High or low blade to avoid kickback on table saw? Manual vs expert carpenter
I am a complete newb with table saws (just opened my first one today) and was reading the manual. It says to prevent kickback to have the blade just above wood height. This made sense, but then so does this: http://www.waterfront-woods.com/Articles/Tablesaw/tablesaw.htm The guy says to have a high blade to prevent kickback. What is the general consensus really? — On a second question, I’ve laminated together some thin bits of wood to make a fat one and now I am trimming off their edges so that I end up with a squared block. These are to be two foot high table legs. I am ripping them against the fence with barely trimming enough to have anything but saw dust on the other side. I am going to use the safety shield and pawl doohickey but for something like this I see a guy on expert-village freehanding it. Should I use the push stick, though? I am still reading up on safety but not sure at what point I “know enough”. Trying not to be too intimidated by it. I am fine with a miter saw but this seems more dangerous.
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You are wise to treat a tablesaw with respect. I had a minor accident with a too small piece of maple - lost a fingernail, and had that panic moment of "Oh @&%$! Oh %#@*! 1 - 2 - 3 - 4 - 5, 1 - 2 - 3 - 4 - 5, Phew!"
What brand and model of TS do you have? There are some new features that are coming out to make their use a little safer.
For what you are doing with that trimming, you should look at making a sled.
http://www.highlandwoodworking.com/aslidingtableforyourtablesaw.aspx
http://www.rd.com/18191/article18191.html
I made mine with a 2'x 4' piece of plywood, with a couple of boards on the long edges sitting vertical. A clamp on the vertical boards keeps the pieces secure as they cut.
As far as blade height, I like the blade low so I can keep my push stick close to the cutting edge when I push though.
I don't know what kind of saw
I don't know what kind of saw that you have, but I have a bosch portable. It really depends on what I am cutting, I tend to keep the blade high enough where the carbide on the tooth just clears the material, or where the bottom of the gullet clears the material. Unless I need to make a cut where I am trying to utilize the most vertical portion of the blade. However the more blade exposed equals a greater risk of an accident.
You may ask what difference the type of saw makes? For me the quality of the saw is directly related to the safety of the saw. Most very small portable saws in the 100 to 150 dollar range, utilize a fence that does not self align very well or at all. Parralelness of the blade to the fence is critical to prevent binding and kickback. The more ridgid the fence is when locked also means that you can put more pressure on the fence for certain cuts and feel safe that it wont move thus putting the blade in a bind.
The number one safety tip I have is use a push stick or push blocks, featherboards etc. to keep your hands a safe distance from the blade. Second is to study the manual, or find and learn proper technique. Third, have adequate material support on the left side of the blade if cutting something large, and at the outfeed end of the blade. my outfield support also doubles as my work table. Fourthly, this is a peeve of mine, and the number one thing I often see inexperienced users doing. Do not crosscut a long narrow piece, ie. a 14" 1x6 with the 6 inch end against the fence. Use a mitre gauge or a wider sled for this type cut. If the 1x6 rocks at all in the cut it will bind the blade and can kick back.
I think the rational for the advice to keep the blade high comes from the idea that the higher the blade the more downforce on the workpiece against the table, which is not incorrect. IMHO if a saw is properly setup, to limit binding whether from a misaligned fence, or from stresses in teh wood being cut itself, you can leave the blade as low as long as it is cutting adequately and will properly eject sawdust and chips. But I agree with the author of the link. I think it does depend on the power of the saw and what you are cutting. It will not hurt to leave the blade higher especially of you are using the gaurd. it also is a little bit of an experience thing. You will get it, just think thru each setup, and cut before you make it and never work rushed or tired.
Sorry for the long post, Be safe.
On your second question, you dont say how wide the glue up you are ripping is, but my advice is to use a pushstick because you will need it to push the stock thru with the gaurd setup in place not to mention that it is safer.
You might try some basic cuts on some good size scrap wood to get familiear with the feel of the saw, since its new.
My thought would be that high meant less chance of kickback.
A lower blade means that the teeth in the wood are moving more or less traight back towards the user.
If the blade is higher, the ones in front are moving downwards a bit more, which might help push the wood against the table rather than back at you.
But as someone else already pointed out, the more teeth are exposed the more dangerous it is because of that.
I think a splitter or riving knife is your best protection against kickback. It keeps the wood away from the blade after you've pushed it through.
Kick back has some fine reasons for happening! Blunt, dirty, wrong blade for job, poor alinement of the fence.
But more teeth exposed means a "deeper" cut can be made and thats the last thing you need if you have a problem!
Pushsticks and featherboards are highly recommended.
I try to stand to the left side of the piece I am ripping so that if it does kickback (it has happened) the piece doesn't hit me. The ONLY time I am behind a piece is when it is too wide to feed from the side, typically sheet goods.
As mentioned by an earlier poster- support your outfeed properly. If you are feeding to another person it can be tricky you don't want them to pull untill the cut is almost complete (maybe not even then).
If you have an appropriate top you can get a magnetic type featherboard which are fast to set up and hence more likely to be actually used.
I almost always use a guard which covers the entire blade. Amongst other benefits I know that as long as I don't stick anything under the guard I won't come into contact with the blade.
Be especially cautious when working with small pieces. They are often the most unstable and dangerous to work with.
It is worth repeating USE PUSHSTICK(S). I try to keep a couple on my fence so I don't get halfway through a rip to discover none are within reach.
As to blade height vis a vis kickback I dunno. I usually set up so the gullet just clears the material. A higher blade may sometimes produce a smoother cut.
Work safe! Asking questions is a great start. It is the uninformed and the overly casual who are most likely to be injured.
Another problem with a high blade - you increase the chance of tearout on the bottom side of your cut.
Lots of good comments already. My preference has been the bottom of the gullet blade height, which I think is a reasomable compromise. I also use a push stick whenever the workpiece is less than about 6 inches wide, but you can decide on your own tolerance. I also stand to one side to avoid being impaled should the kickback happen.
One other perspective regarding high vs low blade position with regard to kickback.
If you are ripping a particularly unstable piece of wood it may have a tendency to want to warp as it is being cut. In some instances both halves will warp toward each other, causing it to "squeeze" the blade.
If this occurs and the blade is set significantly higher than the height of the wood, it will have a greater tendency to grab the wood on the "upstroke" and throw it back at you.
There is no such thing as too much caution when using a table saw.. Especially if you are inexperienced.
I have the small bosch first generation saw, and have had that instance happen to me. I followed Gary katz instructions on his website to turn the factory gaurd into a riving knife. It means butchering the gaurd, but the riving kknife functions well, and I wasn't using the gaurd anyway.
Skoorb:
Having dadoed my left index finger tip off and nicking my middle and ring, thirty years ago (Dec. 5, 1979), I consider myself a bit of an expert on tablesaw safety.
Unlike most things in life, tablesaws are non-negotiable. If you break their rules, you will get a possible life sentence immediately and unapologetically. This is not your wife or girlfriend or the cop who's pulled you over. I cannot overempahsize this. Tablesaws are deaf to your pleas for a second chance.
Use a push stick in close, but I like to keep my palm on the fence while I push with my right index finger and thumb. As long as you feel that fence, you know where your fingers are.
While most watch the blade, kickbacks happen when you let the piece drift from the fence. Pay atteniton here. If you're about 5'9" tall, a kickbacked piece will hit you right above Mr. Happy when it leaves the saw bed. You will double over in pain, but hey, while you're down there, hit the "off" button. Everyone in the shop has heard the sound of a kickbacked piece and is staring at you as you force yourself to stand and act like nothing's wrong. That red spot will turn purple and yellow in a few days. The outside edge of a sawblade is traveling at about 200 m.p.h. and it feels like that piece is going just as fast as it impales your groin.
To answer your question, I like my saw tooth gullets clearing the piece and no more.
Kowboy
It's very simple
Never raise
It's very simple
Never raise the gullets higher then you want to be cut. If the blade is 2 inches above the wood then the risk of a 2" cut id higher then if you only had it raised 1/4".
Second when you stop being afraid of your table saw its time to take up fishing or golf
I like your philosophy regarding being afraid of the saw ...
Sort of like my cat.. He's afraid of everyone and everything, but by golly nothing's ever snuck up on him...
I've had five saws in thirty years, or so. Two of them Unisaws, both a right and, the current one, a left tilt. I also have a Bosch [with the gravity rise] for job site work.
I still have all my fingers. Thumbs too. Part of that is because of my back trouble - I have a yellow streak up it, which causes me to use push blocks (not sticks) religiously. They are highly expendable and I have expended more than a few.
There as been some very good advice here. I assure you, the best is, make sure your fence is parallel to your blade. Setting it parallel to the miter slots wont work, if your blade isn't first set parallel to them (I just had to reset the Bosh).
The reason this is so important is you don't want your wood pinching THE BACK OF THE BLADE (emphasis, not yelling). Having the front of the blade slaming down against the wood does nothing significant to holding the wood in place. Pinch in back will, however, pick the wood off the table and throw it at, or through you.
For these reasons, the questions about your fence quality are more than a little valid. If your fence can move, or doesn't set parallel, the games will begin.
You can reduce the chance of kickback signifciantly with a splitter. They help keep the wood from pinching the back of the blade (nothing is fool proof-so do play the role). If you hate your factory splitter, spend the not insignificant amount it costs and buy an after market splitter. It's one of the best investments I ever made. It really does make a difference.
Ideally, you would have a riving knife, rather than a mere splitter. They are now standard on saws -for good reason. The go up and down with the blade, so you don't have to remove them for dados and other specialty cuts.
I like to keep the angle of the blade as it enters the top of the workpiece at about 30 degrees if possible, best compormise to me of exposed blade safety, tearout, and avoidance of kickback (sin 30 = 0.5, means as much downward as kickback force, good compromise)
NOW ripping with a RAS is a different matter <G>
BTW, first thumb interaction with table saw was 49 years ago, have shot pieces of trim thru my hand from kickback since*, but never gotten fingers on a running blade since then (either TS or RAS - chain saws another story ! )
*Never stand or have your hand in line with the blade.
I found it incredibly helpful to learn how to tune up my tablesaw. Tearing the thing apart, lubing it properly, aligning the blade and fence all add up to a greater awareness of how the machine can be in harmony. A good working knowledge of your saw means you'll be aware of its quirks and you'll be more likely to sense things are 'off' before something catastrophic happens. This, of course, doesn't take the place for paying attention while you're using the tool.. but I found that it adds a dimension simply because the saw is no longer a mystery to me.