Replies

1. 
   ring | Apr 30, 2005 10:22am | #1

   I can't honestly say that I perceive differences in the quality of cut when ripping solid stock.  It somewhat affects how tightly the wood is held down to the table by the action of the blade, but even this is not usually critical.

   Crosscutting I can sometimes (depends on a lot of factors) get less tearout when the blade is high above the surface.

   Cutting sheet goods I use the scoring blade anyway and the height of the main blade doesn't seem to matter much to the results.

   DR

   (I use a  SCM sliding tablesaw with 14" blade)  

2. 
   Peter36 | Apr 30, 2005 10:34am | #2

   I set my blade at different heights for different reasons. If I am cutting something fairly thick I will raise the blade all the way because then there are less teeth engaged in the wood and less resistance. If I want my smoothest cut I keep the blade low so there are more teeth involved for the cut. If I am cutting something very narrow or very close to the fence I will only raise the blade about a 1/64" above the wood to minimize any chance of cutting myself.                 Peter

3. 
   DJK | Apr 30, 2005 04:02pm | #3

   Blade tooth geometry makes the difference. With a flat top rip blade I have the tooth tip just above the material because the tooth cuts like a chisel. With a high ATB the tooth tip is about 3/4 of the tip height above the material, more of a slicing action. Each blade type has a different requirement.

   DJK

4. 
   woodensplinter | May 01, 2005 12:01am | #4

   Generally speaking, I raise the blade so the bottom of the gullet is at approximately top of the wood.  After that, I may tweak the hight, depending on the results I'm getting.

   Interesting topic.  Wonder if FWW will do a test with various types of blades?

   Over the years, I've read different theories regarding blade height and they range from setting the blade to maximum height for all cuts to having the tooth just protrude through the top surface of the wood.  When push comes to shove, I haven't seen anything conclusive.

5. 
   StewartL | May 01, 2005 12:14am | #5

   FWW has addressed this as I recall in one of their old articles. None the less Kelly Mehler the table saw guru addresses this in his book and video on the table saw. When asked how high to raise the blade he responds, "How much of your hand are you willing to lose?" He raises the blade just above the wood being cut. I have heard a lot of arguments but I find them all trumped by safety. I have heard the argument of the bottom of the gullet should be above the workpiece. Some blades eg hollow ground planer blades are designed to be raised a certain amount above the work piece. With all others I simply follow the safest course of action as outlined by Kelly.

6. 
   WillGeorge | May 01, 2005 04:02pm | #6

   I have never studied it but I'm am SURE blade height somehow can make a difference on tear-out on sheet stock..

   But then again just me...

1. 
   silver77 | May 01, 2005 05:46pm | #7

   I insist my students maintain 1/8" only above the stock as a margin of safety in case they are ever stupid enough to get in there. Sometimes when cutting melamine, we have to go a bit higher to get a cleaner cut.

   I have a new lx1000 that cuts melamine clean as a whistle on both sides and to get a good cut I have to run it with 1/2" of the blade showing...not perfect but it works.

   I shudder to think of the time a foreman had me raise a dull planer blade as high as it would go to cut an opening in an arborite cabinet door. I should have said NO but I was young, stupid and lucky.

   I do believe in guardian angels!

   short answer...always keep the blade as low above the stock as possible.

   FWIW, I am attaching table saw rules that my students must learn like the ten commandments.

   cheers,

   silver    

   
1. 
   WillGeorge | May 01, 2005 05:49pm | #8

   but I was young, stupid and lucky..

   Dang it WAS FUN then!

   My most fun shop was Metal Working..

   The teacher had lost a hand on Wood Table Saw... He was so funny... but REALLY SERIOUS on shop safety!

   I even made a dish about 20 inches in diameter from copper.. He drew the outlines (I can't draw a stick man).. I carved a bit on his outlines..

   I go it .. BEST IN SHOP!

    

    

   Edited 5/1/2005 10:56 am ET by Will George

   Edited 5/1/2005 10:57 am ET by Will George

1. 
   GRW | May 01, 2005 05:58pm | #9

   Will,

   I was taught to have the blade 1/8" to 1/4" above the work. This was for safety and to maximize blade tooth contact with the wood, which in turn allowed the saw to cut easier and reduce binding.

2. 
   silver77 | May 01, 2005 06:11pm | #10

   Bet ya still have that dish...it's what you keep your change in ??

   or did you give it to your Mom??

   All's well that ends well...

   I too was inspired by a shop teacher...like to say I started on this path in night school and have gone full circle-teaching night school now...among other things-call myself a carpentry and woodworking entrepreneur-sounds good...

   Sunday morning...just chatting before I go for a bike ride and head into the shop for the rest of the day.

   cheers man,

   silver 

2. 
   forestgirl | May 01, 2005 07:57pm | #11

   Thanks for posting your rules, silver.  I found that they fit with what I do already, though a couple of things I could be more consistent.  My hubby's showing signs of wanted to fool with the tools, so I'm gonna print those out and post them.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the  "I Rocked With ToolDoc Club" .... :>) 

1. 
   silver77 | May 02, 2005 01:42am | #12

   glad they were of use to someone,forest girl

   Safety is constant vigilance...I have found the rules work to help keep students safe...12 years and no accidents...knock on wood...

   best regards,

   silver

3. 
   DonC | May 02, 2005 07:23am | #13

   If you are teaching, your advice is good. (Liability too)

     If you are in your own shop cutting cherry or other easy to burn species, I raise the blade as high as it will go. I do this because when I was at a woodworking show, I was watching a Forrest blade guy doing his demonstration. I asked him if he could cut cherry without any burn marks. He raised the blade up to it's highest, ripped half way thru a board and let it come to a stop with the blade spining. He then finished the cut and there were no burn marks. The reason is there is no friction. Only one or two teeth are buried in the stock at any time. I bought the Forrest blade and dado. Best buy I ever made.

1. 
   silver77 | May 02, 2005 08:30am | #14

   I don't know man...I use a Freud thin kerf rip 1/8" above cherry-no burns and no saw marks-and if I did get burns, I would prefer to run them over the jointer than run a blade at full height-no margin of safety IMHO.

     silver

4. 
   JohnSprung | May 03, 2005 04:03am | #16

   Good rules, but I haven't heard the term "fast lane" applied to a table saw before.  "Control the fast lane" isn't quite clear.

    

   -- J.S.

    

1. 
   silver77 | May 03, 2005 08:14am | #17

   Thank you for that John.

   I try to IMPRESS my students that the lane between the blade and the fence is the fast lane

   and you stay out of it's way and control it because the blade is turning at 100 miles an hour

   and if you don't control it or stand out of it's way the stock is headed into your nuts at 100

   miles an hour.

   Control the fast lane is shorthand but maybe I need to work on it??

   silver 

1. 
   JohnSprung | May 04, 2005 01:15am | #18

   > Control the fast lane is shorthand but maybe I need to work on it??

   It depends on the context in which you use these rules.  If your students all get 100% right on a pop quiz asking the definitions of "control" and "fast lane", then it's fine the way it is.  If you want a generic standalone set of rules that you can hand to anybody in the woodworking world, then it needs to be stated with the expanded explanations. 

   I guessed right about what you meant by "fast lane", but if the workpiece is still in one piece and it kicks back, it's the whole thing that's heading your way.  

   Another important consideration is, the smaller the workpiece, the bigger the danger.  Both from having your hands near the blade, and from kickback.  A big heavy piece may get thrown like a medicine ball, but a small one kicks back like a bullet.  It's an impedance matching kind of thing, the blade transfers a lot more energy to pieces close to its own weight.

   The other question is the meaning of "control".  There has to be more to it than just having your hand on a piece of wood, pushing it towards the blade.  Especially if the machine has enough power to kick back harder than your hand can overcome.

   There's a more general "control" safety issue involved any time you're using muscle power to push or pull on something.  If that something suddenly slips or breaks loose -- like when hauling on a wrench breaks a nut loose -- the muscle power you're applying is suddenly without resistance, and whatever body parts you were pushing or pulling with move very rapidly in the same direction they were going slowly before.  In the specific case of hand moving towards blade, that can be bad news. 

   One last table saw rule that my father used to insist on is to lower the blade all the way when you're done with the machine. 

    

   -- J.S.

    

    

2. 
   silver77 | May 04, 2005 07:32am | #19

   Thanks for the food for thought, John Sprung...always trying to improve my style.

   silver 

3. 
   81treehouse | May 10, 2005 05:32am | #20

   Thanks to all that posted on this thread.  I think that there is quite a variance of opinions.  The retyped answer from Freud gives an interesting response as many think the more teeth, the better.  The Forrest story is also quite interesting.  Surprisingly, if I understand, they contradict each other somewhat.  Anyway, that is what this forum is about -- woodworking.  Thanks again for everyone's posts.

    

    A bad day woodworking is better than a good day working -- yes, I'm retired!

7. 
   woodensplinter | May 03, 2005 12:42am | #15

   I thought I'd pose your question to Freud.  I also asked about kickback potential and anti-kickback blade design.  They responded (within a day I might add) with the following:

   The correct height to run Freud blades is approximately 1/2 to a full tooth (tooth, being just the carbide part and not the gullet for the tooth) higher than the material being cut however, everyone should read, fully understand, and follow all the recommendations that are contained in the instruction manual for the machine and any accessories they are operating.  If the one  of the manuals for the machine or accessory recommends a blade height lower than this, then that blade height should be followed.  If you are using the correct blade with the correct number of teeth for the thickness of the material you are cutting then this will give you the best cut quality.  The reason some woodworker's think they get a better cut by running the blade higher or lower than this is because they are using a blade with the incorrect number of teeth for the material they are cutting.  Additionally, running a blade with more of the blade exposed out of the cut than this is a safety hazard as well.

   As for the issue of kickbacks, they are caused for a number of different reasons and are very dangerous.  There is no one device or group of devices that will eliminate kickbacks.  This is why Freud always instructs everyone to read and follow the instruction manuals for the equipment and any accessories they are using.  As for the blades Freud adopted a safety standard originally developed by the German DIN organization.  The theory behind this design is that by limiting the maximum amount of bite each tooth takes, the effects from kickbacks, due to overfeeding, can be reduced.  The standard also has limits based on tooth spacing where the limiters are required.  So a blade with a high tooth count, 60 teeth and over on a 10" blade, does not require the limiter because the teeth are so close together.  On Freud saw baldes that require limiters, we place a limiter before each tooth to limit the maximum amount of material that can be removed to 1.1 mm.

   Sort of long but I wanted an opinion from the horse's mouth.  I figured blade manufactures should have a better explanation than I could ever have.

   I tried to copy Freud's response as closely as I could.  Typos are probably mine (sorry).

   All I can say is THANKS to Freud for thier quick and excellent response.  Told them I would share their response on this forum.

   For help in selecting the right blade for the job, go to the following lik on Freud's web site:  http://www.freudtools.com/tool_search.mp?question=question1&section=a