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Plywood jams my table saw??

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Forum topic by Lt_scout posted 12-30-2016 07:02 AM 863 views 0 times favorited 15 replies Add to Favorites Watch
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Lt_scout

32 posts in 404 days


12-30-2016 07:02 AM

Hi guys,

I’ve got a Ridgid R4513 contractor saw, running a Freud 90 tooth blade.

Every time I run any kind of plywood through this machine it binds up on me. It seems the riving knife is the issue, like it’s too thick and jams up the cut. Or the blade is too thin?

The fence is parallel to the blade and the riving knife is aligned with the saw blade.

I’m not sure what I’m missing, unless this saw isn’t really intended to use premium thinner blades being a contractor saw.

Any thoughts? put Vaseline on the riving knife? =P

thanks!

-- When you know you can do more with less, you will require less to do more.


15 replies so far

View Holbs's profile

Holbs

1721 posts in 1863 days


#1 posted 12-30-2016 08:18 AM

Try having blade parallel to the miter slot. Fence parallel to the miter slot. Riving knife the same. With a dial indicator, check from front of blade, back of blade, front of riving knife, back of riving knife all in one sweep to see if anything is out of whack. That’s good for tune up viability.
As for riving knife or splitters, I believe there are 2 thicknesses: full kerf and think kerf. If I have a thin kerfed saw blade, it will bind on a full kerf riving knife. With dial indicator, check the thickness of the blade teeth against the thickness of the riving knife.
Other than that…hmm….wax your table top for there might be something causing too much friction? And same for the fence material?

-- The Carpenter Bee is derived from the Ancient Greek word wood-cutter

View Woodbum's profile

Woodbum

798 posts in 2899 days


#2 posted 12-30-2016 11:57 AM

Maybe you should try and use a blade with less teeth and more set that cuts just a slightly wider kerf. Try the 60 tooth Freud Industrial Ultimate plywood blade? Measure the blade with a dial caliper and the riving knife too. The riving knife can’t be thicker than the blade kerf width. I don’t think Vaseline on the riving knife is a viable option. IF…you were going to use a lubricant (but not necessary) use Bostic Blade Coat or another “dry slide” type of spray lube made for metal on woodworking and industrial tools. Good Luck, Work Safely and Have Fun!

-- "Now I'm just another old guy wearing funny clothes"

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knotscott

7784 posts in 3209 days


#3 posted 12-30-2016 01:22 PM

For clarity, your R4513 is a portable jobsite saw, not a contractor saw. It’s critical that the riving knife be thinner than the total kerf of the blade. I see 3 choices….get a wider blade, make your riving knife thinner, or remove it altogether.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

View bondogaposis's profile

bondogaposis

4475 posts in 2185 days


#4 posted 12-30-2016 01:38 PM

Are you using a full kerf riving knife w/ a thin kerf blade?

-- Bondo Gaposis

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gailmo

24 posts in 872 days


#5 posted 12-30-2016 04:52 PM

I have this exact saw and have had zero problems running all kinds of plywood through it. As other have said, check your blade thickness and your riving knife thickness. I am wondering if you bought a thin kerf blade? I think I would pull off the kerf knife and run some plywood through it. If it still sticks, then your blade isn’t running square to your fence. If it runs through with no binding, then you need to replace your blade with a regular thickness one. There are numerous posts on this site that discuss thin kerf vs regular kerf blades.

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Smirak

38 posts in 352 days


#6 posted 12-30-2016 06:08 PM

Thin kerf blade vs full kerf riving knife is most likely the issue as others have stated. I cut plywood perfectly fine on my 4513. I use a Freud 50t combination blade.

View Lt_scout's profile

Lt_scout

32 posts in 404 days


#7 posted 12-30-2016 06:44 PM

OK, you guys have given me something to think about here, many thanks! I didn’t know that there was such thing as a thin kerf riving knife. I bet Ridgid doesnt make one for this saw, I’ll look.

So based on what you guys are saying, I think I’m going to need a thicker blade, This 90 tooth Freud blade is thinner, it measures 2.24mm with the riving knife coming in at 2.34mm.

This .10mm thickness difference is the problem I think, I think I’ll have to remove the knife when cutting plywood.

Knotscott says this is a portable jobsite saw not a contractor saw, whatever it is I kind of regret buying it. I’m really enjoying woodworking and it seems really limiting for in terms of cutting larger sheets etc. I bought it for its fold up capability but now see its downfall. I think I’m going to upgrade to a proper cabinet saw or hybrid this year.

-- When you know you can do more with less, you will require less to do more.

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Carloz

954 posts in 425 days


#8 posted 12-30-2016 06:51 PM



...It s critical that the riving knife be thinner than the total kerf of the blade. I see 3 choices….get a wider blade, make your riving knife thinner, or remove it altogether.
- knotscott

Kidding, right ?

View Lt_scout's profile

Lt_scout

32 posts in 404 days


#9 posted 12-30-2016 06:57 PM


...It s critical that the riving knife be thinner than the total kerf of the blade. I see 3 choices….get a wider blade, make your riving knife thinner, or remove it altogether.
- knotscott

Kidding, right ?

- Carloz

So Removing the Riving knife is bad yes? from what I understand that thing prevents kickback. But I’m not all that concerned with kickback on a 4×8 sheet of plywood. With hands and face clear of the blade on this lower powered motor, the risk is seems very limited… but I’m new to table saws so I’m open to thoughts on removing the knife.

-- When you know you can do more with less, you will require less to do more.

View MrUnix's profile (online now)

MrUnix

5978 posts in 2032 days


#10 posted 12-30-2016 07:05 PM

Nothing wrong with removing the riving knife as long as you are careful. And for breaking down large sheet goods, even those with larger cabinet saws generally prefer to break it down using other means, such as a circular saw with a guide or a track saw, to rough size – then cutting to final size on the table saw. And any time you are working with larger pieces, always provide aux. support (roller stands, outfeed table, etc…).

Cheers,
Brad

PS: Keep in mind that riving knives were not available on most saws made prior to 2009.

-- Brad in FL - In Dog I trust... everything else is questionable

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Lt_scout

32 posts in 404 days


#11 posted 12-30-2016 07:16 PM



Nothing wrong with removing the riving knife as long as you are careful. And for breaking down large sheet goods, even those with larger cabinet saws prefer to break it down using other means, such as a circular saw with a guide or a track saw, to rough size – then cutting to final size on the table saw. And any time you are working with larger pieces, always provide aux. support (roller stands, outfeed table, etc…).

PS: Keep in mind that riving knives were not available on most saws made prior to 2009.

- MrUnix

OK… interesting, thanks Brad, makes sense

-- When you know you can do more with less, you will require less to do more.

View ThistleDown's profile

ThistleDown

44 posts in 551 days


#12 posted 12-30-2016 07:56 PM

I just got a Grizzly saw and they do not make a thin kerf knife for it. So I am going to take off a little using my belt sander until my thin kerf blade is 1/64 more than the knife. If you do this make sure you do it on both sides equally or you risk a bind on one side and slop on the other. Polish it up with the buffer wheel to keep it slippery.

If you ARE cutting sheet goods with this saw you should have a thick kerf blade anyway. I have found that a thin kerf will flex just a bit when stressing a 4×8 sheet into the blade. This only matters if you need an exact measurement, as making furniture, like with Baltic Birch. Hey, it happens.

My 2p.

-- My biggest fear is that when I am gone, my wife will sell my tools for what I told her I paid for them.

View gailmo's profile

gailmo

24 posts in 872 days


#13 posted 12-30-2016 10:11 PM

I WILL NEVER EVER NEVER EVER cut plywood without a riving knife. I was cutting a 24” x 48” piece of 1/4 plywood that kicked back. I thought I was dead! The corner of the plywood caught me in the chest – and as I grasped my chest in pain, I kept looking for the blood. No blood, but horrible contusions. It was nasty looking for about 4 months. A year later, I found a lump in my breast (female here!) and thought I had breast cancer. Nope, when they did a scan, the doctor came out and asked if I was in an automobile accident. She said my left chest area looked like it was peppered with small nodules of blood.

So, I am very careful and always use a riving knife. And like others have said—- I break down plywood with a circular saw. Much safer and not difficult to do.

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runswithscissors

2557 posts in 1859 days


#14 posted 12-30-2016 11:16 PM

It’s not hard to make your own thin kerf knife. 14 gauge steel is abut right. You can also cut up an old saw blade. The body of the blade will be thinner than the kerf, because the teeth always have set. Doesn’t need to be a carbide blade, of course. Any thrift store should have a box of old blades to select from.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

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Holbs

1721 posts in 1863 days


#15 posted 12-30-2016 11:32 PM

I ran my PM66 for months without a splitter or riving knife. I survived. Granted, it was all plywood cutting and not stressed hardwood. I used faceshields, GRRRrippers, stood to side of the blade, etc. Took all the precautions of the accidental kickback. The world does not end if there is a no splitter/riving knife. Just means you have to be aware and prepared.

-- The Carpenter Bee is derived from the Ancient Greek word wood-cutter

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