A Minor Problem when using the Rip Saw

[Andy Kev.]

Good Morning,

and I apologise for yet another beginner's question. I've so far found that in woodwork practice seems to be more quickly rewarded with significant improvement than almost any other activity I've undertaken. There does, however, seem to be on exception to this and that is rip sawing wood to rough size. I encountered it again yesterday when trimming off the triangle (i.e. the outer tree trunk bit) from the sides of some four foot lengths of American Walnut.

I've got to the stage where I can keep to my marked line fairly accurately but I find myself sawing at a slant in the vertical plane i.e. as you look down on the plank, the cut slants a degree or two inwards towards the centre of the plank so that it ends up being about an 1/8" narrower on the underside than on the top where the mark was. This is of course not a major irritation as it is easily enough corrected with a plane. It's bothering me more as a skill acquisition issue: I would quite like my rip cuts to run vertically downward through the board. My best guess is that this is something to do with my body position in relation to the plank. I'm also very right handed e.g. while I can saw the left side of a dovetail (from top left to bottom right), I'm so bad on the other side that I've taken to turning the board round to repeating the same cut on the other side. Could this degree of right-handedness be part of the problem with the rip sawing? Are there any general tips which you would recommend for ripping?

 

[JohnPW]

I had this problem yesterday, I think I held the saw (cheapo Aldi hardpoint) vertically or near enough vertically but the cut was slanted, by a much larger degree than the saw. Then I used another saw and the cut was vertical enough.

I read that if the set of the teeth are not equal, that can make the saw saw off line. So I checked the Aldi saw and yes the teeth was sticking out more on one side, the side the slanted cut was pointing.

 

[Andy Kev.]

I've just had a look at my saw - a good one: a Pax by Thomas Flinn -and the teeth are set bang on, so it definitely looks as if the problem lies with me.

 

[KevM]

Andy Kev - are you aware of any dominant eye issues? I found out a few years ago that I'm strongly cross-dominant (it's not as kinky as it sounds!) - I'm right-handed and left-eye dominant.

How to test?
Look at an object a few metres away.
Point at the object with an extended index finger, pencil or similar*
Now close each eye in turn and observe how/if the alignment of your finger changes.

For example, if I look at a post ~10 metres away and line up my finger with both eyes and then close my right eye nothing changes, if I then close my left eye my finger appears to point about 1 metre to the left of the post - this means my left eye is dominating my stereo vision causing a significant parallax error.

When lining up a cut I now close my dominant left eye and blame the rest on the tools.

*Another technique is to cross both hands with your arms extended in front of you so that you form a triangular viewing hole and align that with the object.

http://en.wikipedia.org/wiki/Ocular_dominance

Edit: a nice clear explanation here - http://swingleydev.com/archive/get.php? ... t_thread=1

 

[Andy Kev.]

KevM,

I'm definitely right-eye dominant as well and your finger test confirmed it.

 

[woodbrains]

Hello,

The 'triangle' you are talking about is usually referred to as the 'waney edge' or just the 'wane' BTW

I think your error in sawing is slightly more unusual than the normal problem. Often people position their body too far to the left of the saw, so they can see the line, and this makes them cut more outwards at the bottom of the cut. If I am reading correctly, you have the opposite effect. Are you leaning too far over the saw to see your cut? Ideally, your head should be above centre of the spine of the saw, so you can see with each eye, its respective side of the sawcut. This usually helps with the usual problem, perhaps it will sort yours out, too.

Mike.

 

[KevM]

Other factors that can cause problems with sawing are grip and stance. The recommended grip is to have your index finger extended along the side of the blade, so you have your thumb and lower three fingers wrapped around the handle and index finger extended. The basic grip is easy to master, the trick is to learn to relax the grip. If you hold the saw out in front of you and grip it loosely it should point straight and vertical, if your grip is too hard the tension in your arm will turn your grip slightly and the saw will roll slightly to the side.

Stance - be comfortably lined up with the work piece so that you're just moving the saw backwards and forwards without excessive downward pressure, i.e. try to exert as little influence on the blade as possible.

A good saw will naturally want to cut straight - it's our bad influences that try to force it off the straight and narrow.

 

[Andy Kev.]

Hello,

The 'triangle' you are talking about is usually referred to as the 'waney edge' or just the 'wane' BTW

I think your error in sawing is slightly more unusual than the normal problem. Often people position their body too far to the left of the saw, so they can see the line, and this makes them cut more outwards at the bottom of the cut. If I am reading correctly, you have the opposite effect. Are you leaning too far over the saw to see your cut? Ideally, your head should be above centre of the spine of the saw, so you can see with each eye, its respective side of the sawcut. This usually helps with the usual problem, perhaps it will sort yours out, too.

Mike.

Mike,

I think you may have identified the problem there because there was no way on earth that I was positioned too far to the left of the saw, determined as I was to look right down the blade. That's made me think that that too-far-to-the-right body position probably causes a slight change in the angle of the hand that was too small to feel. I'll shift myself an inch or two to the left.

And "wane" is now a part of my vocabulary!

KevM,

my general stance and grip are as you describe and it's only with ripping that I ever have a problem and I'm certainly inclined to agree that it is our bad influence on an innocent tool which is the problem.

 

[lanemaux]

No idea if this is relevant or not , but according to St. Roy of Underhill ripping entails turning the stock from one side of the rip to the other quite frequently. Sawing to the line marked on both sides while it faces you. As near as I can figure this should help in two ways. You won't be adopting an uncomfortable stance and then repositioning over your cut every few minutes to see the lines and any possible error will be reversed each time you turn the workpiece. Belt and suspenders so to speak.

 

[Graham Orm]

Assuming you have your board lying flat, try lying your saw down as you cut, along the line so that the cut becomes a back and forward motion rather than an up and down motion. This will make the saw/wood contact area much longer and will stabilise the saw, it will also make any angles you are creating more visible as you will see the saw leaning one way or the other.

 

[woodbrains]

No idea if this is relevant or not , but according to St. Roy of Underhill ripping entails turning the stock from one side of the rip to the other quite frequently. Sawing to the line marked on both sides while it faces you. As near as I can figure this should help in two ways. You won't be adopting an uncomfortable stance and then repositioning over your cut every few minutes to see the lines and any possible error will be reversed each time you turn the workpiece. Belt and suspenders so to speak.

Hello,

The thicker the stock, the more relevant that would be, since a tiny error in angle from vertical would be exaggerated by by thickness, and you'd want to nip that in the bud before it got out of hand. If you can train yourself to cut vertically, it would save a lot of labour in turning heavy planks, time and again! With sawn stock it is often not too relevant being too accurate, as twist/cupping in a board makes it all a bit academic, and only true square edges can be achieved once the faces are flattened.

Mike.

 

[lanemaux]

Quite right Mike . Not that much of a problem for me as it has been some time since I've had any heavy pieces of stock in the shop. Most of my ripping has gotten to the lash it in the vice and reposition as needed stage, box stock and hobby doodads and such. Point well taken though,would hate to rotate barn beams every 15 or 20 strokes.

 

[xy mosian]

Hi, My twopen'orth.

It is only necessary to look at the point where the blade meets the timber, to make sure the cut is following the line. The other side of the saw will follow.
Adopt a stance that allows clearance between the elbow and your body on the back stroke. Otherwise you will move the arm away from the body and get a sloping cut.
I hope this helps.
xy

 

[Andy Kev.]

I've just done three more edges but this time I clamped the wood to the low dining table bench I use as a work surface for ripping. That was a huge improvement as it meant that I didn't have to kneel on the wood and so be too far over to the right. This in turn meant that I had a much easier arm and sawing action (the sort of thing xy referred to) and so the cut while not uniformly vertical was much better than my previous efforts.

Thanks to all of you for the advice.

 

[Jacob]

Ripping easiest done downwards with the workpiece at knee height on saw stools. One knee on the piece (or sit astride if narrow enough and both hands on the saw) - saw near vertical. It's a fast and energetic action and not very accurate, say from 1 to 6mm from the line depending on what you are cutting (offset on to the waste side of course).

 

[Andy Kev.]

Ripping easiest done downwards with the workpiece at knee height on saw stools. One knee on the piece (or sit astride if narrow enough and both hands on the saw) - saw near vertical. It's a fast and energetic action and not very accurate, say from 1 to 6mm from the line depending on what you are cutting (offset on to the waste side of course).

I'm not quite up to "fast and energetic" yet, maybe "steady and rhythmic" best describes my style. Sitting astride and using both hands never occurred to me. I might give it a bash.

 

[Jacob]

Ripping easiest done downwards with the workpiece at knee height on saw stools. One knee on the piece (or sit astride if narrow enough and both hands on the saw) - saw near vertical. It's a fast and energetic action and not very accurate, say from 1 to 6mm from the line depending on what you are cutting (offset on to the waste side of course).

I'm not quite up to "fast and energetic" yet, maybe "steady and rhythmic" best describes my style. Sitting astride and using both hands never occurred to me. I might give it a bash.

Fast and furious because rip cuts tend to be long so it's more efficient to do a roughish fast cut and finish with a plane, rather than aiming to be precise. Or if you are only removing a bit from the width it might be quicker with an axe or a scrub plane.