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Thread: Zero clearance insert for Bosch GCM12SD

  1. #1
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    Zero clearance insert for Bosch GCM12SD

    Does anyone have a contact for a zero clearance insert for a Bosch GCM12SD miter saw?

  2. #2
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    Don't have a zci 'contact' for your saw but if you're in a pinch, Fastcap has zc-tape.

    https://www.fastcap.com/estore/pc/vi...dproduct=51659

  3. #3
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    Or just do this . . .

    worn zci sm.jpg

    I make them like any other saw's ZCI.
    "A hen is only an egg's way of making another egg".


    – Samuel Butler

  4. #4
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    Glenn, what material do you use and what's your source? What you show is what I'm looking for. Thanks.

    Jeff

  5. #5
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    Anyone know what material Fastcap is actually using for these? Id love to buy a roll of red to match my Bosch's insert and not yellow.
    If at first you don't succeed, redefine success!

  6. #6
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    Question Perhaps you can educate me...

    Quote Originally Posted by Jeff Ramsey View Post
    Does anyone have a contact for a zero clearance insert for a Bosch GCM12SD miter saw?
    It is not the first time I read about people looking for zero clearance insert for miter saw and I cannot get why.

    I can understand the value for cut quality (even losting some operational security) for zero clearance insert for a regular table saw as the teeth came up to down against the piece to be cut so if you provide some additional support bellow the piece being saw, you can get clearer cuts... but it does not look the case for your Bosch saw as the saw teeth will go upwards so you can have problems on top of the sawing piece, not below it... a zero clearance insert for your saw apparently will add nothing to the saw functionality and cut quality.

    I am planning to go to that saw somewhere in this year, so your comments are particularly welcome!

    Thanks in advance for any input.
    Last edited by Osvaldo Cristo; 01-02-2017 at 3:05 PM.

  7. #7
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    The saw blade turns the same direction on both the miter saw and table saw and thus will chip out on the bottom, if not properly supported by a ZCI. I agree the ZCI on a miter saw will do nothing to prevent chip-out on the top, but that should be minimized.

  8. #8
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    I use them to prevent smaller cutoffs from dropping into the slot, a freshly cut ZCI also allows for quick eyeball alignment for certain cuts where the reference mark can go on the table.

    I also make up a full zero clearance setup for the table and the fence when needed for precise repetitive cuts on smaller stock.

    While the ZCI for a miter type saw doesn't particularly increase the quality of the cut it can be useful for the accuracy of the cut.

  9. #9
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    Thanks for your fast answer!

    Quote Originally Posted by Jeff Ramsey View Post
    The saw blade turns the same direction on both the miter saw and table saw
    Agree.

    Quote Originally Posted by Jeff Ramsey View Post
    and thus will chip out on the bottom
    It looks me odd as the piece will be in different positions relative to the saw blade: upside for table saw and downside for miter saw. At the same way the cut piece will have a tendency to chip out at bottom in a table saw (so the ZCI can effectively add some benefits in the cut quality), when at a miter saw it will have a tendency to chip out in the top face of the piece.

    The cut on the upward surface in a table saw or downward surface in a miter saw looks me OK and not subject to the chip out that the opposite faces will support.

    Sorry for my insistence (I am a little bit slow to learn) but I cannot see an effectiveness for ZCI in a miter saw.

    Thanks again!

  10. #10
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    Quote Originally Posted by Tom Ewell View Post
    I use them to prevent smaller cutoffs from dropping into the slot, a freshly cut ZCI also allows for quick eyeball alignment for certain cuts where the reference mark can go on the table.

    I also make up a full zero clearance setup for the table and the fence when needed for precise repetitive cuts on smaller stock.

    While the ZCI for a miter type saw doesn't particularly increase the quality of the cut it can be useful for the accuracy of the cut.
    +1 on that. It's also faster and more precise than a laser (for me personally). Could just be my over 50 eyes.

    Also, when cutting wide boards on a SCMS if one is pulling the saw out, plunging the blade, then cutting away from the operator the initial plunge can blow out the bottom of the board. I have seen some guys use a SCMS in a RAS fashion in which case the entire cut will blow out the bottom. Kind of depends on the material, which side is up and which direction one is cutting.

    As for sourcing ZCI's, I make my own. Baltic birch.

  11. #11
    The top side of the board has solid wood below the fibers that would be subject to heavy tear out. With a sharp blade, the top side tear out should be minimal. The exit points for the blade (under and fence) are subject to much worse tear out when those fibers are not supported by a ZCI and sub fence. For this reason all of my miter saws have a ZCI and a sub fence. ZCI's made of plywood and sub fences of MDF or plywood.

    If you need top side protection, score the line.

  12. #12
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    Quote Originally Posted by Tom Ewell View Post
    I use them to prevent smaller cutoffs from dropping into the slot, a freshly cut ZCI also allows for quick eyeball alignment for certain cuts where the reference mark can go on the table.
    I like both of those reasons. I have the Bosch 12" glide with a Forrest Chopmaster blade and still get a small amount of chipout on the bottom. Most of it should be at the front of the workpiece where the blade travels down before the push cut. The biggest chipout is on the back where there is a 1-2" gap to allow the blade to tilt. A disposable ZCI for the back fence would be even more helpful.

    Steve

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