Grumpy: TS Still Burning

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Thought I had the problem licked, but I ran through a bunch of panels last night and I'm still getting some burned edges cutting 1/2 inch melamine particleboard with the crosscut sled.
The degree of burning is alot better than it was BEFORE I adjusted the blade alignment, so it's not fill-the-whole-house-with-eye-burning-smoke burning. There are just very visible burn marks along most of the cut edge, on the cut-side of the workpiece. There is some chipout as well.
I have adjusted the blade carefully with a dial indicator to within .0005"--assuming it is accurate. I checked it again several times. I reference the gullet of one tooth, zero-out the indicator, then carefully rotate the blade and check the measurement at the same reference point but at the back of the saw. I am careful not to introduce side-to-side pressure on the blade.
The dial indicator is screwed to a wood stip which is clamped to the miter bar. There is no sideways 'play' in the miter slot. The dial indicator is referencing the blade at a 90 degree angle. The dial indicator is newly purchased from Lee Valley.
The blade is a new Oldham 100 tooth blade marked, "Ultra Finishing Plywood/ OSB Industrial Carbide." The blade is only a month old, with maybe 2-3 hours cutting time on it. There are no chips in the blade, and it has just been cleaned.
I checked the runnout on the blade, and it is showing out-of-round by .002 inch showing on the dial indicator. I am not able to check the runnout on the saw's arbor because I don't have a magnetic base for the indicator, but there is no play in the arbor.
I'v run cuts without the crosscut sled and there is no signs of burning. With the crosscut sled--burn marks. I tried raising the blade up, but that does not help improve the burning. It did result in worse chipout, however.
Any ideas about what to do?
Mr Fixit eh
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Snip

When you cut WITH the cross cut sled are you feeding the wood from the same side of the blade as when NOT using the cross cut sled? Some times miter slots are not parallel. Does your sled use the same miter slot that you used to tune the TS?
I tried raising the

More chip out sounds normal especially if the path runs towards the blade. If there is less or no chip from the other side of the blade your saw could still not be tweaked enough or the blade is not good, new or not.

Try another blade. If the burning is less I would suspect the blade. Try cutting from the other side of the blade. If the burning is less your TS is still probably not set up properly.

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...and are you sure the sled is precisely aligned? If the marks are always on the same side you may not have an exact 90-degree angle on the sled.
Bob
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That would manifest itself as out-of-square cuts, not as burning.
-- Regards, Doug Miller (alphageek-at-milmac-dot-com)
Get a copy of my NEW AND IMPROVED TrollFilter for NewsProxy/Nfilter by sending email to autoresponder at filterinfo-at-milmac-dot-com You must use your REAL email address to get a response.
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Wouldn't matter.

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You didn't mention how the panel is being held in the cross-cut sled. I suspect the panel is moving slightly on you and that is why you're still seeing a slight burning.
When I built my sled, I built-in a sliding cross-piece that goes from front to back. In that I used two clamp screws like used on the Delta tennon jig. They were modified slightly by brazing some large washers on that hold the clamps in the cross-piece and allow them to slide for positioning.
When I place a panel in the sled, I position the clamps so one is at the front of the panel and one at the back edge -and both are near the line of cut. Place a piece of thin scrap under each clamp so they don't get indented and screw both clamps down - the panel doesn't move one bit.
You can probably use a temporary jig to see if that is the problem and clamp the panel down so it cannot move in any direction. Worth a shot to see if that's a good fix - or not for you.
Bob S.

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Leon The sled uses both miter slots.
The chipout is on the upward-facing surface. The surface that rests on the sled is purrrfect n pretty.
I don't get burning when I use my 40 tooth combination blade, but I figure it's because the 40 tooth blade is just more forgiving.
Bob, I like the idea of the clamps, I will try to add clamps to the sled at some point. I'm pretty sure that the burning is not from panel movement on the sled because the burning is so consistent, but I could be wrong. I will try to jury-rig some clamps to see if I can rule it out one way or the other.
How much runout can a blade have before it would cause burning?
Mr Fixit eh
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wrote:

sounds like it's the back (upward moving) teeth doing the damage.
is the <fence> part of your sled good and straight? if it's bowed, either way, it'll tend to bind up the material.

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Then I suspect that you sled is not tracking parallel to the blade. The back side of the blade is cutting again. Only the front side of the blade should be doing the cutting.

Or better suited. I use a 40 tooth WWII for "Everything" I threw my 100+ tooth blades away after using the Forrest.

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Hard to believe the sled is not tracking to the blade considering the sled is tracking to the miter slot (via miter bar), and he said the blade is parallel to the miter slot
John
On Thu, 03 Feb 2005 19:59:59 GMT, "Leon"

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Yes that would be hard to believe but if the back of the blade is hitting the wood the sled would not be tracking correctly and most likely because the slots are not aligned properly to the blade. Or he is letting the wood slip.
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Leon The sled uses both miter slots.
The chipout is on the upward-facing surface. The surface that rests on the sled is purrrfect n pretty.
I don't get burning when I use my 40 tooth combination blade, but I figure it's because the 40 tooth blade is just more forgiving.
Bob, I like the idea of the clamps, I will try to add clamps to the sled at some point. I'm pretty sure that the burning is not from panel movement on the sled because the burning is so consistent, but I could be wrong. I will try to jury-rig some clamps to see if I can rule it out one way or the other.
How much runout can a blade have before it would cause burning?
Mr Fixit eh
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I'm not trying to slight anyone and this is far fetched but worth asking if everything else checks out:
Is the blade installed in the right direction? DAMHIKT.
Chuck
Mr Fixit eh wrote:

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If it burns with a sled, but not without, then something about the sled is not square; either the sled or the miter slots.
More teeth are more likely to burn; if you can try a 60 or 80 tooth blade...
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Just a thought: Clamp the dial indicator setup to your c/c jig and then check runout. Sam
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I like this idea. If you clamp your indicator to the fence on the sled, then slide the fence past the blade, you will be able to see if your fence is at a true 90 degrees. I suspect it is not.
snipped-for-privacy@aol.com wrote:

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msschm and Larry: I clamped the dial indicator to the crosscut sled about midway between the front and back fences. The blade is OUT OF ALIGNMENT with the sled by .008", How can this be, I ask when the blade is within .0005 to the left-hand miterslot?
So I check Leon's suggestion and test the alignment of the right side miter slot. Guess what, it's out by .011. There must have been enough slack in the left-hand slot that the crosscut sled is tracking mostly to the right-side miter slot.
Also, I was somewhat wrong in saying that there is burning on the sled but not when using the fence (without the sled). I had been checking the cut panels, not the offcut. Because the burning is on the offcut when using the fence, I wasn't noticing it when cutting using the fence -- I wasn't checking the offcuts. When using the fence, the burning is less than when using the sled, but still noticeable.
SSSOOOOOOO.....
I guess I'll need to double check the fence alignment.
And now my question becomes, Ok, how do I correct for the misaligned miter slots to overcome this problem. O yeah, once I fix this miter slot, how can I re-align my crosscut sled .
Growl.
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Is this a new saw? If so see if the manufacturer will get yo a new TS top and begin the alignment fun again.

I do not think you can other than using the slot that is actually parallel to the blade and do not use the other slot. Remove the sled runner that fits in the slot that is not parallel.
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wrote:

That is what I have been doing for years ...out of laziness I must admit..
Bob Griffiths
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If you just bought a cabinet saw, I'd call them to get a new top. I don't know acceptable tolerances for miter slots on new tops, but I doubt the slots on even a PM66's are within .0005. Maybe I'm wrong.
I suggest adjusting the trunnions to average the slots out. FYI .0005+.011/2=.00575 But that's because I prefer to use a dual slot cc jig as I expect single slots jigs would deflect. Once again, maybe I'm wrong.
My $.02 less capital gains =$.016 Sam
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