Monthly Archives: February 2010

Frankensaw; Saw Sharpening Guides

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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.

Update: I now recommend that you use the versions that are on the Plans and Guides page rather than the following, but I’m not going to remove these any time soon.

Here are PDF versions for:

  • 10 degree fleam (fleam10)
  • 15 degree fleam (fleam15)
  • 20 degree fleam (fleam20) (whoops, need to regenerate that sometime)

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.

My Sloped Gullets

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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.

New Dog Holes, More Milled Wood

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I’ve been doing a lot of milling and resawing lately. My prototype bookshelf will use the following pieces of yellow-poplar that I dimensioned:

Yeah, I know, it’s not too exciting, it’s just some wood.

This stuff was quite cupped when I started out, so I had to do a lot of work with the scrub plane to get it flat. To do so, I decided to put a second row of dog holes in the workbench so that it would be easier to plane across the grain:

To use them, just add some dogs in the appropriate holes, as shown here by this evil piece of beech:

It’s been working well so far. I’m considering adding one more at the corner so that it really doesn’t have any room to move around, but it’s not important right now.

Why, you ask, is that board evil? Well, it’s from a piece of 8/4 stock, about 11″ wide. To get to the point of resawing it, I had to flatten one face. No problem, except when you don’t hammer in the scrub plane wedge enough. When that happens, the blade can pop out when you’re doing hard work. The overall consequence, then, is minor carnage. Ouch. I lost a few days of shop time from that.

In any case, this board is for another project that I haven’t talked about yet. I’ll post more details on it later.

Frame Saw: Resawing panels, repairs

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One of the projects I’m starting now is a small bookshelf prototype that I’ll use to guide my way through building later versions. I’m in the process of milling the wood, and to make efficient use of the wood, I decided to resaw 4/4 boards so that I can use one slice for the sides and shelves, and the other slice for a panel in the rear of the bookshelf.

So it’s the first real-life use of my frame saw. It does fairly well; here’s a roughly 1/4″ slice that came off one board (this is Yellow-poplar/Liriodendron tulipifera):

The upper left looks slightly ugly in this shot, but it’s actually just two passes of a plane from totally flush. The result is actually quite good–very flat, no wandering of the saw. I seem to run into difficulty at the end of of the board, and I’m still trying to figure out ways to make that easier. Unfortunately, what didn’t help was the tension on my frame saw being too great for the hardware that I made to hold the blade in place, causing it to tear apart on one side:

Yikes. Well, okay, so I just chopped it off and remade the piece. I think this part is a little weak because of the recesses I filed for the itty bitty screws that I no longer use. I’m still not entirely happy with the arrangement, but if it holds, I’ll change my attitude.

Speaking of attitude, mine towards my front vise has been one of complete irritation for the past several months. I’ve had the endcaps held on at the very tip with screw inserts in the center with a machine screw to hold the whole thing in. Unfortunately, the insert kept coming out (because inserts don’t work well when inserted parallel to the grain, duh), the cap would come loose, and the handle would fall out of the vise. Of course, it would always fall out at an appropriately inconvenient time.

This was happening on only one side of the vise, and I finally fixed it for good today by relocating the insert to the side of the handle instead of the tip (you can see the hole in the tip at the right where the screw used to be):

I suppose that it’s fixed “for good” until this happens to the other end of the handle and I have to do the same thing there. Sigh. Why it took me so long to fix this is beyond me.