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Thread: Sawstop Injury I didn't think this could happen.

  1. #226
    Quote Originally Posted by andy bessette View Post
    Running the blade too low can cause the workpiece to rise.
    Of course. The question is "what is too low?"

  2. #227
    Quote Originally Posted by Carlos Alvarez View Post
    Huh, and I've always heard that the blade tips should just barely clear the wood, and the cleanest cuts come from doing that. My experience is that my saw sounds better also, and often, noise equates to wasted energy/force, which often also leads to undesirable loads. I don't think I've ever heard someone advocate something different.
    it is very common to have the blade high in the UK. I do believe that the idea of it low blade is to reduce the exposed blade should the hand come in contact the injury is less severe . A crown guard take care of a high blade and finger contact and the riving knife keeps the rising teeth at the back from lifting the work in the high possession . in the low possession the blade want to lift the work at the blade and then slap the wood around on the table,at least if your at the end of a long stick and are not putting down pressure at the blade. also high count teeth blades with small gullet do not have a chance to clear at the top and so can pack before they go out the bottom, this can bind the blade up on the sides with packed saw dust and pull on the work or burn . the only time i rip(cross cut is different ) with the blade low is if i have a cross cut blade in the saw with little set and i do not want black eyes on the plate . mind you i am to lazy to change out for the right rip blade for just one cut LOL. i like the blade high for ripping in general
    jack
    English machines

  3. #228
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    Like most of life, I think there are different schools of thought about blade height, just as there are about short vs long rip fences. The high blade cutting downward, the nose guard, and the short fence are the English way - and maybe the Euro way- Jack will know better than I. I do prefer the higher blade and short fence on my 16-18" saws but I also pull the fence forward to add more support in front of the blade for longer stock. I don't know if the methods for a 10" blade would necessarily be the same as what works with a 16" blade which also cuts a much wider kerf. I have about 10 saws and each has slightly different sweet spots. When I rehab a saw, in addition to the splitter or riving knife, I spend a fair amount of time aligning the rip fence and eliminating the runout on the arbor. I feel both are essential. A good riving knife on a saw where the fence or arbor move under load is still a poor design. Dave

  4. #229
    Quote Originally Posted by David Kumm View Post
    Like most of life, I think there are different schools of thought about blade height, just as there are about short vs long rip fences. The high blade cutting downward, the nose guard, and the short fence are the English way - and maybe the Euro way- Jack will know better than I. I do prefer the higher blade and short fence on my 16-18" saws but I also pull the fence forward to add more support in front of the blade for longer stock. I don't know if the methods for a 10" blade would necessarily be the same as what works with a 16" blade which also cuts a much wider kerf. I have about 10 saws and each has slightly different sweet spots. When I rehab a saw, in addition to the splitter or riving knife, I spend a fair amount of time aligning the rip fence and eliminating the runout on the arbor. I feel both are essential. A good riving knife on a saw where the fence or arbor move under load is still a poor design. Dave

    Not a matter of theory the short fence and high blade at all Dave . A matter of fact which is relatively easy to demonstrate with badly stressed timber on an under powered saw if you want to be brave. To my knowledge the short rip fence technique has been taught in colleges in the UK (and for that matter most of Europe) as general practice since at least the 1960s and appeared as the "norm" on purpose-built saws from the earliest days ( 1840s). The fact is the long through fence was introduced on lower cost general purpose saws in the 1930s possibly as a means of handling sheet materials and NOT solid timber. The fact that it was a cheaper alternative to a properly triangulated rip fence mounted on a substantial fence bar probably encouraged it's propagation, but look at any medium to heavy weight industrial saw ( Wadkin AGS or Startrite powermatic Delta Saw Stop are by definition both low cost and lightweight designs). I find it interesting that in the 1970s Wadkin finally gave the AGS a decently triangulated rip fence and that the last of the Startrites were similarly equipped with a modern sliding face rip fence.

    Incidentally I use neither and both - my saw has a sliding fence plate which allows it to be used as a short rip fence (also useful as a lengthening stop when crosscutting) as well as a long fence (useful, for example, when ripping thin solid timber edgings which can require extra support). This has been the norm on professional quality European saws for many years as opposed to DIY or amateur equipment. Most of the time the fence is used in short mode as it is possible to experience kickback even when one is ripping MDF against a long fence, especially if the board is warped or "case hardened" , also that for professional workshops the use of the short rip fence has been mandated on safety grounds since at least the 1974 WW Machinery Regs


    for those that do not know what type of fence we are taking about here is one (after market) . Delta used to make one .

    d2d0_1.jpg

    for those wishing to learn more on the TS fence for the DIY look here


    http://fence.morecheap.us/how-to-bui...ble-saw-fence/
    Last edited by jack forsberg; 07-20-2018 at 4:38 PM.
    jack
    English machines

  5. #230
    Perhaps this deserves its own thread.

    My one major kickback happened with a high blade and extended fence. Anecdotal, of course, but just sharing. I've never had a kick or any issue of any sort once I got my saw tuned to perfection, then re-did it for even more perfection. Since then, everything is smooth and safe. And I always run with the blade *barely* peeking over the wood.

  6. #231
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    I'm not sure I see the benefit of a short rip fence because, assuming the fence is properly adjusted parallel or slightly open to the blade I dont see it contributing to kickback. None the less, it would be simple to add a short fence adapter board to a standard fence if anyone sees the need.

  7. #232
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    Quote Originally Posted by Carlos Alvarez View Post
    Huh, and I've always heard that the blade tips should just barely clear the wood, and the cleanest cuts come from doing that. My experience is that my saw sounds better also, and often, noise equates to wasted energy/force, which often also leads to undesirable loads. I don't think I've ever heard someone advocate something different.
    Set your saw so the teeth just come thought the top surface of the cut piece. Then with the saw off push a piece of wood into the blade, most likely it will climb right up over the blade. Now raise the blade an inch or more above the top surface and repeat the push test. You will have great difficulty getting the piece to climb up the blade.
    Lee Schierer
    USNA '71
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  8. #233
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    I also agree with the higher is better blade height. I think it presents a better cutting angle to drive the piece down during cutting, particularly rip cutting. A low blade height will present much more force pushing back on the piece toward the user. I think this contributes greatly to the kickback hazard.

  9. #234
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    I was taught to set the blade height so the bottom of the gullet was at the top of the material being cut. Is that now considered too high?
    If at first you don't succeed, redefine success!

  10. #235
    Quote Originally Posted by Lee Schierer View Post
    Set your saw so the teeth just come thought the top surface of the cut piece. Then with the saw off push a piece of wood into the blade, most likely it will climb right up over the blade. Now raise the blade an inch or more above the top surface and repeat the push test. You will have great difficulty getting the piece to climb up the blade.
    Well you got me, I went out and tried it. It's not difficult at all; rolled right up onto the blade in both cases. And there is zero correlation between a blade being moved slowly in the wrong direction compared to a blade moving at 5k RPM in the correct direction. You'd have to be moving wood at 100 MPH to make it really climb versus cut.

    Here are some thoughts on it that seem useful: https://www.protoolreviews.com/trade...-height/24594/

    Freud's position is that you want a full tooth to clear the wood and no more.

  11. #236
    Quote Originally Posted by Ben Rivel View Post
    I was taught to set the blade height so the bottom of the gullet was at the top of the material being cut. ?
    Been doing this since Day 1 as I was told a low blade would be less conducive to under the table dust collection.

    Simon

  12. #237
    Quote Originally Posted by Pat Barry View Post
    I'm not sure I see the benefit of a short rip fence because, assuming the fence is properly adjusted parallel or slightly open to the blade I dont see it contributing to kickback. None the less, it would be simple to add a short fence adapter board to a standard fence if anyone sees the need.
    the real problem is with reaction timber in grades less than select or better. unless you can predict case Harding and which way a board will behave and will push off the fence into the blade and rising teeth at the back . the worst would be with a right tilt saw and the blade tipped into the fence . the short fence really does a great job here . you can just make out the inverted U-slots in the riving knife on the Hammer below (note crown guard removed for illustration purposes and fence plate not necessarily in the best place . the crown will not foul if the sliding plate is in the low position and pulled back to front of center on the blade
    HamerHiFence.jpg

    as to the riving knife most have no idea of the proper spec on these.

    HSERivingKnifeFixing.jpg

    HSERivingKnifeSection.jpg
    jack
    English machines

  13. #238
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    Quote Originally Posted by Carlos Alvarez View Post
    Well you got me, I went out and tried it. It's not difficult at all; rolled right up onto the blade in both cases. And there is zero correlation between a blade being moved slowly in the wrong direction compared to a blade moving at 5k RPM in the correct direction. You'd have to be moving wood at 100 MPH to make it really climb versus cut.

    Here are some thoughts on it that seem useful: https://www.protoolreviews.com/trade...-height/24594/

    Freud's position is that you want a full tooth to clear the wood and no more.
    Not all saw blades move at 5K rpm, many are considerably slower.
    Lee Schierer
    USNA '71
    Go Navy!

    My advice, comments and suggestions are free, but it costs money to run the site. If you found something of value here please give a little something back by becoming a contributor! Please Contribute

  14. Quote Originally Posted by Lee Schierer View Post
    Set your saw so the teeth just come thought the top surface of the cut piece. Then with the saw off push a piece of wood into the blade, most likely it will climb right up over the blade. Now raise the blade an inch or more above the top surface and repeat the push test. You will have great difficulty getting the piece to climb up the blade.
    Lee I respect you a lot! This ithread can be learned from. Thank you for your more in depth contributions... as you are absolutely correct. Raising your blade while using riving knife and overhead guard help extremely,... feather boards and short fence help extremely when cutting reaction lumber. Sometimes using Long fence that extends beyond the blade after the cut, arc‘s into the blade causing a jam that the riving knife wasn’t designed for.

    This becomes an other danger. This is the danger that most woodworkers have not been trained for but is relevant if only ever using long fence. Most European sliders encompass short fence designs. Implementing a long fence is still there for ply material.

    What is The new company’s owner going to do with this technology?
    How is the service going to be for the next 20 years?
    Will PARTs be replaceable?

    Lee, what table saw you presently running? What would you really replace it with, considering the use to market?

    Do you have a dream table saw weather vintage or present day?

    My personal vintage would be complete pk. I am working on it.
    If I have the space, money, I would order a brand new Altendorf F 45.
    Last edited by Matt Mattingley; 07-21-2018 at 2:19 AM.

  15. #240
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    Quote Originally Posted by Matt Mattingley View Post
    Lee, what table saw you presently running? What would you really replace it with, considering the use to market?
    I currently own a 1-1/2 Hp Craftsman 113 model saw with the open web cast iron wings. I have added a 4 foot extension table out the back side of the saw, which allows me to handle long pieces of work without assistance. I have a Beismeyer fence and a Kreg cross cut guide. I use Grip-Tite feather boards and Freud full kerf blades. The saw suits my needs very well and I have no desire to replace it. Best of all it has paid for itself many times over.
    Lee Schierer
    USNA '71
    Go Navy!

    My advice, comments and suggestions are free, but it costs money to run the site. If you found something of value here please give a little something back by becoming a contributor! Please Contribute

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