TS blade height

[OpaDC]

Just a simple question for a newbie. Is there a rule of thumb for TS blade height? I understand it for tenons and other non thru cuts, but for crosscutting or ripping, does it matter whether full height or not?

[Hoyden]

only if you want to keep all your fingers.

only raise the blade just enough to cut through the lumber your ripping or cross cutting.

That blade is dangerous. a slip could quickly remove all your fingers or a hand.

[LCHIEN]

the rule of thumb, and this is not just for safety, is to raise the blade just a bit more than the cut requires, like almost 1/2" or so. That is, the tips of blade should come about 1/2" over the top of the board.

[OpaDC]

Thank you for the advice. Didnt know if it was a technical angle of cut issue, safety issue or something else. Kind of figured the less sharp points aimed my way the better.

[LinuxRandal]

Also read your manufacturers recomendations. Forrest tends to say run it a little higher, for the gullets.

[SARGE..g-47]

I run mne to the bottom of the gullet is at at the top of the stock, Opa. I would run it even higher as it puts more teeth in the cut.. but there is the safety issue.

But even then.. when I cut 8/4 (2"" and thicker stock, I will run it a bit higher to keep things moving. There is a lot of resistance in hard-wood in those thicknesses and a little higher than normal blade helps counter them to a degree and pin the stock down on the table.

[RodKirby]

OK - here's one against all the recommendations.

I leave my WWII set as high as it will go - mostly to get the maximum I can for my x-cut sled. But (assuming thru cuts), I leave it that way for rip cuts!

I like the idea of the teeth getting as much "down" action as I can, into the work piece - very effective for cutting acrylic.

[Tom Hintz]

I also run my TS blades just high enough to expose most of the gulllet between the teeth. The blade manufacturers sometimes have a specific recommendation for thier blade design but they most often seem to be right around "gullet high".
There is a school of thought that running the blade at it fullest height reduces the chances of a kickback because the teeth at the front of the blade are closer to coming straight down on the wood. Unfortunately, the teeth at the rear are coming closer to straight up and that is where most kickbacks start in the first place. That and having way more blade to get hurt on makes this a no brainer for me. The only time my blade is at it's full height is when the stock is actually that thick or the saw is unplugged and I am changing the blade. In a fixture where the blade is covered, maybe if there is a good functional reason for the height.

[rcp612]

I may be wrong but, I set the bottom of the gullets just high enough to clear the board I'm cutting,,,,except when I feel uncomfortable about possible kick-back. Then I set it as high as it will go to maintain downward force on the wood. IMO that reduces the chance of kick-back.
I've had no problems yet.

[Ed62]

As you can probably tell, this is an age old question that always gets different replies. My personal preference is to have the tooth about 1/2" above the work.

Ed

[iceman61]

I typically set mine at just under the gullet. Just make sure your fence is parallel with your fence & the blade is perpendicular to your table.(as long as you aren't doing a bevel cut)

I set my circular saw depth up the same way, just a little more than the gullet protruding.

[niki]

I'm with Rod Kirby...I also use a "High blade"...

In my opinion, safety, has nothing to do with "low blade" or "high blade" unless...one is not using the blade guard or have very wrong "table saw technics" (like, pass your fingers very carefully 1/8" from the blade but be very cautious")...

To demonstrate to yourself the difference, rip an 1¼"~2" Oak or other hard wood.
First, set the blade to 1/2" above and rip...note the required push force and feed rate...
And now, set the blade to "full height" and rip again...

You will notice that with "high blade", the push force is lower and the feed rate is much faster and that means that you require less power from the motor and the blade is at it's best performance (less teeth are in contact - cooler blade, no deformation).

To realize the difference you can make an experiment with the hand saw...ones cut (rip) while the saw is at an angle of 45°~60° to the wood and than change the angle to 90° (perpendicular) to the wood and note which method is easier and faster...

Just another example, look at the Band saw, with a 1/2~1HP you can resaw 5"~10" thick boards without any problem...with the table saw, you'll need much stronger motors...

niki

[SARGE..g-47]

I mentioned "safety" in my post because I realize there are those that are going to run their TS's without any proper devices to aid in safety. I didn't want to open a can of worms for those people as if you do that you have already put yourself in some jeoprady before you start the cut.

But.. with that said, I don't think that raising the blade to full height is best in my case. If you have any run-out of significance, you are exposing more plate to the stick to create friction.. heat and allow resin build. I think their is a happy medium on height. And of course, there will be a ton of different theories as we all have one.

In lieu of running the blade to the top.. over years of much ripping I have found the right height that works best for me with various thicknesses. One that gets the right amount of teeth involved.. causes less resistance in feeding.. keeps burn eliminated and reduces the amount of resin clean-up time.

I think having the right blade with the proper amount of teeth.. hook and grind has more to do with a good cut than blade height. But.. a blade too low in thicker stock will fight you and slow down your feed. I don't see the higher blade as a true safety issue unless you have no gaurds in place. There is not much way I can get my hand anywhere near the blade with what I use regardless of the height of the blade.

Here are some pics I took this morning of before and after the cut on stock 3' long.. 2" thick that was feed through rather rapidly to demo saw-dust control on another forum I was ask about. On that 2" thick stock the blade is raised about 3/4" below the gullet to give the best cut. There was no resistance moving it through rapidly. My hands won't be near a cut as I never violate my "red line" and have gaurds in place all around and above. So.. safety is considered before the cut with a raised blade.

The blade is an Amana 20 T Euro rip.. 20 degree hook.. flat tooth grind. This is important as the blade is made to rip and there are enough gullets to remove waste after the sever. A lower blade height would slow down the cut. I find just the right spot to not expose more plate than I feel necessary as sometimes too high will create resistance with run-out. BTW.. the blade is actually about 1/8" inside that upper crown gaurd as I slotted it to allow the blade to be raised to the upper teeth ride inside and not exposed.

Again.. we will all form our own opinions. This is just mine formed from ripping a lot over the years.

Ya'll have a good day as it's time for me to quit yabbing and "go ripping"!

[niki]

Hi SARGE
Well, I did not think about blade (or arbor) run-out...maybe because I don't have such a problem

The subject of "blade height" came-up many many times in many forums and I think that, as you said, everybody finds his comfortable height from experience and because everyone is different (mentally and physically) usually, every one has his own method.

On other forum, there was a question about cutting narrow strips. Well you know the replies...stop on the left and resetting the fence or, fixed fence with push sticks or sled...but the guy admitted that he is afraid of the strip trapped between the blade and the fence...again, what is good for some people, is not good for others.

I think that the answer to the "correct blade height" will be...put it at the height that you feel good with it....woodworking is not an exact science like math or physics, the blade will cut at any set height, the question is only, if you feel safe, confident and relaxed with your operation...listen to the little voice in your head and if it tells you - it's not safe...it is not safe...

Enjoy your ripping

Regards
niki

[SARGE..g-47]

I hear ya Niki and couldn't agree more. I don't have any significant run-out either.. but some saws do. But... from experience with ripping and using an assortment of TS's, I find that all will have some as even detail machining cannot be exact.

But.. ripping a lot of 2" to 3" stock in hard-wood, there is going to be a certain amount of deflection regardless of how good the run-out is. When you see a resin line build just below the teeth around the perimeter of a blade, that is too be expected. But if you raise the blade higher for the cut as you, Rod, etc. do and you see a resin line much lower... that has to be either run-out.. deflection or a combination of both I expect.

The teeth form a keft wider than the plate.. In a perfect world the plate (main blade body for new guys) should not touch the stock. But it does and when you run the blade higher to get better efficiency you will eventually build a resin line well below the teeth themselves. Not as quickly as the line just below the teeth, but it will show unless you clean the blade very often.

This is evidence IMO, that something is touching as resin cannot travel through thin air and attach itself to the blade very easily. So... even though I have no scientific proof of that, I can only believe my eyes and what the cut is telling me.

I will add that those that run one blade that have 40 T and up and rip with it, if you just expose the teeth you are going to be around awhile ripping thick hard-wood. And you will probably end up with some burn as that configuration with ATB teeth.. that many teeth and little gullet to remove waste is not the "Holy Grail" when in a ripping operation. One blade might "do all", but it ain't going to do it as efficiently as having the right match-up for a given task.

Just my thoughts, which is just an old man rambling and will probably be forgotten in 20 minutes..