Full Chisel Blog

June 26, 2008

Cross Cut Saw verses Rip Saw

Filed under: Dovetails,Sawing,Sharpening — Stephen Shepherd @ 7:44 am

The great debate, the endless questions, the historic evidence, the ideas and theories, the dilemma, rake, fleam angle, taper, belly, grip,  set, down to the saw bolts has been discussed where ever woodworkers gather and talk saws.

I will be discussing saw sharpening only briefly (if that is possible) as it is covered elsewhere including here.  I will talk of set (oh wait I did that part) but I am going to discuss whetting or side joining saws as the final and I believe important step in properly saw sharpening.  I will get to hammer straightening a bent blade which I should have done earlier but there is nothing I can do about it now.

A cross cut saw is used to cut across the grain of the wood and are sharpened like knife points to score then shear the fibers of the wood.

A rip or splitting saw is used to cut with the grain and are sharpened like chisel points (or little tiny plow plane blades) to excavate the wood from the groove.  Usually with fewer teeth per inch and larger gullets to remove the dross.

Now in order to blur the line a little, here is a RIP/CROSS CUT saw blade in a nineteenth century American pattern bow saw, curly hickory arms, maple handles, white oak stretcher and the walnut and mahogany toggle is inspired by Eric Sloane.  The blade is after one illustrated in Salaman.

Rip / Cross Cut Bow Saw

And while it may be difficult to see the blade is cranked at 90 degrees in the middle of the thin blade.  The portion on the right is sharpened rip and the portion on the left is sharpened rip.  I use this saw to remove the waste between the pins when finishing my dovetails (tails first, as I gang saw the tails).  It is surprisingly easy to use and astounds people when I demonstrate how it works.  It cuts (rips) down to the score line, then when the crank (with its tapered transition) is pushed it begins to cut (cross cut) to finish the removal.  Attention must be paid to the angles of the pins and sawing is done on the money side (the one that shows). 

Tooth count: the general reference for the coarseness of saws is TPI or teeth per inch.  Now there are PPI or points per inch and I don’t know why there is a difference, perhaps a saw maker could respond?  Rip saws usually have fewer teeth per inch with larger gullets to remove the dreck rapidly as is their want.  Cross cut have finer teeth and vary remarkably as do the teeth of rip saws.  And here is a general guideline (I avoided the use of the word rule), finer tooth patterns are for thinner boards and coarser tooth patterns are for thicker wood.  This helps eliminate the saw dust easily.  Fine toothed saws, either rip or cross cut will tend to bind up on thicker boards.  Finer teeth produce finer cuts and are more suitable for thin pieces of wood.

Some blades are taper ground with the teeth being the thickest and the back being thinner.  This helps reduce binding and allows for little or no set to the blade and still cut and not bind.  Some open hand saws are tapered in the same way but also tapered to be thinner at the tip and tapering to thicker at the handle.  This of course makes the nicker nib nice and thin and capable of breaking off.  (It is easily filed back into the tip of the blade).  That nib works just fine, it doesn’t need to be as wide as the teeth, all it needs to do is make that fine nick on the edge of the board to start the cut. 

And the reason for the blades being wider at the handle or heel and narrower at the toe?  Because you can use the narrow toe to correct any errors in sawing as the narrower tip allows for correction to an arrant saw kerf.  Like a narrower blade can make a tighter circle, a narrower part of a blade can do the same thing.

And apparently not all saw were provided straight as many had bellies (breasted) with the teeth being higher in the center.  Now I am not talking those floor or veneer saws but open hand saws, cabinet and panel saws (maybe there is a distinction there).  And the P.S. Stubbs blade I have, albeit a web blade has a belly.  I am not sure it could be called breasted because the entire blade as a belly (convex), the back being slightly concave.

And of course there are those progressive toothed saws, finer at the tip and coarser over the rest of the blade, this is to assist in starting the cut after using the nicker nib.

And there are examples of both cross cut and rip in open and framed.  The open saw is lighter in weight but can have a much thicker blade than a framed saw.  The frame saw has the advantage of using thin and narrow blades for certain applications like cutting curves, they can also be used to hold thin and wider rip blades for splitting boards with a thin kerf.  The disadvantages of framed saws are weight (which isn’t that much of a disadvantage) and most importantly limited cutting because of the frame.  At some point, unless ripping off the edge of a board the frame will get in the way.

The advantage of the open saw is that it has no frame (and no back) so it can cut through pieces of wood that could not easily be done with a frame saw.  Speaking of back saws, as many of you know I am not a big fan of backed saws, I am down to only one very small brass backed Gent’s Saw that I use for fine work.  Larger back saws have always felt awkward in my hands and I never found one I liked, and I have gone through a couple dozen.  I think this is another marketing ploy by manufacturers, ‘a thinner saw kerf’, I think less saw, more money.  Why would anyone in the nineteenth century worried about the size of the kerf?  Ok, marquetry, but that is a different saw.

When I saw dovetails, I use my widest (kerf) unbacked dovetail saw, the more wood I can saw out the less I have to remove with a chisel.  If I did finer work, maybe I would want a thinner saw.  But my dovetail saws are all used for general purpose ripping of small pieces, I grab the big rip saw to rip the big boards.

Then there are the saws that need to cut both cross cut and rip, like a fine turning saw, compass saw, coping saw, fret saw, &c, how are these sharpened?  Half and half, the teeth are filed with the hook of a rip saw and the fleam or side angle of 80 degrees.

Stephen

9 Comments

  1. Stephen

    I seem to remember Tage Frid writing about this frame saw technique. While I’ve never had the opportunity to try it, the trick certainly sounds sensible. I wonder if this was a common technique in Europe?

    Gary

    Comment by Gary Roberts — June 26, 2008 @ 10:05 am

  2. Gary,

    I wrote about it in 1981 when Shepherds’ Compleat… came out and I saw it somewhere. So I have made several of these and they are not that hard to make. Maybe in the future I will do a write-up of the technique. I am also going to try and shoot a (pardon the modern reference) video of the saw in use, it is quite astounding to watch. When I do it, people don’t really see it as it happens so fast, so I have to repeat it so they can watch closely.

    Stephen

    Comment by Stephen Shepherd — June 26, 2008 @ 7:11 pm

  3. That rip/crosscut saw is a pretty cool idea, and I can see how it would work, but what happens when you get to the next corner? That is to say, I can see that it will cut down, then cut across, but how do you turn it to cut back up again? Or do you have to cut the left hand vertical first (or right hand, depending on which way the blade is kinked)?

    M.Mike

    Comment by Metalworker Mike — June 28, 2008 @ 2:28 pm

  4. M.Mike,

    I cut the left hand vertical first, then the other and then the horizontal. But this got me thinking of making one that would cut that way, one third oriented properly. Although there is no historic example other than this one which is wonderful to demonstrate.

    Stephen

    Comment by Stephen Shepherd — June 28, 2008 @ 7:34 pm

  5. Do you find that you can easily get the angle you need for a dovetail using this saw, or does it enforce the 90 degree angle, meaning you have to change from rip to cross-cut a bit early and adjust your trajectory while cross-cutting?

    M.Mike

    Comment by Metalworker Mike — June 29, 2008 @ 3:04 pm

  6. By the way… the cord that you used to tension that bow-saw… do you have a source for that or did you have to make it? I’ve found that ‘rustic rope’ isn’t trivial to find these days, but you can effortlessly find _very_ rustic twine, and making rope out of twine is certainly easy, so I was curious.

    M.Mike

    Comment by Metalworker Mike — June 29, 2008 @ 3:08 pm

  7. M. Mike,
    I only use this saw for removing waste of the pins, can’t work on tails because of the angles, must be 90 degrees. I waste the tails with a coping saw and fine blade but more commonly a sharp side beveled 1/4″ chisel that I have reduced the side bevels to facilitate dovetail work.

    The rope is just plain manilla rope that is end spliced. As soon as I finish the rope making machine for the Park where I work, I will have my rope made to order. There are actually some good hemp rope (smaller stuff nothing real big over 5/8″) available, made in Hungary.

    Stephen

    Comment by Stephen Shepherd — June 29, 2008 @ 3:20 pm

  8. Just stumbled on this post (I got behind). I vote YES – either blog about the technique or convince Joel at TFWW to offer the blades for the Gramercy turning saw, of which I’ve made three.

    Comment by Chuck Nickerson — July 10, 2008 @ 5:33 pm

  9. Chuck,

    I will mention that to Joel, I have made several of these blades, maybe I should start making them for sale. They are wonderful blades, not only for removing waste on tails, but people are totally amazed when they see it in operation.

    Stephen

    Comment by Stephen Shepherd — July 10, 2008 @ 7:05 pm

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