Grumpy: TS Still Burning

[Mr Fixit eh]

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

[Leon]

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.

[BobS]

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.

[Woodchuck34]

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:

[toller]

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...

[Mr Fixit eh]

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

[Mr Fixit eh]

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

[Bob Schmall]

...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

[msschmenk]

Just a thought: Clamp the dial indicator setup to your c/c jig and then check runout. Sam

[tiredofspam]

I thought about that answer... and I don't know how that could be... The blade would cut a new slot no matter what alignment.... The piece being cut would be out of square... but the sled should have no effect.

Now are you possibly moving too slowly trying to eliminate chipout/tearout... This could explain the burning. You must move at a reasonable rate... the blade not being in alignment will cause a certain amount of burn, but .002 is not going to burn noticeably...

Oldhams have not received high marks in tests.... Try a better blade if all else fails. WWII is a great general purpose blade. I believe Forrest sells a laminate blade. I think freud blades do much better than Oldham.....

toller wrote:

[bridger]

sounds like it's the back (upward moving) teeth doing the damage.

is the part of your sled good and straight? if it's bowed, either way, it'll tend to bind up the material.

[Leon]

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.

[max]

There are things you can do. First, the end of the fence (past the blade) should be 5 to 10 thousands further away from the blade than the front side. Second, the gullets on the blade are probably not deep enough to carry away the chips, Third, use a splitter. My splitter is a piece of brass plate the thickness of the kerf. The splitter is adjusted (by bending) to push the wood against the fence. I would also try a faster feed rate. max

[Mr Fixit eh]

Woodchuck: not offended, but yes the blade is installed with the teeth facing towards the front of the saw. What's DAMHIKT?

Brid...: the fence is perfectly straight and rigid.

Leon says, The sled is tracking parallel to the miter slot within

0=2E001. Are you thinking that the fence is not truly 90 degrees to the saw blade?

Leon says, I called Oldham customer service. They said that this blade is not specifically designed for cutting melamine. They have a specialty blade with 80 teeth and a negative 10 degree hook angle ATB tooth. She said to try cutting a plywood panel, and if it doesn't burn then it is just the blade is not compatible with this material. I asked if the .002 runout could cause the burning and she didn't know what the specs on the blade were.

Is it possible that 0.002 runout could cause burning?

Thanks very much for all your replies, much appreciated.

[Leon]

Is it possible that 0.002 runout could cause burning?

Not likely. One more question. Is this a carbide tooth blade that we are talking about? I know some plywood blades are plain steel and the clearance between the kerf and the side of the blade will cause burning. Sometimes the side of these blades near the middle is actually wider than the kerf.

Thanks very much for all your replies, much appreciated.

[Leon]

Sorry I see that it is indeed carbide.

[Dave Jackson]

I've had similiar problems at work with a similiar blade. I ended up putting the old blade back on and the problem disappeared. Hopefully it'll cure you problem too --dave

[John]

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

[Mark Howell]

What do you mean "cuts w/o the crosscut sled"? Were you ripping or crosscutting with a miter gauge?

Does your TS have alot of vibration and are you using a blade stiffener?

[Leon]

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.