TS Blade burn

[Nick Lazz]

Hello all,

I have a Grizzly 691 TS, with riving knife. I spent an hour or so today re-aligning my saw because I was getting blade burn on rips with 6/4 and 8/4 stock. After I set it up with my saw gauge I was still having the same problem. I aligned the fence too and even added a little drift.
To try and fix the problem, I added even more drift to the fence(without measuring) and it did help but did not eliminate the problem.
I checked the entire length of the fence and noticed a slight (.003" - .004") bulge in the middle of fence so I swapped sides with my UHMW as the blade side was showing some signs of wear. This didn't fix the problem (and this is when I added more drift to the fence).

The blade is brand new and is a Freud Combo. It is not thin kerf, it is one from their professional series. Also, as big of a pain in the neck that the riving knife is on these saws, I adjusted that with the saw gauge too to do my best to ensure it was as close to directly behind the blade as possible without protruding either side.
I was ripping walnut and beach, both 8/4, and it was definitely more noticeable on the walnut. I'm wondering if: A) the bulge, as slight as it is, may be the problem or B) The combo blade is the problem with that thick of stock (although I was having the same problems with another blade).

Any ideas? Your help is appreciated.

Nick

[Victor Robinson]

Is the burning to the right (fence) or left (offcut) side of the blade?

What is your technique? (hand-feeding, push-stick, Grr-ripper?)

[Nick Lazz]

Right side burn. I usually hand feed but use push sticks when necessary. I have a grr-ripper, but don't use it on TS.

[Rod Sheridan]

8/4 is pretty thick for ripping with a combo blade.

Do you get the same results when using a rip blade?

Regards, Rod.

[Damon Stathatos]

Feed rate can be a factor.

[Prashun Patel]

Try ripping some 4/4 and see if you get burning. 8/4 is asking a lot from a combo blade. However, if the blade is new, on a cabinet saw, it should be able to do it fairly well.

What was the other blade you experienced burning with?

Have you tried a ripping blade? If yr going to be doing a good amt of 8/4, I'd get one. It'll save the life of your combo blade for doing what it does better.

[glenn bradley]

A combo blade is not a rip blade. You are getting the result I would expect. Walnut, cherry and other burn prone woods will yield better results with the proper blade. I have good success with a 24T blade to rip, 80T to crosscut and 40T for general roughing work. I do get good results on some woods with the 40T but if I am doing what I consider a 'final' cut, I use a task specific blade.

[Greg Wease]

You might try increasing the blade height so the tooth contact is more vertical.

[Howard Acheson]

Combo blades are generally optimized for 4/4 boards particularly when ripping. Because of the relatively high number of teeth, they do not clean out cut shavings as well as a dedicated blade intended for ripping. If the blade is sharp, you might be able to rip 5/4 stock but you may have problems with woods like cherry and maple which burn very easily.

The best advice is to use a 24 tooth rip blade for any boards over 4/4.

[Nick Lazz]

Thanks guys. I tried raising the blade before and it didn't work. I'm hoping the combo blade is the culprit, however the burn is not consistent. It is usually occuring about 2/3 of the way through the cut. The rest looks fine.

[Don Alexander]

2/3 of the way thru the cut would likely be right about the place you have to adjust your hands wouldn't it? sounds like you might be slowing down the feedrate at least slightly which could definitely cause some burns

[Brian Hinther]

Could the faster arbor speed (4300 rpm) of the 691 be a factor?

[Chip Lindley]

As others have mentioned, feed rate is probably the main factor in burning. A 50T blade will not allow fast enough feed in 8/4 stock to prevent burning. You need a real rip blade for thick stock.

I just ripped some 11/4 ash with a 30T Freud glueline rip. Perfect cuts with no burning. Of course, I jointed one board edge straight beforehand.

[Don Jarvie]

As you rip check to see if the board is moving off the fence as you get closer to the end of the cut. As I rip all goes well since I can push the wood aganist the fence with my left hand. Once I start getting towards the end of the cut I have to remove my hand and the wood creeps away from the fence.

I am thinking of a longer push stick so I can keep more pressure on the wood to hold it against the fence.

[Lee Schierer]

8/4 is pretty thick for ripping with a combo blade.

Do you get the same results when using a rip blade?

Regards, Rod.

Even though this is a 3 Hp saw, ripping 8/4 is pretty hard work. Nothing like a dedicated rip blade to make the cutting easier and burn free.

You don't say which Freud combo blade you have, but with regard to combo blades Frued says that the:

LU72 is recommended for rips up to 1" thick
LU71 is recommended for rips up to 1-1/4 thick
LU84 is recommended for rips up to 1" thick

The LM71 is recommended for rips in wood 1-1/2-3-1/2 thick
The LM72 is recommended from 3/4" to 2-3/4" thick, which would make it the ideal blade for your cut.

For smooth burn free rips get your fence flat and eliminate the toe out. I set my saw for zero toe out and get the blade as close to zero misalignment front and rear as I can get it to the left miter slot. If your kerf tends to open as you make the cut go to a short fence that ends near the back edge of the blade.

[Nick Lazz]

For smooth burn free rips get your fence flat and eliminate the toe out. I set my saw for zero toe out and get the blade as close to zero misalignment front and rear as I can get it to the left miter slot. If your kerf tends to open as you make the cut go to a short fence that ends near the back edge of the blade.

Thank you Lee, and everyone else who posted. I believe the blade is probably the culprit.

Tuning my saw has been a little frustrating. I read what you suggested and think I have probably already done it, but I'm not sure I know what zero toe out is.
Also, I'm not sure how to get the fence perfectly flat. The UHMW that is mounted on both sides of the stock fence, I swapped and both have the same reading and it is slightly curved toward the blade a few thousandths. I'm not sure if this is a concern, but if it is I don't know how to fix it, except by getting a new fence.
To deal with this problem I adjusted the fence starting where stock enters blade to where it exits blade, open about .005".

Thanks for all your help!