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Thread: Burned bevel cuts: update with Pics

  1. #1
    Join Date
    Dec 2006
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    Spokane, WA
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    Burned bevel cuts: update with Pics

    I'm having trouble cutting bevels on my table saw, with blade tilted to 45*, pushing 3/4" stock through with a Jess-Em slider. Saw is set up to tight tolerances, with no burning for any other cuts. I need to cut some 1 1/2 x 3/4" banding for my drill press table, thought this would be the best way to do it. All goes well until the piece gets about half way through the blade, then it burns the top 1/4" or so of the workpiece, not the off cut , only where the teeth stand proud of the blade. It's a fairly new Freud fusion blade, which performs very well on other cuts. I figure the blade must not be aligned to the table in the 45* position, (it's within about .001 or so when 90* to the table) but how does one go about adjusting that? I'll check it with my dial indicator tomorrow. I have a 2 year old left tilt Delta Unisaw. Thanks much.

    Dan
    Last edited by Dan Forman; 02-21-2007 at 09:02 AM.
    "A dog teaches a boy fidelity, perseverance, and to turn around three times before lying down."
    Robert Benchley

  2. #2
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    Remembering that I have some issues with flatness of the top on my saw, I went down and checked it, and sure enough, there is a bit of a hump in the top running from side to side, right even with the arbor. It's enough to hear the audible clicks as I rock the straight edge back and forth on the saw table. So my guess is that the blade is aligned ok, but the undulation in the top is pushing the workpiece up into the teeth of the blade after the initial cut is made. Is this a reasonable assumption, and is there anything to be done about it?

    Dan
    "A dog teaches a boy fidelity, perseverance, and to turn around three times before lying down."
    Robert Benchley

  3. #3
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    80-120-220? or a machinist .....
    [SIZE="1"] associated with several importers and manufacturers.[/SIZE]

  4. #4
    Join Date
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    A big flat file laying on the table and some time. Just take you time and work down the high spot. Then as Tod said, start polishing it with the sand paper. Slow process but it will work.
    God grant me the senility to forget the people I never liked anyway,
    the good fortune to run into the ones I do,
    and the eyesight to tell the difference.


    Kudzu Craft Lightweight Skin on frame Kayaks.
    Custom built boats and Kits

  5. #5
    Join Date
    Dec 2006
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    Punta Gorda, Florida
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    Your Uni has a hump and mine has a dip. I think that the hump would be easier to correct. The table top quality in the last few years leaves a lot to be desired. That is the only thing that I do not like about the saw. I would never by a new one again unless I was able to check to top before purchase.

  6. #6
    Hi Dan, first thing I would check is the blade parallel with the miter slot at 45. even if its parallel at 90, it can toe in or out when you tilt the arbor. Then check the trajectory of the sliding table to the same miter slot. Are you clamping the peices when you cut them? Bevels have a tendancy to pull the piece into the side of the blade, hope this helps.

  7. #7
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    Dec 2006
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    Sorry I couldn't get back to this thread any earlier. Please bear with this post, as it is a copy posted at another forum as well, so some things may be repeats, but there is new stuff too, plus a few pics.

    Jay---You are right on, as far as the blade not being parallel to the right miter slot, as described later in this post. I guess the cure for that is shimming between the cabinet and the saw table. But the hump may also come into play. The fence of the sliding table has sandpaper facing, so I don't think the wood is getting pulled in, I am holding it quite firmly both to the table and to the fence.

    The saw table has a hump, even with the arbor, running right to left. When I run a dial indicator pointed down and contacting the table, I get a variation of -.006 from the first teeth to midway between the center and the rear teeth. Photo is a reinactment, was actually measured tighter to the blade.



    The indicator reads a -.016 from front to back over the entire blade when run along the right miter slot.



    And here is what the burn looks like. Please forgive the picture quality, as these are just to illustrate that which is difficult to state clearly verbally.



    By the back of the cut, there is a clear ridge or indentation along the burn line that is close to .006 deep, as measured with a feeler gauge.

    Now, for the last confounding variable. I had forgotten all about this actually, but when I first got the saw, I had noticed the hump, and took the top off and brought it to the dealer to show them. I was told it was no big deal, that they all had variations, and that it was within mfg. tolerance. When I went to reassemble it, I noticed that the top didn't make contact at all four corners of the cabinet, and placed a washer between the cab and the top in the right far corner (standing at operator's position). This evened out the contact points.

    Tonight after measuring as in the second photo, I removed said washer from between the cab and the top, remeasured, and it cut the variance in half, from -.016 to -.008. But is also gave me a hump on the right side similar to that on the left, as it essentially bent the table down when the bolt was tightened. I made another cut, and it didn't seem to make any difference in the burning, so I put it back in.

    That got me wondering if the hump on the left side could be corrected by placing a whasher there? Actually, the ends of the table front and rear on each side slope down a bit in relation to a known steel straight edge. I guess I'll experiment some with that when and if I ever get to finish my current project.

    And now, the rest of the story...I was able to get a nice clean cut using the miter fence on the right side of the blade, rather than using the sliding table, so I guess that's what I'll use for now, untill I can get the rest of this figured out.

    I would be happy to hear any other thoughts anyone might have about this situation.

    Dan
    "A dog teaches a boy fidelity, perseverance, and to turn around three times before lying down."
    Robert Benchley

  8. #8
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    It turns out the table was not level with the blade. This weekend I shimmed in the back with 1/16" washers on right and left, now it's within .002 over the length of the blade, and there is no more burning. I left the front two bolts tight in place, and raised up the table with a car jack enough to insert the washers one corner at a time. I was surprised that I the first try did the trick, and that I didn't need to realign the table to the miter slots.

    Dan
    "A dog teaches a boy fidelity, perseverance, and to turn around three times before lying down."
    Robert Benchley

  9. #9
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    Forgive me of being critical of you. I believe you made a mistake in not getting (justifiably) irate with the folks you bought it from. They made a phony excuse about them all being like that. What you have is supposed to be a quality product with an inexcusable defect. If it is still under warranty, I believe you should take it back and demand they make good with either repair or replacement.

  10. #10
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    Dan,

    I'm in a similar boat, but I have to agree with Frank. This is the kind of thing that drives me nuts. One example: on my ridgid 3650 the miter slots are out of parallel with each other... substantially. It's so bad, one doesn't even need sophisticated measuring devices... just mark a piece of wood, slide it from front to back, and you can see they're out of line. This means I have to choose which slot to align the blade from, and if I use the other I get the kind of burning you were getting. Only difference: I *knew* I was buying a cheap table saw, so it's just something I've accepted. If I spent a fortune (what you have is *way* out of my universe), and had to deal with something like that, I'd be hopping mad. Course, I'd still make a similar time calculation to yours (can I be down for weeks while I wait for a replacement, or can I get back up and running today with a jury rig), but it would bug me all the same...

    Thanks,

    Bill
    Last edited by Bill Lantry; 02-27-2007 at 03:33 PM.

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