. #20
    Millers-Falls miter box with Disston saw. Perfect every time.
    I do it right, cause I do it twice.

  6. #21
    Join Date
    Jan 2009
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    Connecticut
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    Rick,
    When you use a miter sled like this, Do you put both mating pieces on the sled at the same time so the blade cuts on the joint on both at once. Or, is each piece done seperately? I figured if you do both at once, each hand can hold one piece in place on the support as the sled is pushed through the blade.


    Quote Originally Posted by Rick Thom View Post
    Two essential jigs for me.
    Miter sled makes exact 45 deg cuts every time. Use a stop block to ensure opposing sides are identical in length.
    Cross-cut panel sled. Cuts exact 90 deg. http://thewoodwhisperer.com/the-cross-cut-sled/ is a good one and easy to make IME
    Worth the hour or so to make them, and then use them with confidence for years to come.

  7. #22
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    Quote Originally Posted by Michael Ginsberg View Post
    Rick,
    When you use a miter sled like this, Do you put both mating pieces on the sled at the same time so the blade cuts on the joint on both at once. Or, is each piece done seperately? I figured if you do both at once, each hand can hold one piece in place on the support as the sled is pushed through the blade.
    You cut one piece at a time, just make sure that you cut the mating corners on opposite sides of the jig. If you tried to do two at once the waste would interfere with the other piece you are trying to cut.
    Lee Schierer
    USNA '71
    Go Navy!

    My advice, comments and suggestions are free, but it costs money to run the site. If you found something of value here please give a little something back by becoming a contributor! Please Contribute

  8. #23
    Join Date
    Jan 2006
    Location
    Grand Forks, ND
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    I will try to explain this as best I can. I drew up a quick sketch to try to help. Lets say we want to build a table top frame that is 12" square and the frame is 3" wide.

    The colors that are represented
    Green is the workpiece.
    Yellow is an offcut that MUST be the same width as your workpiece (in this case 3", any length)
    Purple is just a thin scrap that is glued or pin nailed to the yellow offcut.

    mitre sled (324 x 302).jpg

    1. Start with 4 pieces of stock 12 1/8" long by 3" wide. The 1/8 is added as this is the width of the blade kerf, 1/16" will be removed on each cut, as a result you will loose 1/8" of your desired dimension.

    2. Lay out the 4 pieces and number the corner joints (I also like to draw a 45 with the pencil and color out the area I want to remove, makes it easier to keep everything in order)

    3. Your cuts will be made with all the number joints facing up, every corner will have 1 cut on the left side and 1 on the right, results in a perfect 90 degrees.

    4.Slide your workpiece and the offcut to the top of the triangle, the scrap you have attached to the offcut will stop the workpiece exactly in the middle of the kerf. This will result in the loss of the 1st 1/16".

    5. I attach 2 toggle clamps to the triangle 1 for left cuts and 1 for the rights. Once you have the workpiece referenced you can clamp it down and remove the offcut, now make your cut. I will make all my left cuts 1st and then the rights.

    This system has been very reliable, very accurate and very simple to do, just remember to add 1/8" to the overall dimensions and you are good to go.

    I hope this helps you out.
    A bus station is where a bus stops. A train station is where a train stops. My desk is a work station.

  9. #24
    Join Date
    Nov 2006
    Location
    NE Ohio
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    I need some help remembering from some older members here. There was a gentleman that used to post alot of jigs and techniques, he has unfortunately passed away....I cannot remember his name. He posted the build process for a 45 degree mitre sled
    Nissim Avrahami (Nikki)?

    A true creative genius.
    Sadly, a lot of what he posted was done with links to an online service that hosted the pictures. Quite a bit of his hard work has been lost.

  10. #25
    Join Date
    May 2009
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    Boston
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    There was an article in FWW a few years ago where the guy made the frame going clock wise or counter and then fitting the last miter by hand if necessary. Never tried it but it seemed like a good plan.
    Don

  11. #26
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    Quote Originally Posted by Rich Engelhardt View Post
    Nissim Avrahami (Nikki)?

    A true creative genius.
    Sadly, a lot of what he posted was done with links to an online service that hosted the pictures. Quite a bit of his hard work has been lost.
    Bingo, thanks Rich!!! I had his links saved on my old computer as he was truly a creative genius. I miss his posts and kindness. I built a couple of his jigs and sleds, all worked like a champ.
    A bus station is where a bus stops. A train station is where a train stops. My desk is a work station.

  12. #27
    Join Date
    Aug 2011
    Location
    NW Missouri, USA
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    Look very closely at your joint. A miter cut side loads a blade, pushing it away where the load is greatest resulting in a concave cut line. If so, use a sharper, stiffer blade. Also check for vertical squareness to see if the joint is making contact on the back and leaving as gap at the face. Third, seasonal humidity can change the width of a 3" board enough to open a miter. Draw it full scale, increase the width of each board 1/32" while leaving the length the same and watch the gap open at the outer corner big enough for a dime to fall in.

  13. #28
    Join Date
    Mar 2005
    Location
    Pickering, Ontario.
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    339
    Quote Originally Posted by Gary Kman View Post
    Look very closely at your joint. A miter cut side loads a blade, pushing it away where the load is greatest resulting in a concave cut line. If so, use a sharper, stiffer blade. Also check for vertical squareness to see if the joint is making contact on the back and leaving as gap at the face. Third, seasonal humidity can change the width of a 3" board enough to open a miter. Draw it full scale, increase the width of each board 1/32" while leaving the length the same and watch the gap open at the outer corner big enough for a dime to fall in.
    Gary, just a few additional thoughts for miters on wider boards...
    - one of the advantages to the miter sled is the defined saw kerf in the bed of the sled. If you only use blades of the same kerf width... either thin or regular kerf, and always ensure your blade is set exactly on 90 deg ( I use a digital angle gauge fwiw) it is quite easy to hit your cut line for length on your stock right on because you can clearly see the intersection of the stock and the edge of the blades kerf.. no guessing required.
    - for any stock where a fine cut is required, isn't it a good idea to sneak up on the final cut?.. maybe you make several miter cuts to relieve any internal tension/movement with the last one being the money cut.
    I like the idea of the kerf cuts on the backside of the wider stock to help control seasonal movement (see pic). In some cases it would be unacceptable appearance-wise but others, ok.
    Maybe some of these ideas would help.
    Attached Images Attached Images
    • File Type: jpg 6.jpg (16.3 KB, 7 views)

  14. #29
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    Jan 2009
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    Connecticut
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    Thanks for all your input!!!

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