Thread: Need Technique Tips for Ryoba Saw

Hi.

You didn't specify (other than front/back) whether your problem is with cross or rip cutting. I think typically, your symptoms occur most often when ripping (assuming there is nothing wrong with the set of the teeth) but can also happen with cross cutting. Although you may feel like you are not intentionally pressing the blade as you pull, you may be and this exerts enough pressure to influence the kerf under the board, causing it to wander off line. Another factor may be the actual direction of your pull. Again, you may not feel you are doing anything but pull straight back, but often your arm moves slightly laterally, especially near the end of the stroke where your arm and saw handle are closer to the body. In either case, it only takes a very slight amount of flex in the blade to make the teeth bite to the left or right in the kerf. Where you can see (the front or top of the board), you can correct to the line when you see it wander, but in doing so, again you exert pressure causing the blade to flex and the back/bottom will wander (in fact, moving the blade to correct often makes the problem worse). And once the blade starts to go awry, again because they are so flexible, continuing only makes things worse (the extra friction on one side will just continue to push the teeth in the opposite direction even if you try to correct).

So what to do?
First, when pulling, make sure you pull only exactly parallel to the axis of the saw, both laterally and vertically. Because J-saws are so thin and flexible (and they cut amazingly fast - so can make mistakes amazingly fast), any downward force on the teeth (where you try to push them down into the wood) will cause the blade to flex (you can see this if you just put the cutting edge on a flat surface and gently press down on the handle - watch how easily the blade flexes). You may not see any flexing as you are cutting, but if your kerf wanders, you will know there is something causing it.
Second, you may have to flip the board over every few strokes (still sawing into the same kerf, but from alternating sides). Despite your best efforts, if your line has wandered too much, you may have to start over at the opposite end (if applicable) and hope you don't get so far off on that try.
Third, leave extra waste allowance to compensate for your corrections (planing/paring to the line later).
Four, analyze your stroke as you go, checking often and try to anticipate when the kerf starts to wander and flip the board at that point. As soon as something "feels" different, check to see if there is a problem. Eventually, you will get better at it, but if you are sawing a lot at one go and get tired, expect your technique to deteriorate.
Five, vary your stroke in terms of where you hold the saw (near the handle tip, or up near the tang) and where you put your body relative to the saw/cut to eliminate your body getting in the way and see what works best for you.
Six, don't give up. It can sometimes be frustrating (as you are no doubt aware) in the beginning, but with practice and persistence you will overcome the problems you are having and not ever worry about it again (except to perhaps explain how its done to your kids or a friend sometime in the future)

Good luck and let us know how its going,

Steve

Thanks for the great advice, I guess it'll take some practice to get it down. You're correct in assuming in was a rip cut. I haven't done large enough cross cuts to notice a problem but I'll probably have to work on that in the future as well. Still I think the j-saw is a step up from the traditional western saw and wouldn't go back.

I also thought that the way the blade is connected to the handle might exert more force on one side than the other, affecting the cut. Undoubtedly the problem has mostly to do with my technique, but I like to tune my tools properly so that it makes learning that much easier (and enjoyable). Are there any common tuning practices for japanese saws that might shed some light on the issue?

Its possible that the blade/handle connection could affect the blade, but you should be able to see that as the blade being other than flat and straight. I have found that some of the replaceable blades are even more flexible (they are very thin - almost as thin as a dozuki which requires a back to keep it straight) than hand made blades and are thus more prone to unintended flex. But better to learn on something $20 and master your technique, than spend a few hundred and fire it at the wall in frustration

There's not much you can do with most machine made saws - they have impulse hardened teeth which are too hard for a file to sharpen (unless you find a diamond file small enough - I've never seen one) and DIY hand sharpening, though not impossible, is quite specialized in any case (thus the plethora of replaceable/disposable blades).

Keep your blades clean and rust free (oiling the blade helps in this regard -many people find that camellia oil works well and doesn't cause problems with the wood) and although they are flexible, they have a limit, so be careful lest they bend/break. Also, forcing a small saw in a big cut can require more force and thus cancel out the expected accuracy and ease. So big cut (as in thick wood) - big saw and small cut - small saws (although you can use a bigger saw). For long cuts with a ryoba, eventually the opposite teeth also pass through the cut and thus add a bit more resistance, so good to wedge the cut open if you can in this case. A kataba or single edge saw eliminates this problem as the back is thinner than the edge (unless the wood tends to spring closed and pinches the blade - again requiring use of a wedge - a common problem as you know no matter what type of saw one uses).
Other than that, general care of the teeth when not in use to keep them from getting dull or bent. Remember how well the saw cuts now (when its new) and when it stops cutting that way, its getting dull.

Steve

Love your posts, Steve. Nicely said -- all of it.

You should teach. ;-)

Didn't somebody once say, "those who don't know how, teach"?

But thanks for that, Becky.

Originally Posted by Sheets

...(unless you find a diamond file small enough - I've never seen one)

I did find one (a feather profile diamond file) on a Chiawanese import stall at a woodworking fair, but have not been able to find any since.

You can give tip-hardened teeth (most replaceable blades) a once-off light touch up, but beyond that you remove the hardened metal layer and it becomes counter productive.

And, because they are so hard/brittle, I have found that the teeth on replaceable blades don't take too kindly to being reset.

Blacksmithed blades don't have these problems, but very few of us have the skill to properly sharpen them, let alone reset (metate) them, or for that matter afford them....

Fortunately the replaceable blades are reasonably priced and last quite well.

Neil

Thanks for another insightful post, I now know that much more about my tool.