Rip saws- Question about ppi

One other comment

Patrick Gibbons, Houston

>I also understand that a courser pitch is harder to start but one gets use to it with experience. That argument doesn't give me a satisfying answer.

Re: One other comment

James Watriss

>I'll take a stab at this one. Please note that some of this is ocming out of my ass, but the logic seems to fit, and some of it seems

I know you're ok with a harder to start pitch, but sometimes it's not just harder to start... it's harder to push, all the way through. Every time a tooth hits, it slows the saw down, and that means you have to start it again (to an extent) after each impact. Now, with small teeth, they aren't taking much out at a time, so they generally keep moving through the cut, but if you were using a 3 PPI, you'd feel the vibration of each tooth hitting and slowing the saw down. Try taking huge chunks out of white oak like that. UGH!

Which brings up another problem, come to think of it. If you are actually successful with using such a coarse saw on white oak, chances are there would be some really good tear-out on the other side of the kerf. White Oak just does that sometimes. Smaller bites mean less of a grab with which to tear something out. I'm sure similar problems would be experienced in other woods. White oak just comes to mind because I've been using it lately.

Another answer I'm able to pull straight out of my backside is that with teeth hitting more often, it's just a smoother cut, because the teeth are impacting at a higher frequency that doesn't rattle the board or the woodworker as much. There's also less time for the saw to accelerate between tooth hits, meaning the stroke is smoother and more regular. Even power tools will display this sort of result. More teeth make for a cleaner cut, even on a 3 hp table saw. It's all about cutting down on rough vibrations sometimes.

And... Less effort on the part of the user also means there's more accuracy due to the fact that it's easier to control. Because your effort isn't going into just pushing the damned thing, you're able to pay more attention to making sure it's going where it's supposed to. And I know, you think you'll get used to it, and eventually be able to control your tools if you can just do [insert whatever it is here] correctly. That's not a satisfactory answer for me. It's why we keep our tools sharp... less effort wasted on pushing means more energy left over for controlling. You shouldn't have to get used to more effort. I suppose if you're rough-hogging planks from a tree, sure, by all means use one of those .25 TPI woodsman saws. But if you're trying to make a smooth, controlled cut that won't require much in the way of planing afterwards, I think more TPI will make youre life easier. It's not just about making the cut. It's about making the cut go where you want. And since so much of the saw's direction is determined in the first few swipes, I'd rather trade accuracy for speed there anyday.

Incidentally, if you look at a Japanese Ryoba style saw, you'll see that the Rip teeth are graduated in size. This way you can start out slowly and start hogging your way through the wood once you get going. So... the best of both worlds, I guess. Chalk up one more reason to use Japanese style saws. ;)

Re: Rip saws- Question about ppi

Dan Clermont

>My D24 is around 6 TPI and fine for what I do. When it is sharp it cuts quickly and leaves less of a mess cause of the smaller set.

I think 3 and 4 TPI is geared more towards carpentry

Dan Clermont

Re: Rip saws- Question about ppi

Christof Hartge

>Hello Patrick,

bigger teeth in my understanding don't automatically result in a quicker cut. But bigger teeth have more room to store the saw dust. So deep cuts, soft and/or wet wood require bigger teeth, whereas hard and dry woods are better sawn with smaller teeth (and little set).

Christof.

Re: Rip saws- Recchione?

Adam Cherubini

>Dear Patrick,

If I'm correct, the procedure for ripping out stuff is to saw proud of the line and then plane to the final thickness.

Not always. This is not, should not, be SOP. And in general I don't recommend it. Take your best shot. You can always clean up later. But you're getting confused about saw teeth. Here's the skinny as I understand it.

Michael Recchione (or any of you good sawyers), would you edit/fact check this post? It woud be nice if I got this right for Patrick.

You're right that coarser teeth leave a rougher surface, but we don't choose tooth pitches for surface quality. As a rule of thumb, our saws work best with 6 or so teeth in the kerf. So you use fine saws on thin material. You probably want to know why:

A coarse saw may crack a thin workpiece. A fine saw's fine teeth clog when sawing thick wood. So you want to balance these two extremes. 6 teeth in the kerf is teh number I remeber. Your magic number may be greater or less.

Hardwoods and softwoods and ease of starting are all a function of rake, not pitch. Higher rakes are easier to start, easier to push and cut slower. Lower rakes are fast cutting but difficult to start. And yes, you get used to it. You realy want to focus your effort behind your teeth. Negative rakes (forward swept) are weaker teeth that cut aggressively.

Now my rip saws' teeth varying in both pitch and rake from heel to toe. And that's another story (but you can guess why they are that way).

Good luck with your saws

Adam

P.S. Isn't it true that this is al the same for power saws?

Re: Rip saws- Question about ppi

Warren in Lancaster, PA

>The ideal number of teeth varies with the thickness of the material, but I think most people do the bulk of their ripping with a single favorite saw. Your 6 pt will answer for most purposes. If you saw a lot of stuff that is 2 or 3 inches you might consider a coarser saw. I have a 4 pt framed saw for heavy stuff and resawing.

Sawing to the line. If one edge is planed already, I mark with a marking gauge or panel gauge and saw somewhat off the line and plane to the line. The underside usually gets a little more beat up from sawing. If the board is all rough I mark oversize and saw on the line.

Re: One other comment

Patrick Gibbons, Houston

>James, being harder to push is a relative thing. I don't think it would be so hard that it would be considerably more so to do it. Also, I don't need to control the cut that much if I start it right. All I have to do is push it. A well-sharpened saw in a correctly started kerf goes where it is supposed to. Smoothness of surface, as I said in my original post, is not the issue. The surface is planed to final demension so it's not going to matter. I have never, ever experienced tear out from a rip cut on any material. That comment had me confused. The opposite side is always the better looking side.

Re: Rip saws- Recchione?

William Duffield, on the Cohansey

>You and James are getting there. Saws are hard starting because they have too few teeth in the wood, especially if you start your cut at the corner. This allows the blade to move sideways, and the next tooth hits the surface flat on. Once the kerf is long enough, the teeth in front in the kerf keep the following tooth aligned with the kerf by dampening sideways vibrations, where it cuts properly with the point only, even on entry. So, if your wood is too thin in relation to the size of the teeth, every stroke is a starting stroke, because the saw can move sideways in the kerf, and the width if the kerf is not controlled. This gives both a rougher cut and makes the saw harder to push, and might even break teeth. Usually hand saws have alternately set teeth, so you need at least two teeth in front set the same as the tooth that is beginning to cut, and two teeth with the opposite set in front, on the other side of the kerf, in the kerf, to keep it straight. If you have too few teeth in the kerf (and when starting the cut), something similar happens to the tooth as it exits. Lateral forces on the tooth tend to push it towards the middle of the kerf, narrowing the kerf at the exit, and pinching the next tooth. Again, you need a minimum of two teeth on each side behind the exiting tooth to keep the saw moving forward, instead of sideways. If the blade is moving faster and is more flexible (as in a bandsaw blade) even more teeth in the kerf are needed to dampen lateral vibrations to keep it cutting easily, smoothly and cooly. I'm sure this is not as clear as it should be, but I don't have any skill in creating animated drawings that might show more clearly individual tooth tracks in short kerfs.

An "Ah ha!" Moment

Patrick Gibbons, Houston

>I already knew that rake dictated aggressiveness. Reading Pete Taran's monograph on saw sharpening gives a full explanation of this. He comments that around 1900 or so saw manufacturers started putting a 5 to 10 degree rake on rip saws for ease of starting for the sawyer. I also have had the experience at one time or another of splitting thin wood with a saw. I didn't know exactly why but I could feel the effect. The number of teeth in the kerf is something I think I remember being discussed here in the past. It's a concept that makes sense to me but I have never had it impressed on me til now. Ah ha! However, it seems to me that number of teeth do have an influence on speed of cut. I have a 5.5 ppi rip saw that is essentially the same rake as my 6 point but it seems to be faster than the 6 pointer. I do not deny that I may be taking it for granted that the rakes of the two are the same but in reality are different. All this is considered in preparation for beginning to sharpen my own saws. I like to know why as much as what to do on anything. Yes Adam I see why different pitches from heel to toe can be beneficial but I wonder how much so it is? Any observations?

Speed

Adam Cherubini

>However, it seems to me that number of teeth do have an influence on speed of cut. I have a 5.5 ppi rip saw that is essentially the same rake as my 6 point but it seems to be faster than the 6 pointer.

There are influences and there are influences. Slight variations in pitch probably don't have as profound an effect as other attritbutes. Thin blades, and saws with less set cut faster. Low pitches cut faster. Most of all, sharp saws cut faster. I don't think I could look you in the eye and say I could tell the differnece between a 6 tooth saw and a 5 or a 7, all other things being equal.

Anyway, I'm always happy to hear folks are using hand saws.

Adam

Re: Rip saws- Recchione?

paul womack

>If I'm correct, the procedure for ripping out stuff is to saw proud of the line and then plane to the final thickness.

I though so too; but Adam quoth:

Not always. This is not, should not, be SOP. And in general I don't recommend it. Take your best shot. You can always clean up later.

So, if you had some "thick enough" raw stock, and wanted your final piece to be (say...) 3/8", both surfaces visible in the final use, what would your recommended procedure be?

BugBear

Re: Rip saws- Way too long of an answer

L. Hanson

>Sorry if this goes on too long...

While this is a seemingly simple subject, it has important ramifications. Recently, I was asked by someone both why you would need more than one rip saw if you have one that is 6-8 TPI or so, and what the reason for having a fine-toothed (10+ TPI) handsaw was. I won't get into blade thicknesses or delve too much into rake angle, but those are considerations as well. Anyway, this was my response:

First off, for a saw to work properly, it has to have a certain amount of teeth within the wood it is cutting. Too many, and the teeth fill up with sawdust and no longer cut effectively. Too few, and the saw gets too hard to push through, leaves too rough of a cut, and can tear out large chunks of wood with it. First - we'll look at having the right amount of teeth in the wood.

First - what is the 1/2" bench chisel of rip saws - the 'universal' rip saw? After all, most of us have a band saw or a table saw, and uses them for this purpose. Well, I was taught was to choose a saw for ripping that has no less than 4 teeth for the thickness of the wood being cut, and no more than 8. For an example - an appropriate saw for a 1" thick board would be from 4 to 8 PPI. Subsequently, a 3/4" board would require a saw in the 6 to 10 PPI range, and a 1/2" board in the 8 to 12 PPI range. Right in the middle is an 8 point - which is a fair compromise if you were to only have one, and ripping isn't something you do everyday.

How about the 'universal' crosscut saw? The same basic logic applies, but because cross grain is more prone to tear-out, instead of 4 to 8 teeth in the wood, the numbers should be 6 to 10. Crosscut saws are sharpened to cut differently to address the tear-out problem. Where rip saws act like a series of chisels chopping through the wood, crosscut saws act more like a series of knife cuts - the rake angle is increased to reflect this, so the teeth literally cut the grain as it goes along, where a rip saw's action is more analogous to chopping the wood as it proceeds through the cut. As a result, crosscut sawing is a little slower than rip sawing.

So there it is - for general casework and light construction, the 'universal' rip saw would be in the 6 to 8 point range, and the 'universal' crosscut saw would have 8 to 10 point per inch. This jives with what I've seen in the wild - most of the saws I've found are in these ranges.

These numbers might seem a bit coarse to you - but remember, you don't saw the board straight across, you saw it holding the saw at a 45 to 60 degree angle to the plane of the board - making the number of teeth that are actually in the wood one and one-half times as many. So, a 4 PPI saw in 1" of wood actually ends up with between 5 and 7 teeth in the cut at a time.

Why isn't having a 'universal' saw enough for most purposes? Well, it can be - but it's the same as having only two chisels, like say a 1/4" mortise and the universal 1/2" bench chisel. Sure, they will do the large majority of the tasks at hand, and you can even modify your project to fit the tools you have on hand - but it does limit you quite severely. What about projects that would work better with a 3/8" mortise? There are times when having a more diverse selection - different sizes, and special purpose chisels (paring, mortise, bench, butt, or slick) can make the work much easier and give you better results.

How to determine the best saw for the job? Well, now that you've determined the range of PPI to use you might think "OK - I'll just grab the coarsest because it will cut the fastest". That will be OK most of the time, but what about the finished edge? Are you going to clean the cut up with a block plane, chisel, or leave it raw? Well, that depends on the final use. Cleaning up the saw cuts for rafters would seem a waste of time. The same can be said for tenon cheeks, where fit is the most important factor. But if you are doing trim work, appearance is more important, so there you might saw just short of the line and clean up the cut as described. So, to state the obvious - trim saws are always finer than saws used in framing because of these differences as you are usually working in thinner, drier woods, and prefer an edge that requires less clean up with a saw that's less prone to damaging the wood.

Which brings up the next point - it also matters which kind of wood you are cutting - is still softwood, hardwood, still green... Wet wood requires the coarsest saws, and softwood and construction lumber generally springs back more (which tends to cause finer saws with less set to bind more often), thus require a coarser saw than dry hardwoods, where using too coarse of a saw in dry hardwood might splinter the wood too much for you to be able to use it.

So - if you are using hand saws more often, it pays to have more than one configuration - as was the case "back in the day". Most carpenters/joiners had several saws they brought to work everyday, usually a couple of each - rip and crosscut - one each of finer and coarser for use on finer or rougher work, and then probably a 'universal' saw they had for general purpose work. Great granddad's case of saws contained 6 such handsaws he carried with him to each job site.

HTH

Leif

NorseWoodsmith.com

If I understand... (long-sorry)

Adam Cherubini

>Bug,

Are you asking if I had to rip a board to a given width where the ripped edge would show in the finished piece what would I rip to?

Not to argue with the question, but it rarely happens that I need a fixed width and that the surface is a mating surface. Period furniture just isn't designed that way. If its a non-mating surface who cares what dimension I rip to?

But to answer your question, I make decisions like, split the line, remove the line or leave the line. Rarely do I leave the line proud and plan to correct back to it. It happens accidentally mind you. (I'm talking about a pencil line, BTW)

If I need a board of a given width (or length for that matter- who likes planing end grain?) my SOP is to saw to that width. If I screw up, (and I always do) I deal with it. I may have to square the edge with my try plane. But this amount of planing is often negligible.

I believe your fellow countryman David Pye talked about this with his "workmanship of risk". Leaving excess is akin to Pye's "workmanship of certainty" in my view. It is preselecting failure in my mind. Planing is what I do when I fail to saw correctly. Paring dovetails is a better analogy perhaps. It is my goal to never pare.

Anyway, sawing isn't that hard. The problem I think a lot of guys face is that they put about 1% into saws and sawing and the other 99% into planes and plane sharpening. You have to practice your sawing and develop your saws and horses. So I would recommend instead always (or nearly always) sawing to the line just to practice.

I also recommend just practicing. I used to go into my shop and just cross cut something straight and square, 1" at a time until the board was gone. I found the ability to accurately cross cut was holding me back from completing the projects I wanted to complete, in the time I wanted to complete them. Lately I've been cross cutting as little material as possible and leaving a uniform thin slice of end grain. Its fun. Try it! It'll also show you what you are doing wrong. Working in front of a mirror or better yet, a video camera is a learning experience as well.

Adam

Gets close to the same thing

mike recchione

>Given the alternate set, your explanation puts a minimum of 4 teeth in the kerf. I had always heard 5 or 6, but it's on the same track.

Re: Gets close to the same thing

William Duffield, on the Cohansey

>Well, I'm not down there in the cut looking at what's going on, and there is lots going on, but I suspect that four teeth is only a "first approximation". Remember that, because of the set, the side of the tooth does not slide against the side of the kerf. You couldn't push it if it did, of course due to the increased friction. But that means that there is a lateral point force by the first and last tooth against the side of the kerf, that easily displaces the wood fibers there. So, my theory is the first and last tooth in the kerf don't do much to counteract the saw moving laterally in the kerf, especially if your stroke is not straight, or if the unsupported tip of the saw is whipping around. So six is probably closer to the right answer. This is a dynamic problem, so static analysis is insufficient to understand what is going on.

Re: Rip saws- Question about ppi

Todd Hughes

>Maybe i have lived a sheltered life but I don't know if I ever saw a 3 or 4ppi rip saw that came from the factory like that. Have seen some strange sharpening jobs esp. on older saws that look like they were done in the dark by Chimps that might have been that coarse but am not sure. I believe the largest teeth that Disston offered was 4 1/2....thogh don't think I remember ever have seen one. By far in my experance the most popular size tradtionaly [talking 1850s-1900s] is 5 1/2. then 6 I would say a rip saw with finer teeth then 7 would be a rariety.Personaly I would suspect it to be a cross cut that was re filed into rip...I just don't see the need for a fine rip cut and since rip cuts were probably tradtional longer on the whole then a cross a faster saw was probably appreciated....I think you would be well served with a large 5 1/2 ppi rip and then maybe a small panel rip saw with 7ppi. Probably no real need for the panel rip but hey a good excuse to get another saw.....Todd

Re: Rip saws- Question about ppi

L. Hanson

>This might interest you, Todd:

The bottom saw is an Atkins 3-1/2 point saw, and is marked as such - from the factory. This particular one belongs to a buddy in Australia, where it seems to me from the reports I get that while not common, they aren't unheard of either.

Not available in all years, I do know the 1918 catalog had Disston #7's available in 4 point.

Leif

NorseWoodsmith.com

Re: Rip saws- Question about ppi

Todd Hughes

>Guess thats why I never saw one...haven't ever been to Australia!....Where in the Disston 1918 catalog does it show a no.7 with 4ppi? I couldn't find it in my old one. Just had a section showing the different size teeth from 4 1/2 to 12......Todd

Re: Rip saws- Question about ppi

Angus Barclay, in New Zealand

>Hello Patrick,

an important reason for needing a variety of different tooth sizes is that different size saws do different tasks. There isn't really a one-size-fits-all saw, just like a jack plane isn't really a smoother or jointer.

I use an aggresive 4ppi rip for resawing and cuts in material more than 4in thick, a 7ppi rip for other dimensioning work and an 11ppi rip backsaw for cutting joints. I couldn't imagine using just the 4ppi rip saw to do all these tasks - it is best suited to stock over 4in thick and would make a poor job of cutting thinner stuff.

regards

Angus Barclay

Re: Rip saws- Question about ppi

L. Hanson

>I actually got the 4 point reference from the disstonianinstitute.com page on #7 saws:

No. 7 page

It shows a 28" #7 4 point saw as being available. I don't think he got that information out of the little pamphlets Disston put out, I think that info is from the bigger wholesale catalog.

There's also a D-8 listing with 3-1/2 points on that model's page:

D-8 page

Here's a photo of a 4 point D-8:

4 point saw

I am assuming his information is accurate...

Leif

NorseWoodsmith.com

Re: Rip saws- Question about ppi

Todd Hughes

>Interesting...I still can't find anything in my original Disston 1918 241 page hard back catalog that says they sold saws coarser then 4 1/2. Oh well I did enjoy looking at the Disstonian institute...actually think those three panel no7 saws might belong to me [I forget what photos of my saws I sent him]....Would be curious to see if that 4ppi no. 8 is stamped 4 on the heel or has been retoothed. Looks like it has been sharpened a good bit and Disston with rip saws coarser then 6ppi had gradurated teeth where they were 1 point finer at the tip then at the heel something that this seller didn't say this saw has which makes me further think it might be retoothed ....Todd

Re: Rip saws- Question about ppi

L. Hanson

>Well, maybe it is for real, and maybe its been re-toothed - but really, I don't see any reason why it couldn't be a 4 point saw... I dare say many people wouldn't be aware of the graduated teeth on the coarser saws, so a seller failing to mention it doesn't say a lot, at least to me. Not all sellers are that knowledgeable about the items they are selling.

If you look at this page in the 1912 book disston put out on hand saws (hosted on the Rose Antique Tools web site), you can see that they show teeth all the way down to 3 points:

Graphic of teeth in disston catalog

Now - this is PURELY hearsay, but I've heard tell of 3 point disston rip saws, and that they are highly sought after by some timber framers. Just because you haven't seen one, doesn't mean they don't exist!

Leif

No need to go to Oz

Bill Houghton, Sebastopol, CA

>I can't recall the points per inch, but when I worked at the local junior college a million years ago, they had a dock saw with incredibly coarse teeth and an aluminum handle. Not sure why, since there was no water on the campus except the swimming pool, and I never noticed a dock in that during the hours I spent cleaning it.

It was only my strong conscience that prevented it following me home.

Yup

Todd Hughes

>I have a few of those and I also got a Disston Ice Saw that has 6 PPF ,[thats 6 Points Per FOOT !] filed rip too so guess I have had seen a coarser toothed factory rip saw and just didn't realise it.....I think due to that tough Anartic ice used in Australia thier ice saws normaly are 3 PPF....Todd