Ripping woes.... bad technique?

[Matthew Hills]

Advice above on chekcing alignment is my first thought, as well.

I'd also recommend checking cleanliness of your blade -- your cutting will suffer a lot if pitch builds up on the blade.

Matt

[Doug Garson]

You are correct, I was still misspeaking. Now corrected in original post. Sorry for the inconvenience.

Not a problem, I had a poster in my office decades ago which read "Although you think you understood what you thought you heard me say what you don't realize is that what I said was not what I meant" . We all do it sometimes.

[Steve Jenkins]

Are you pressing down really hard as you push the board through? Try dropping the blade below the table with the saw off and push the board through as if you were ripping it. It may be that your table needs to be cleaned and waxed

[Jim Dwight]

My PCS has the 1.75hp motor and I've had some ripping issues with it but only when I used a full kerf blade. You shouldn't need thin kerf blades with a 3hp motor. But you might need a ripping blade. I rip 3 inch softwood with a Freud Fusion thin kerf on my smaller motor saw, however (40 teeth). But it has to be well behaved without nasty grain warping the wood as you cut. I have also had ripping issues with a 1 inch oak board that was closing up the kerf due to internal stress despite the riving knife. A wedge into the kerf stopped that. I am using the stock riving knife with thin kerf blades but you have to get it spaced just right to do that and I think I need to make a small adjustment. Sometimes I have to push harder than I should have to because the riving knife is pushing the board against the fence. This isn't a terrible thing but I will move it out a little to stop that. It is not a hard adjustment and if you are using full kerf blades it isn't hard to position the significantly thinner riving knife within the saw blade kerf. SawStop offers a thinner riving knife too but you should only use it with a thin kerf blade.

I've cut more thick softwood than hardwood with my PCS but I ripped legs for my bed out of cherry glueups that were 3 inch thick. The saw went through it relatively easily. I am not sure which blade I used but it was probably a full kerf ripping blade. Today I would use a thin kerf ripping blade on my saw unless I decided to just try the Fusion that is normally on it. It does surprisingly well.

If your saw is setup properly I would look hard at the kerf closing up on you. That's internal stress in the board. You want to rip oversize and then recut because the board won't be straight after cutting either. If it is more than just one board or an occasional board causing issues then it definitely suggests a setup issue with the saw. If I can rip 3 inch hardwood with my 1.75 hp PCS (and I can and have and will again) then you should definitely be able to do it with 3hp. But warping boards can still be an issue.

[Augusto Orosco]

I tried without the RF or splitter, on 4/4 hard maple. It was much better than before, but still felt some vibration at the beginning. I have a video link here. https://youtu.be/aoaOD0aZRKQ

At the end, I got some burn marks on the left side of the blade (farthest from the fence). The burn marks are always worst on the left side. But this was way easier than before and it doesn’t really show the struggles I have described. I will try later with 8/4 soft maple to test again and will try to record it to better illustrate, but I am out of jointed material now!

I am using the WW-II on the video (40T, combo). The dewalt I found unopened is a general use 32T, so it’s not the 20T ripping I thought... I don’t even know why I bought it.

Any suggestions for a ripping blade to buy next?

[Andrew Seemann]

Is the edge of the maple against the featherboard rough? That may be giving you a lot of drag. If that WWII blade is clean and sharp, it isn't the problem. I have one on my 3HP Unisaw, and I almost never take it off. It will rip 3" stock just fine. Soft maple has a high sugar content, so a little burning isn't uncommon.

Also, going too slow on a rip cut with high sugar woods like maple, cherry, or even oak, can allow the wood and blade to heat up and start burning. One it starts burning, it tends to get worse since everything wants to expand a little, messing up your clearances.

If the edge was rough, the table a little oxidized or in need of wax, you might be going slow enough with the 8/4 that the heat isn't being carried away by the chips, and that could cause a fair amount of burning.

A video of the 8/4 would definitely help diagnose the problem. If you are out of 8/4, try ripping a 2" piece of that 4/4 down the middle to "simulate" 8/4.

[Mike Wilkins]

The wood could still have some moisture in it and the kerf is closing in on the riving knife. I have been using a dedicated ripping blade a lot lately making cutting boards with no problems. I too occasionally get some push back when ripping but I chalk it up to stress in the wood just releasing as it's cut.

[Michael W. Clark]

Make sure the table is waxed. Even if the saw is aligned correctly, friction on the table makes it hard to push.

[Brian Tymchak]

From the video you provided, I think I hear the saw bogging down towards the end of the cut. A 3hp saw should sail thru 4/4 without skipping a beat. Have you pulled the 2 belts on the saw lately and cleaned or replaced them? Where I volunteered (until Covid came along) we had a SS that started to bog down cutting 3/4" melamine first thing in the morning after the weather started to cool off in the Fall. After running for 15 minutes or so it would be fine. We found that the belts had picked up quite a bit of dust and the cool weather I think contributed to belt slip. I've since wondered if this indicated a problem with the dust collection.

If the belts are slipping, the feed rate has to slow down, which is going to build heat in the cut and burn the high sugar woods.

[Daniel Smith]

The wood could still have some moisture in it and the kerf is closing in on the riving knife. I have been using a dedicated ripping blade a lot lately making cutting boards with no problems. I too occasionally get some push back when ripping but I chalk it up to stress in the wood just releasing as it's cut.

I've had issues with maple moving and pinching that I haven't seen in other species. Since I trust my saw is set up correctly, when I get resistance pushing a piece through a rip cut, I start watching the kerf to see if it is closing down.

[ChrisA Edwards]

You asked for blade recommendations, I use a Forrest WWII Thin Kerf 20T rip blade on my 3HP SawStop.

I also bought a thin kerf riving knife from SawStop for use with this blade.

Ripping with this blade is night and day difference than my normal WWII 40T Combo blade.

[Prashun Patel]

Looking at your video, I wouldn't call that a problem. Feeding maple through fairly slowly will result in that much burning routinely for me. You may also have the featherboard set a little tight.

Given that your problem reduced drastically once the RK was removed, my money is now on the thickness of the splitter relative to your blade being the issue.

As for blades, I use Freud blades from AMZN 24 or 30t and they work fine. I've used cheap blades too. They may not last as long as expensive ones, but they cut fine for a hobbyist, IMHO.

You can try ripping a couple pieces without the featherboard in place to be sure it's not your alignment.

[Jim Dwight]

Burning maple in my experience is a feed rate issue. Too slow, it burns. But which side you burn it on is an indication of where the friction is that is cause you to have difficulty feeding. If the side of board between the fence and the blade burns, the fence is likely tilted very slightly towards the blade. That would cause a feed rate issue too. Since you indicate it is the offcut side, I would look for a fence tilted a little too much away from the blade. That should not cause a feed issue however. It is a little hard to measure precisely enough, at least for me, but I use a good steel ruler to measure the distance from a blade tooth to the fence at the front and the back with the blade raised all the way. Distance should be the same or very slightly greater at the back. You could also try using dial calipers on the inside measurement side. Or you could just adjust the fence a little and see if it helps.

Your observation of lower feed effort without the riving knife indicates you need to move it a little away from the fence. That could be your biggest issue.

The best ripping blades have flat top grind. I like 24 teeth but if you have one with 32 teeth that has flat topped teeth, it should rip better than an all around blade. I have never used a Forest blade so I don't know anything about it's resistance to feeding on a deep rip but different blades are different in the pressure required.

[Johnny Barr]

The only time I've ever had a problem like this on my SS was when the timber is warped, particularly if its convex shape looking at it from the fence like this ..... )!

[Augusto Orosco]

I wish I could tell you what made the difference, but I am really not sure. I checked alignments again, made sure the splitter was properly positioned and that the blade was properly sized for it. Adjusted the fence again to make sure it was mostly parallel with just 1/64” wider towards the back to avoid pinching. Made sure the belts were clean and the table was smooth and didn’t need any wax. Also eased up on the feather board just a bit. Milled another piece on the jointer from the same 8/4 soft maple board that gave me trouble before and tried again. This time no issues, not even burn marks. I shot a video thinking I would show how hard it was to push and instead I just got a smooth ride even with the combo blade. One thing that felt different, though, was that the board was going straight and smoothly through the path. On the previous tries (including the other video with the 4/4), it felt that it wanted to tilt away. Not this time... everything went rather smoothly.

Anyway, I still have a 20 tooth rip blade coming in the mail tomorrow. Never hurts to have one around. Thank you all for all the help walking me through potential issues. Considering everything and making sure everything was done well, including technique, really helped. If the problem comes back again I will go through that checklist to troubleshoot... and likely bother you again. But now, albeit a bit puzzled, am happy with the end result.

The video: https://youtu.be/eCqsUN1JSxo