Scoring question

[Marshall Harrison]

While I was in the middle of my table saw search I noticed that some of the sliding table saws and high end European saws had a scoring blade. So I am wondering why we don't see more of this and if any of you guys make a scoring cut on plywood and laminated face material before making the actual cut.

It looks like it would be easy to make a pass at a lower blade level to score the surface then make the final pass with the blade at the correct height.

Or is a scoring blade more of a gimmick than something practical.

[Matt Day]

It’s practical with melamine. Lots of cabinets are made out of melamine and commercial shops use panel saws with a scoring blade.

[Ed Mazuronis]

While I was in the middle of my table saw search I noticed that some of the sliding table saws and high end European saws had a scoring blade. So I am wondering why we don't see more of this and if any of you guys make a scoring cut on plywood and laminated face material before making the actual cut.

It looks like it would be easy to make a pass at a lower blade level to score the surface then make the final pass with the blade at the correct height.

Or is a scoring blade more of a gimmick than something practical.

Scoring blades run in the opposite direction of the main blade. That way the tooth makes the cut on the way into the material instead of on the way out. Without a sliding table, it would be very hard to get an accurate scoring cut because of the tolerances involved. Typically the scoring blade is shimmed ~0.1-0.2mm wider than the main blade to compensate for the wobble.

[Peter Kelly]

The scoring blade should be exactly the same width and position as the main one. Any width variations would have the potential to cause issues with edgeband adhesion.

[Rod Sheridan]

Scoring blades certainly aren't a gimmick, I use mine for all veneered and laminated panels.

The scoring blade is just a tiny amount wider than the main blade, a few thousandths of an inch, just enough so that the main blade doesn't chip out the lower surface.

regards, Rod.

[Jim Becker]

In addition to the obvious of using my scoring blade for sheet goods, I also occasionally use it with solid stock that's proving to be "ornery" with how the main blade is leaving it on the bottom.

[Al Launier]

If the fence is set up to cut the panel, why not turn the blade backwards for the scoring cut, then install it correctly for the actual cut. Does a 0.001"-0.002" really make a difference?

I've used my saw blade backwards in the past when cutting plastics.

[Mike Chalmers]

If the fence is set up to cut the panel, why not turn the blade backwards for the scoring cut, then install it correctly for the actual cut. Does a 0.001"-0.002" really make a difference?

I've used my saw blade backwards in the past when cutting plastics.Don't think this would gain anything. Blade is still making the cut in the same direction, whereas the scoring blade is traveling in the opposite direction. This would just result in a cut trying to be made with the wrong side of the blade teeth. That can't be good.

[Peter Kelly]

If you've got a good sharp blade, a scoring pass with the blade projecting up 1/4" or so into the workpiece will prevent chipping/splintering. Raise the blade up to full height on the second pass to complete. Anywhere from 60 to 80 tooth ATB or TCG will work fine.

Please do not put a blade in backwards on a table saw. Small diameter scoring saws turn counter-clockwise, opposite direction of the main blade for a chip-free climb cut.

[Jamie Buxton]

I regularly do the scoring trick when I’m cross-cutting plywood with my conventional tablesaw. I make the first pass with the blade barely exposed, and a second pass to cut the full thickness. Works like a champ. It does require some way to ensure the two passes track. I mostly use my crosscut sled. The rip fence also can do the job.

[Grant Wilkinson]

I just know that I'm going to get blasted for this, but I run melamine through my table saw backwards with the blade exposed just enough to score the thin melamine. Then, I raise the blade and cut it normally. With the blade exposed so little, the blade does not pull the sheet away and I get chip-free cuts.

[Mike Kreinhop]

The scoring blade should be exactly the same width and position as the main one. Any width variations would have the potential to cause issues with edgeband adhesion.

The scoring blade on my MM SC2 is about 3.2mm wide and is adjustable in height as well as lateral movement. This allows the scoring to accommodate different main blade thicknesses and allow a clean scoring cut for slider or fence cuts.

[Jim Becker]

Mike, I got an adjustable width scoring blade with my S315WS, but prefer the dead-on 1/8" wide one I got as an alternative that perfectly matches my main blade width. I like having that adjustable one in the cabinet "just in case"!

[David Kumm]

If no scoring is available, a HI AT blade is made to not chip the bottom if the stock is held flat to the table. They dull fairly quickly and are not to be used for much else but veneer panels. Not as efficient but works. A sliding saw for panels should have a scoring blade. Dave

[Peter Kelly]

Just to clarify–either split or conical style scoring blades should be positioned to the exact width and alignment of the main blade.

Matched panel sizing blade sets are usually only found on beam saws.

[Chris Parks]

My slider hasn't got a scoring blade, I just lower the blade as others have said, score the cut in the normal direction and then the final cut. No chipping which works for me.

[Scott Buehler]

My sliding table saw is set so the scoring blade is just slightly wider than the main blade. It works great on ALL panel goods and I wouldn't cut them without it. I recently purchased an older Delta rt31 with scoring blade but have not had the chance to use it yet because I'm searching for a blade flange that is no longer made for it.

[Wayne Lomman]

I just know that I'm going to get blasted for this, but I run melamine through my table saw backwards with the blade exposed just enough to score the thin melamine. Then, I raise the blade and cut it normally. With the blade exposed so little, the blade does not pull the sheet away and I get chip-free cuts.
Yep, I'll oblige! DON'T DO THIS. You will be happy doing this until one day you forget that the blade is a bit dull and it all goes horribly wrong. A sriber cut is a climb cut but it is with a tiny saw blade attached to a low powered motor. Even so, a dull one can focus the mind wonderfully.

And to others, please don't install your blade backwards. It is called backwards because it is incorrect.

That aside, if you don't have a scriber, use a good quality triple-chip blade and a steady feed rate and your break out will be almost invisible. Commercially, a scriber saw is essential. Time cannot be wasted on elaborate techniques, multiple cuts etc. I was actually unaware you could still buy a slider without the scriber. I haven't seen one without it since 1990 and that was an old machine then. Cheers

[andy bessette]

...a scoring pass with the blade projecting up 1/4" or so into the workpiece will prevent chipping/splintering...

I do this, but only raise the blade 1/16"-1/8" for the scoring cut. Prevents splintering on expensive veneered ply.

[Peter Kelly]

If you've got repeat cuts to make, you can also raise the blade just over half the thickness of the workpiece, flipping over the the part to cut both sides this way e.g. 5/8" blade height for 3/4" material.

[Jim Becker]

If you've got repeat cuts to make, you can also raise the blade just over half the thickness of the workpiece, flipping over the the part to cut both sides this way e.g. 5/8" blade height for 3/4" material.

You'd still want a ZCI for this because any tear out on the bottom is because of the blade exiting the material in a downward motion and that extra support will help with the edges to some degree. But I'm not able to visualize how a non-through cut is going to help with the real problem here as the blade exiting isn't any different than with a through cut.

[Jamie Buxton]

.. But I'm not able to visualize how a non-through cut is going to help with the real problem here as the blade exiting isn't any different than with a through cut.

When I do my first pass, the blade is just above the table surface -- maybe a tenth of an inch or less. The blade tip is running almost tangent to the bottom of the piece of plywood. It is not exiting down, but rather exiting almost horizontally. I think that's key. Consider just a single wood fiber as it is being cut. In a full-depth cut, the fiber is being severed with a downward motion, and there's little to prevent it from breaking downward -- that is, chipping out. However, in a skimming cut, that fiber is being pushed against the wood fibers next to it along the wood surface. Those not-yet-cut fibers support the fiber which is being cut, and prevent it from blowing out.

[Jim Becker]

Jamie, that makes sense, but the comment I was responding to has the first cut at half the thickness which is a little different animal relative to how the blade is behaving. In your example, and with a good ATB blade angle, you're scoring the edges. I still wouldn't give up my scoring blade, but what you describe is a good alternative when one isn't available if the time to do the extra passes is there.