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Posts Tagged saw sharpening

Frankensaw; Saw Sharpening Guides

Feb 23

Posted by Brian in Saws | No Comments

I’m finally done with sharpening the last saw on my to-do list. This and the one in my previous post were both acquired at an estate sale over in the Sunset district last year. They’re both Disston No. 7s, but both have been rehandled. The first one I worked on had some sort of modernish handle on it. The one I just finished has a No. 12 handle.

Someone must have liked these saws. They were both rust-free and had pretty good visible etches. Unfortunately, the sharpening on them was crap. The No. 7/12 Frankensaw needed serious jointing (and therefore, serious tooth reshaping) before it could be pointed.

But once at the pointing stage, things went pretty quickly in spite of it being a 26″ saw with 8 teeth per inch. I used a 10 degree fleam angle this time, and used a roughly 10 degree slope on the gullets as well. Here’s a shot of the sharpening in progress:

This picture shows one of the issues that often comes up when sharpening crosscut saws that I’ve been talking about recently, and that is, that the shape that the tooth appears to be can be misleading. Look at the teeth on the right side of the saw in the preceding image. See how they look kind of spindly? It’s a trick of the reflected light. Here’s a close-up, where you can see the reflections and the full tooth profile:

Obviously, there are some uneven spots here, too, like the second-to-left gullet, but those were taken care of on a second pass. but the point is that you have to be careful about what you see. Just be consistent with the angles you work at, look at the tops of the teeth to see when you’re done.

Here is the saw in its finished state:

You can see my fleam guide in the photo of the work in progress. I worked a little on the code for this before starting this saw. My previous version required you to use two different cutouts to sharpen each side of the teeth. That was kind of stupid, because you can see only one side of it at a time. So I reworked it. Here are PDF versions for:

If you know how to use PostScript, ask me for the source code; you can put in any fleam angle you like. (I haven’t figured out how to trick WordPress into letting me upload a .ps file without doing something stupid like archiving yet, sigh.)

Also, I have a PDF tooth pitch gauge (toothgauge) that you might be able to use at some point.

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My Sloped Gullets

Feb 19

Posted by Brian in Old Tools, Saws | 3 Comments

Leif over at Norse Woodsmith did a recent post on sloped gullets. Strangely enough, I’ve been working on restoring a couple of saws lately, and about the time he posted, I was starting to sharpen one of them, an old Disston No. 7. I finished this morning and decided to take a photo of the result. Unfortunately, I don’t have a macro lens, so I can’t get much better than the following shot, and also unfortunately, I don’t think the angle is very good, because you can’t really see the bottom of the gullets too well:

In any case, take a look at the bottom of the brightly reflected edges, and you’ll see that the rear is higher than the front, especially on that tooth all the way to the left. This shot was taken straight from the saw coming off the file, so you can see some burr here and there. You can also see how difficult it is to judge the height and shape of the teeth here. In this shot, it looks like the teeth set towards the camera (the all-dark ones) are a little bit lower than the ones set away, but in reality, they’re all the same. It really is easier to tell by jointing the teeth and filing until the flats are gone.

I’d mentioned in a comment on Leif’s post that the angle I used for fleam and slope was not that great. On further inspection, it seems to be moderate. The fleam angle is 20 degrees and the slope is about the same. I think a 10-15 degree fleam and slope would be easier to file, and I plan to try it out on the other saw I need to sharpen.

All of this theory is useless if it doesn’t work in practice. Here is a test cut in beech:

It’s about what you would expect from a 6TPI saw that’s 26″ long. The important part is that it belches sawdust profusely when sawing, and with a controlled cut, you don’t get much tearout. And it’s always nice to get a 110+ year old tool working again.

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Frame Saw: Important tweaks

Dec 20

Posted by Brian in New Tools, Saws | 4 Comments

After a bunch of sessions with the new frame saw, I determined that it wasn’t working the way it was supposed to. It didn’t cut quickly, the kerf was too wide, and the blade wandered all over the place. I suspected that more than one thing was wrong, and I had a few ideas.

First, I caught on to the fact that the blade wasn’t really sharp, although it had the appearance of being sharp. I really need to learn that if the guy who made your saw doesn’t have a name like Wenzloff, it probably isn’t sharp, so you should save yourself a lot of trouble and sharpen it before using it. Groan.

I reshaped the teeth to have a fairly aggressive zero-degree rake angle, and took a considerable amount of care when sharpening to make sure that the tips were all very close to the same height. The result looks like this:

frame_saw_new_teeth

When doing this, I realized two additional things about this blade. First, it had way too much set, and second, the saw plate is a little thicker than I thought it was. This latter point was a big deal, because it seemed like the tips of the points originally were chamfered or slightly rounded. I couldn’t see this originally, even with reading glasses. And obviously, it makes a big difference in use, because, as I find over and over again, sofa-shaped blades don’t cut wood very well. (I wonder why.)

The difference in sharpening alone was really remarkable. Because the process removed most of the set, it made for a wonderfully thin kerf, and therefore, it tracked a line much better, even though the blade wasn’t terribly taut. And the more aggressive and sharp teeth cut much faster and smoother.

Now, the second problem I was having was that I couldn’t increase the blade tension too much, because the little screws that I was using to hold the blade in place were snapping due to the tension:

frame_saw_failed_pins

Yikes. So I cut and filed a few brads for this purpose:

frame_saw_new_pins

Now that there’s enough tension, I don’t have a problem with the blade twisting around (thanks for the pointer, Dan). The only issue I have now is that it’s difficult to keep the blade straight when tightening it up. Christopher Swingley uses a wrench on the flats, which seems like an idea that might work.

After making these two changes, this saw really seems to be on the right track, and I think I’ll be able to do decent work with it. I already sawed out some 3/16″ slices from a couple of smaller boards (without even marking!), and they came out great.

There always seems to be a lot of discussion about frame saws, and what kind of blade is appropriate. Tom Holloway’s saws use thin blades, and I can attest to how effective they are, having played with them. Bob Easton uses thicker blades from old Disston saws and that seems to work too. It seems to me that there’s more than one way to skin a cat.

A case in point here is what I edited in as a note in my last post, that there’s a version of a Japanese saw, the “oga kobiki” or something, that has a gigantic blade, but seems remarkably easy to use. Check out the pictures in this link if you haven’t yet. You see how that tiny woman is using that huge saw? Look at how beautifully the cut turns out. Oh, how I would love to examine that saw that they’re using.

So it seems that if the kerf is even enough–not too wide, not too narrow, of constant width, and straight–it doesn’t matter how big your blade is, as long as it’s slippery and sharp.

I don’t think this is going to be the last blade for this frame saw. I’ve got some ideas that might make it faster. Let’s just say that the gigantic teeth on the Japanese saw got me thinking.

I also got to thinking that I might need to do something about my saw vise. It works pretty well for small saws, but when you start to file the big teeth, it shakes too much. What to do here? Finally make my own? Cave in and get one of those new Gramercy saw vises? Find someone who has a good one and mug them?

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A D-8 named Sawthra

Oct 3

Posted by Brian in New Tools, Old Tools, Saws | 5 Comments

The last saw to be complete from the pile o’ handles I refinished a while back was a 28″ Disston D-8. The plan was to make it a replacement for the 7 TPI D-7 that I’d been using for a rip saw.

When I first got the D-8, I was somewhat ecstatic. The blade was pretty clean, reasonably straight, and even had its etch. So all I needed to do was refinish the handle, clean off the blade, and sharpen. Easy, right?

Well, I got to sharpening, and about halfway through from the heel to toe, my file started to make strange noises and didn’t want to cut the metal. Huh. It turns out that there was a roughly 8-inch length where someone had done something unholy to the teeth. They were hard, very hard. We’re talking “breaks the teeth off your file” hard here.

I wasn’t going to let a saw make a monkey out of me, though, and managed to work through the hard metal. It seemed to go about 1/8″ deep into the blade. After this, I was tired. Very tired. I thought, well, maybe I should name this thing “Sawzilla,” but quick research indicated that it wasn’t a terribly original name. So here is Sawthra, named after the slightly more obscure Mothra:

disston_d8_sawthra

The Disston D-8 brings me to another thought I’d been having lately, namely, “wouldn’t it be great to have a brand-new D-8?” Then at Bagathon, I made a rather unusual deal with Larry that brought me this saw:

pax_no1

Notice anything familiar about this 24-inch Pax “No 1″ panel saw? Like, maybe, that it’s a total copy of the Disston D-8, even down to the handle and the screw arrangement?

So I really do have a practically brand-new D-8 now. It makes sense, I suppose. The Flinn company tends to catch a lot of flak about its saws, in particular, that the handles aren’t as nice as century-old handles. But they do at least reproduce a true classic handsaw. The blade is taper-ground, for whatever that’s worth. Although I wouldn’t characterize the teeth on this thing as “sharp” (my little carcase saw currently cuts faster than this thing at the moment), they don’t look too bad, and probably need a little touch-up. I’ll wax the blade, like I always do.

The handle? Well, I’m not sure if I want to make a new one or not. To be honest, the handle isn’t that bad. But I always seem to end up making handles.

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A Tale of Two Saws

Aug 19

Posted by Brian in Old Tools, Saws | No Comments

Or, rather, two descriptions. I finally finished the pile o’ handles I was working on, and two of the saws on which they belong are complete:

The one in the back is a 28″ Disston No. 7. When I got it, it was filed at 4.5TPI crosscut. However, this pitch (and the saw’s handle) is far more suited for ripping, so during sharpening, I converted it to a rip saw. For the first time when simply modifying teeth on an old saw, I needed to add some set–there was practically none. Although the surface looks a little funky (strange corrosion patterns), it’s actually pretty smooth, and it tears through wood like a bat out of hell. I have wanted this saw to be complete for a long time. I’ll be using it a lot.

The other saw is a “Warranted Superior” backsaw from the 50s or so. There’s nothing remarkable about it. It’s not mine (it belongs to someone in the family), but I’ve had it for a while because it was in bad need of a rehab. The teeth had been nearly worn off in places. Nasty. So, after refinishing the handle and redoing the teeth, it cuts about as well as you’d hope it to. Interestingly, it’s been a while since I did crosscut filing; most of my latest projects have revolved around different varieties of rip saws.

Unfortunately, this thing was on my project list for a couple of years. Now I can finally send it back to its owner.

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Winchester Saw: Finished

Dec 9

Posted by Brian in Finishing, Old Tools, Saws | No Comments

My Winchester No. 16 handsaw has been sitting around waiting for me to do something to it since time began. I’ve had this saw for nearly five years. When I finally decided to do something about it, it was back in March, when I discovered that it was a Winchester:

I didn’t know what to do with it at that point. It’s a mildly rare saw, so one option was to try to sell it for something useful, for example, a pile of Disston D-8s. But the handle was in crap condition, and it had the less-snazzy “Warranted Superior” medallion, so I decided to restore it and keep it as a user. I don’t know when I decided to do that, but it was a long time ago, and as such, I’ve had the blade sitting around, derusted and waxed, waiting for sharpening. I took the handle off, and procrastinated on the refinishing.

About three weeks ago, I decided to do something about it. I finished today:

The saw was filed to 6TPI. That’s pretty coarse for a crosscut saw, so I was originally going to make this a ripsaw to replace my beat-up D-7. However, the handle has that funny notch on the top that would make ripping uncomfortable with two hands, so I figured decided that this would, in fact, remain a crosscut saw. The rake angle is 15 degrees, with the fleam angle at 20 degrees. I had initially filed a 20-degree rake angle, but I screwed up pointing it (of course), so on my second try, I decided that since it was so coarse that I should make it a little more aggressive. It was probably a good idea; it does saw very efficiently. The cut is fairly clean for 6TPI.

I spent about a million years refinishing the handle. It was dented, nicked, and beat up. This photo also shows how the top horn was mangled:

The first thing I did (several months ago) was strip the original finish. At the same time, I cleaned the sawnuts:

And then it sat. And sat. And sat, until about three weeks ago. Even after stripping the original finish, it was still really uneven, so I sanded around the curved parts. For the flat parts, I just skimmed it with a smoothing plane. At this time, I also learned what the wood in the handle was for the first time–American Beech (fagus grandfolia). OK, well, that’s not a big surprise.

Then there were decisions. Should I stain it? With what? I finally settled on few thin coats of a “Colonial Maple” pigment stain. I used a washcoat beforehand. Though it would result in accented nicks and dents, it would even out the flat parts, and who’s going to try to hide the fact that this saw hasn’t been used, anyway?

Finally, I decided to use the same flat-sheen polyurethane that I used on the mallet as a protective top layer. I went from a thin coat to thicker coats, then back down to thin coats for the final one. Several coats were necessary, because the varnish would run down the surfaces that were vertical, depending on the way you held the handle. I did the first coats with the handle held upright, then the later ones held flat. A close-up of the finished handle:

I used a progression of 320 grit sandpaper, #0000 steel wool, 1500 grit sandpaper, and rottenstone, all lubricated with mineral oil, to rub out the finish. There’s still a scratch here and there from the coarse-grit paper (because polyurethane is tough), but overall, it looks nice, and it’s very smooth to the touch.

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Small tenon saw, Part 2

Oct 2

Posted by Brian in New Tools, Saws | No Comments

So the old ridiculous teeth were all filed off, and it was time to put on new teeth. On Thursday, I decided on 14 TPI (teeth per inch), put the saw along with a tooth guide in the saw vise, and set out to rock and roll.

It was not as easy to get the new teeth started as I would have hoped. I tried a small hacksaw at first. That didn’t work out, so I moved to a handsaw file. That wasn’t fine enough, so I finally dug out a set of hobbyist-grade needle files and found one that had sort of a knife-like edge. That worked, but it was slow, because that file sucked. It took forever to get the 140 little notches cut for the teeth, and my hand felt a little funky after doing it, but it was precise, so I was happy, and left it for a while.

On Sunday, I picked a rake angle of 20 degrees, and went to town shaping the teeth. Here’s what it looked like halfway through:

And close up…

After setting the teeth and a jointing, it was time to point the teeth. I chose 20 degrees for the fleam as well.

The result was far better than any crosscut sharpening I’d done before. (I don’t have a closeup, maybe on the next installment.) The best part, though, is the way the saw cuts–smoothly and quickly.

So now I have a workable small tenon saw. I don’t like the gent’s handle, and I do want to replace it with a closed-grip handle, but this is not an immediate need; I want to practice making tenons with it before going into further modifications. I’ll make the handle later.

I’m so happy with the way this has turned out that I’m considering buying a second saw for use as a ripsaw. It would only set me back another $10. Whee…

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Small tenon saw, Part 1

Sep 23

Posted by Brian in New Tools, Saws | No Comments

I’ve had the fantasy of making my own backsaw ever since I heard of someone else doing it. Unfortunately, I have an immediate need: A crosscut tenon saw for, well, cutting tenon shoulders. I do not have time to fool around forever, and I do not want to grind off any more of my current Jackson backsaw.

When I was in OSH the other day, though, I noticed that among the usual crud, there was a 10-inch Craftsman-brand “dovetail saw.” It featured the same general dimensions of the tenon saw I’d envisioned. In addition, the blade was moderately-sized–not as thick as a handsaw or the bigger backsaws, but not as thin as a dovetail saw is supposed to be.

I thought, “heh.” The teeth were ground in an absurd way; it was sort of a semicircular-type pattern. Plus, it had wavy set (on a 16 TPI saw!). Gee, thanks for trying, guys.

But it was only $10, and was purported to be made in the USA, so I thought, well, hmm, maybe I can make something of this, since it does have a blade and a back that I wouldn’t need to make and attach. So I bought one, then promptly went to town milling off the teeth with my saw jointer:

(“Fine, smooth finish cuts.” Yeah, sure, buddy.)

Well, at least the first stage seems to have gone fine. Next, I ought to cut new teeth. I’m thinking that I’d like somewhere around 14 TPI. Then I want to make a handle to replace that silly gent’s handle. I’d like to make the handle from beech or cherry. After today’s episode with beech, I’m not sure I want to mess with that so soon again (at least, as long as I do not have a scrub plane), but then again, I don’t know much about cherry’s durability, and these are not large parts that we’re talking about here. Eh, I don’t have to decide tonight.

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Ripsaw Revelations

Aug 30

Posted by Brian in Saws | No Comments

There was no way around it–I was not able to continue with the milling without a ripsaw. I rigged the saw vise to the workbench, then threw the blade from the old dogmeat 26″ Disston D-7 that I’d “cleaned up” (a few months ago) into that vise:

My expectations were kind of low. Though waxed and now rust-free, this blade is badly pitted and slightly bent at one place. It had been a chore just to get the stupid handle off. And the 7 TPI-pattern teeth were a horror story–badly deformed, uneven sizes, previously filed to crosscut profile, fairly wide set… you name it. The pic above is after jointing. Here’s a fuzzy close-up that should give you an idea of how crappy the teeth were:

Using a zero-degree rake angle, I worked my way across the saw, taking just one stroke at a time. I had to make four passes to get all of teeth even, so that’s four strokes per tooth. I ended up with this:

I left the set as it was; the filing had eased it a little.

This sharpening session was much easier than my earlier experiences. There were considerable improvements: I have the workbench now, so the vise was much more secure. The location afforded a lot more light; it was much easier to see the tips of the teeth. And it was much more comfortable to work at that height instead of the previous ridiculous situation of sitting on the floor.

I still had my doubts because the saw wasn’t in great shape to begin with. Of course, this was on purpose, because I wasn’t going to mess up one of my good saws on my first try at rip filing. But whenever you get a new toy, you want to play with it, so I put the handle back on, clamped a douglas fir 2×4 to the bench, and tried it out.

Gee-hose-a-phat. That thing split apart the 2×4 like it was nothing at all. Disston ads used to say stuff like “Zing!” And that’s exactly how it felt.

Unbelievable. Hmm. I have two other ripsaws waiting over there… a monster Disston No. 7, and the Winchester that I described a long time ago. Did I mention that those two are straight and have no pitting? Oooooooh.

[edit: Actually, the Winchester is a crosscut saw.]

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First complete saw

May 23

Posted by Brian in Old Tools, Saws | No Comments

Last week, I finally finished off that Jackson backsaw that I’d been working on since before the dawn of history. Here’s what it looks like when all was said and done:

Skipping back a few entries, this is what it looked like before I did any work:

As you may recall from the last episode, I messed up badly and had to reshape the teeth before I got to the final stage of pointing (sharpening/filing the fleam). But finally I got to print out my tricky-dicky PostScript fleam guide and use it properly. Here’s how it looks in use:

All you do is align the file over each line and take a few strokes. This picture was shot after the first half of the teeth were done, so you can see how every other tooth is a little shorter. It evened out very nicely, just as it was supposed to, and when viewed end-on, the “valley” that you’re supposed to see between a crosscut saw’s teeth was there. Fantastic.

The tip of this saw isn’t in good shape. There’s a kink in it, and the teeth are especially uneven there. Because it’s only about an inch and a half of steel, I’m considering taking the moderately drastic measure of hacking off the tip. I likely already would have, except that I don’t have a machinist’s vise yet.

I didn’t do anything to the handle of this saw, either. Unfortunately, it’s shot; it’s soft almost all the way through, making it hard for the sawnuts to get a grip. The sawnuts are also in bad shape. So I just put it back together so that it wouldn’t be too loose. There’s no point in fussing with it any more; if I want to improve the handle, I’ll need to make a new one. (This is not a bad idea, because I like the shape of the handle and have this fantasy of eventually making my own saws.)

Well, so much for the saw’s looks. A more important question is, “How does it cut?” I’m happy to report that it’s great. Due to its somewhat aggressive rake angle and the relatively low number of teeth per inch, there is moderate tearout, but it saws quickly and with very little effort.

For some reason, I don’t particularly expect to use this saw much. It should be fine for cutting smaller boards down to size in a miter box, and for cutting down the shoulders of tenons, but it’s too small for large boards, and because it’s a crosscut saw, it’s useless for sawing down the cheeks or anything else that’s a rip operation. That’s fine, though. My next two saw projects really ought to be full rip and crosscut handsaws.

I’m a little relieved that my two candidates for those two saws are in much, much better shape than this thing when it started out…

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