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Thread: Ryoba tenon cut problems

  1. #1

    Ryoba tenon cut problems

    I recently purchased this Ryoba Nakaya Reiji off the auction site from a man in Japan. It cuts crosscut great. When I used it to cut the cheeks of a tenon it drifts on the far side of the cut, even after I cut down the line on the far side first.
    image.jpg
    This is my first Japanese saw and it is mostly likely user error.
    image.jpgimage.jpg
    As you can see its SYP, so from what I read this saw should be ok for what I'm using it for. Does anyone have any pointers or suggestions. I tried numerous times with the same results after making adjustments with my stance and the mechanics of my draw.
    Thanks in advance for your responses,
    Eric Smith

  2. #2
    Join Date
    Apr 2007
    Location
    Columbus, Ohio, USA
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    2,040
    I am very interested in responses...

    A question first... Do I understand correctly that if you make a crosscut the saw does NOT drift, only when you cut into the end grain for a tenon shoulder?

    When a western saw drifts, that usually means that the set is different on one side than another. I have seen this fixed using a few different methods (such as running a file along one side or using a vice with a few sheets of paper to bend some teeth back). This does not work with hardened teeth I am guessing. I think that Japanese saws usually have hardened teeth.

  3. #3
    What method do you use to saw? It the tip of the blade pointing down? When the blade is being pulled? https://i1.wp.com/granitemountainwoo...7/IMAG0855.jpg

  4. #4
    Andrew, I have not made very deep cross cuts yet, 3/4" is the deepest and the saw cuts very straight and clean.

    John, I have been starting my cut with the saw cutting across the end grain then working my way down the tenon with the piece of wood pointing away from me at an angle. So the saw is horizontal but the the wood is angled, if that make sense.

  5. #5
    Join Date
    Feb 2004
    Location
    Perth, Australia
    Posts
    4,489
    It cuts crosscut great. When I used it to cut the cheeks of a tenon it drifts on the far side of the cut, even after I cut down the line on the far side first.
    Hi Eric

    The saw is drifting with the grain. This cannot occur when sawing across the grain. So the question is 'why does it drift with the grain?'

    The likelihood is that the blade is twisting, and this is more likely to occur if you begin sawing on the far side .. where you first use the toe of the saw plate. The toe end of the plate has the greatest flex. If you keep sawing using the toe end of the saw, the absence of a saw back will place the plate at risk for twisting.

    The solution may be as simple as ensuring that the kerf is created with the heel of the saw, and that you keep that end buried as much as possible.

    Regards from Perth

    Derek
    Last edited by Derek Cohen; 01-04-2017 at 8:15 AM.

  6. #6
    The solution may be as simple as ensuring that the kerf is created with the heel of the saw, and that you keep that end buried as much as possible.

    Regards from Perth

    Derek[/QUOTE]

    Derek, That makes sense. I will give it a try this evening. I was assuming the kerf on the far side would guide the blade as it does with western saws. I am quite please with the speed these Japanese saws cut, both crosscut and ripping.
    Thanks, Eric

  7. #7
    Are you holding the handle with two hands?
    Bumbling forward into the unknown.

  8. #8
    Brian,
    The first cut I used one hand. So I switched to a two hand grip and had the same results.

  9. #9
    I suspect that saw needs a sharpening, something is likely off in the set.
    Bumbling forward into the unknown.

  10. #10
    Join Date
    Mar 2006
    Location
    Austin Texas
    Posts
    788
    Brian or anyone else with ryoba experience: Any comment on one vs two hands holding the saw?
    David

  11. #11
    Quote Originally Posted by Brian Holcombe View Post
    I suspect that saw needs a sharpening, something is likely off in the set.
    This saw was advertised as NOS but I guess the saw could still be off.

  12. #12
    Join Date
    Apr 2010
    Location
    Tokyo, Japan
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    1,101
    Quote Originally Posted by Eric R. Smith View Post
    This saw was advertised as NOS but I guess the saw could still be off.
    Eric:

    A question. Your post did not make it clear that you were using the crosscut edge for crosscutting, and the rip edge for cutting tenon cheeks. Please clarify.

    The pic suggests the blade aggressively dived into the wood. Clearly, the SYP's strong grain was a factor, and perhaps poor/unbalanced set contributed, but it looks like pilot error. This happens to all of us from time to time.

    I suggest you try a number of things:

    1. Lightly grip the saw handle. My fencing master (not barbed wire fencing) described it as holding a bird in the hand hard enough so it can't escape, but lightly enough so it won't feel pressure.
    2. Put the index finger of both hands along the handle's side pointed towards the blade.
    3. Imagine the blade is a perfectly straight line, like a tensioned but delicate thread, resting in the kerf, passing through the blade, up through the tang, and out the butt of the handle. There are no lateral forces acting on this thin thread. Imagine it extending between your hands, and finally touching a specific point on your chest or side (depending on whether your grip is one or two handed). Memorize this point and envision the thread. With each and every stroke, the sawblade should precisely follow this thread, back and forward. The thread passing through the sawblade, tang and handle is very small.The point on your chest is very small. Aim small miss small.
    4. Don't force the saw or try to hurry the cut, or consciously apply downward pressure. The saw wants to cut because it is sharp, not because you are strong or fast or clever or handsome like Brian. Get out of its way.
    5. Carefully monitor the progress of the cut, stopping frequently to examine the kerf. Don't be lazy or impatient while you figure out your sawing habits. If it wanders even a little, STOP and figure out why that instant.
    6. Use an oilpot to lubricate the blade frequently. This will help it resist the temptations of contrary grain.

    There are several levels of saw sharpening in Japan traditionally. This does not apply to the kaeba saws (replaceable blade saws). Most saw blacksmiths are not up to the level of professional saw sharpeners. When they finish a saw, they give a quick & dirty "blacksmith's sharpening" which looks good, and will suffice for most folks, but often lacks great precision. Sometimes the set is not right. I have had this happen before with new saws, and the result was like a drunk trying to follow a straight line.

    New top-quality saws will often have a label attached which says 本目立て(honmetate) meaning "professionally sharpened." This indicates (but does not guarantee) that the saw was given a professional-grade sharpening rather than the usual blacksmith sharpening. This will add $15 or $20 to the cost.

    A professional saw sharpener (metateshi), or top-level saw blacksmith like Takijiro, has the skill and patience to do a much better job. They will often even do a better job of truing the plate than blacksmith will. This is more important than you might think. Plate truing is something that needs to be done with every sharpening. Indeed, it needs doing even if a saw sits around unused for several years due to the internal stresses intentionally applied to a quality sawblade working themselves out over time with unpredictable results.

    Takijiro told me his master made him spend the first two years of his apprenticeship doing only sharpening and plate truing. But this is not typical training. My point is that it is often wisest to plan on sending a quality saw off to be tuned and sharpened by a professional metatishi sooner rather than latter. The improvement in accuracy is almost always significant.

    With few exceptions, when I buy a new saw, the first thing I do is send it off to a metateshi for sharpening and truing.

    David asked about the two-handed grip.

    I prefer kataba saws (single-blade) for most situations, and although I have lots of huge, big, and medium-sized ryoba, I seldom use them anymore. However, I do prefer to use a small ryoba for installations in the field where I need to make short, shallow cuts precisely, and don't want to lug around two saws or spend time switching between rip and crosscut.

    Big and medium saws have aggressive teeth and make rough cuts. The kerf is wide, and plates are thick and stiff and tend to wander less. Speed is usually more important than precision when using these beasties. To develop power, the left hand is usually in front of the right hand so the two can leverage against each other to force the blade into the cut.

    When precision is paramount, try a different two-handed grip, with your hands placed directly and symmetrically opposite each other. Index fingers pointed down the handle, the sides of thumbs touching, and the other fingers more-or-less interlocking under the handle. With this grip, your posture and eyeball will tend to line itself up properly automatically. You will be able to sense when the saw is swinging out of the imaginary thread line mentioned above, which in this case, should penetrate the center of your sternum and come out your back. This method is not conducive to developing speed or power, but it is without doubt, the most precise grip. It does require that the workpiece be secured by clamp, foot, or butt vise, however.

    Stan
    Last edited by Stanley Covington; 01-09-2017 at 1:02 AM.
    『馬鹿に付ける薬はない』Toshiro Mifune in Tsubaki Sanjuro

  13. #13
    Quote Originally Posted by Eric R. Smith View Post
    Andrew, I have not made very deep cross cuts yet, 3/4" is the deepest and the saw cuts very straight and clean.

    John, I have been starting my cut with the saw cutting across the end grain then working my way down the tenon with the piece of wood pointing away from me at an angle. So the saw is horizontal but the the wood is angled, if that make sense.
    Eric.Is the stock clamped into a western vise mounted to the table? For japanese saw we cannot cut horizontal as there is no spine behind the blade. The blade will flex. To stop the flex the blade end must be pointing down.... Check this video. https://www.youtube.com/watch?v=nN7TD0hN6fI

    If all fails then grove the wood so there is a track on the wood for the blade to follow. It will act as a guide. The blade will follow the grove itself. Similar technique for western saws.

  14. #14
    Quote Originally Posted by David Eisenhauer View Post
    Brian or anyone else with ryoba experience: Any comment on one vs two hands holding the saw?
    I prefer to use two hands, the saw seems to stay on track better with two hands.
    Bumbling forward into the unknown.

  15. #15
    Quote Originally Posted by john zulu View Post
    Eric.Is the stock clamped into a western vise mounted to the table? For japanese saw we cannot cut horizontal as there is no spine behind the blade. The blade will flex. To stop the flex the blade end must be pointing down.... Check this video. https://www.youtube.com/watch?v=nN7TD0hN6fI

    If all fails then grove the wood so there is a track on the wood for the blade to follow. It will act as a guide. The blade will follow the grove itself. Similar technique for western saws.
    You mean like this;

    Bumbling forward into the unknown.

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