Tablesaw Burning with Crosscut Sled

[Steve Nekias]

I have been building some kitchen cabinets of late. I have a 10" Delta Unisaw and I've never had burning with a combination blade. I purchased a 80 tooth Oldham Industrial Carbide finishing blade for this project. I also built a large crosscut sled. As usual, I set my blade depth so that 3 - 4 teeth are protruding through the top of the material being cut.

Problem. Cutting through 3/4 inch melamin-surfaced particle board there is a little bit of burning evident on the material. When I start using the crosscut sled, the burning is *very* noticable. After cutting a batch of panels the air is very acrid and smokey.

The blade is square to the fence. The blade is sharp. The blade is clean. I've experimented with faster/ slower feed rates, with not much success. The sled is true and produces very lovely, perfectly square panels -- just nicely toasted on the edges.

Any ideas?

Mr Fixit eh

[Leon]

RAISE your blade a bit more. 1/2 to 1 tooth higher than you have it now.

[John]

Time to check the miter slots to blade alinement. Sure sounds like the blade is NOT really parallel to the miter slot that the sled is riding in

John

[Leon]

I thought that also at first but he did indicat that the sled is true. Seems that trouble started with the new blade. A blade with a 80 teeth has tooth contact for a greater time than one with 40 teeth. IMHO he needs to raise the blade to cut down on the time that the teeth are in contact with the material that is being cut.

[Ba r r y]

Raise the blade.

Barry

[good ol' Bob]

Leon, John could still be right in his assessment. The sled may be true because the 90 degree fence (backstop or whatever his sled uses) is true to the miter slot, but the blade isn't. Picture a blade that is off by 15 degrees. If the sled is square to the miter slot, you will still get a square panel. I wouldn't want to be the operator in such a setup 'cause there will be much burning and weird loud noises and such. If the blade is not aligned to the miter slot, but the fence is, you would have no problem when using the rip fence. (We're talking much less than the fifteen degrees mentioned in the extreme example above.) When setting up a table saw, you must FIRST align the blade to the miter slot THEN align the fence to the blade.

[John]

Check the blade for TRUE then, maybe a warped blade if the miter slot is parallel to the blade.

John

[Leon]

Yeah I know perhaps I should have also included that he said "and produces very lovely" cuts. If the sled were tracking into the side of the blade, there would probably also have tooth marks on the pieces.

[Steve Nekias]

Thanks very much, guys. I will be cutting more panels on the weekend. I will raise the blade. If that doesn't work, I will double/ triple check the alignment of blade. I'll post back with any success.

Steve

[Steve Nekias]

I cut another series of panels today.

Raised the blade so that 6-8 teeth (80T blade) are above the stock surface. This did reduce the burning, but did not eliminate it completely. There was significant chipping of the melamine surface of the particle board.

I re-checked the alignment of the blade to the miter slot. With a straightedge aligned with the blade (between teeth front and back), the measurement between straightedge and miterslot is 1/16th closer to the miterslot at the back edge of the saw table than at the front edge of the table.

Is this enough out-of-alignment to cause burning?

The reason there is not burning when using the fence is that the fence must be out-of-alignment with the miter slot by the same amount that the blade is out?

Thanks for your help.

Mr Fixit eh

[Mike Marlow]

Yes. Get yourself a cheap dial indicator and do a google search for table saw set ups in this group. Tons of information on it. Get your blade within .005" and you'll see a HUGE difference. You can probably get it within .001" if you really want to go that far - and many of us do, but within .005 should be fine.

[George]

Or use your combination square, referencing to the miter groove, using the ruler as a touch gage. If you are curious how far out is out, use cheap feeler gages.

Should be same tooth - touch and touch fore and aft.

[Mike Marlow]

Yup. Funny how sometimes we get so used to doing things the way we do and then overlook other, sometimes more simple or less expensive ways. It's because I'm lazy - and maybe getting lazier the older I get, that I recommend the dial indicator. It saves me having to mess around with my feeler gauges to determine the error as I go back and forth. But, like I've said about a lot of other things here, woodworkers have been doing a lot of things in a lot of different ways for decades and in some cases, for centuries, so my way sure as hell ain't the only way.