Thread: Disston Backsaw

Colin, the handle indicates post-WW2, but you may not be able to pin it down much more than that!

If the distance from tooth line to spine is deeper at the back than the front, I doubt it is factory-original on a saw of this vintage. It could be due to one of two things. The spine may not be sitting straight with reference to the back of the saw (i.e., it is tapped down more at the front than the back). If that isn't the source, it has most likely arrived at that shape over time after repeated sharpenings.

Backsaws from a much older era than your saw were made with blades shaped like this. "Canted" seems to be the agreed term, to differeniate it from tapering, which usually means that the blades are ground so that they are thinner at the top than at the tooth line. This was done almost exclusively on large hand saws, and only a very few back saws were tapered, but it can be very confusing to use the same term for two entirely different things.

You will come across many more backsaws with canted blades than were ever made that way. I think it's mostly 'acccidental' due to the fact that the teeth at the toe of the saw cop the most wear & abuse (they are usually first to 'discover' a nail, for e.g., & may even break out). Because of this, they often need a bit more jointing than the teeth on the heel, in order to make a visible flat when preparing to sharpen. Over many sharpenings, the tooth line slowly angles up toward the spine.

I like the canted shape, and have made quite a few small saws with canted blades for that reason alone. It's possible that a few people deliberately worked on their saws to produce a canted shape, though most of us would find it a bit hard to file away several years' worth of metal just for appearance's sake, I imagine!

In any case, you should have a perfectly good little user, there. A clean-up & good sharpen & set would be the first step. I'd get to work on that handle a bit, too, if it were mine (or replace it altogether, more likely! ), but it won't stop it from doing a good job for you......

Cheers,

I've seen a cabinet maker hit the toe end of his backsaw when cutting half blind dovetail sockets. After cutting to the line on the drawer front, the drawer front is then placed flat on the bench, kerfs uppermost and towards you. The saw is then inserted into the kerf, following the angle of the cut and the back of the saw struck to drive the toe into the wood severing the fibres. Subsequent chiseling is easier.

This may be one reason old backsaws often have more meat at the back than the front.

Paul

Difficult to tell from the photo, but the spine does seem rather high suggesting that it has lifted.

Originally Posted by homesy135

I've seen a cabinet maker hit the toe end of his backsaw when cutting half blind dovetail sockets.......

Paul, I guess it was a means to an end, and when time is money, you want the job done as quickly as posible, I suppose. Perhaps a better technique (from the saw's point of view, at least) is to use a sharpened scraper blade instead of a saw. Tage Frid advocated this method in one of his early books.

Another technique I can't stomach is to grossly overcut the sides, so that the waste can be chiselled out easily. Looks really sloppy to me, but then I'm not trying to feed a family on the proceeds of my cabinet-making...

Cheers,

Thanks for all the comments, and thanks to Ian on the correct terminology to use.

Post war is waht it seems to be - according to Online Reference of Disston Saws -- The Medallions the medallion makes it post 1947, which while it may not have been the golden years is still a whole lot better than much of the junk being made now.

I'll try to find a little time to remove the handle so that I can see if the back is standing proud of the blade. Either way, it's still usable as it is although I can see that I'm going to have to get set up to (and learn how to) sharpen saws soon.

Originally Posted by Colin62

....I'll try to find a little time to remove the handle so that I can see if the back is standing proud of the blade....

Colin - no need to remove the handle unless you really want to. If the spine is straight & sitting fully in the groove cut out for it in the handle, and the blade looks straight when you sight along the tooth line, you can simply assume it's all ok, for now. If the handle comes off easily (should do if the bolts are brass), it will make it easier to clean both blade & handle. Spines should fit firmly, but come off with a bit of gentle tapping. Before you do that, check how deeply the blade is sitting in the spine at the handle end. That's most likely to be where it was seated originally, and when you replace it, try to maintain that distance from front to back.

There are different schools of thought about how deep a blade should be seated in its spine. I've tried to figure out logical reasons why it should be in any particular position, but can't come up with anything truly convincing. For spines made from solid brass, with accurately machined blade slots, I can't see any reason why the blade shouldn't be fully seated in the slot. The spines on old saws are all made by folding a strip of steel or brass, and the blades are usually not fully seated from new, so there may be some good reason for that, but I don't know what it is. P'raps someone could enlighten me?

Originally Posted by Colin62

....I can see that I'm going to have to get set up to (and learn how to) sharpen saws soon.

Sooner or later, it comes to that. Unless you can find someone local who still sharpens saws properly, it's a DIY job.

It's not rocket science, just a matter of perseverence until you get good enough at it. From your original picture, your saw seems to have a fine pitch, and it's of the size that should make a prety good dovetail saw, so I would suggest you file it as a ripsaw, which is easier for a newbie sharpener to do well. There are those who advocate you sharpen any saw finer than about 15tpi as rip, because it's easier to do and it makes little difference to the efficiency of the saw. When dovetailing, most cuts are with the grain, more or less, anyway....

If you read this, it will help, I think. Once you actually get down to doing the job, it will make more sense.
Cheers,

Originally Posted by IanW

Colin - no need to remove the handle unless you really want to. If the spine is straight & sitting fully in the groove cut out for it in the handle, and the blade looks straight when you sight along the tooth line, you can simply assume it's all ok, for now. If the handle comes off easily (should do if the bolts are brass), it will make it easier to clean both blade & handle. Spines should fit firmly, but come off with a bit of gentle tapping. Before you do that, check how deeply the blade is sitting in the spine at the handle end. That's most likely to be where it was seated originally, and when you replace it, try to maintain that distance from front to back.

I took the handle off (simple enough), and checked how far into the spine the blade was fitted. At the toe end of the saw, the blade is seated all the way into the spine, and at the handle the blade can still go about 12mm into the spine. If I measure for the bottom of the blade to the top of the spine, it's 78mm at the toe and 90mm at the handle, so it look as if the blade is still the original shape. It looks (to the eye) as if the etching lines up with the teeth too, so Im thinking that the most likely scenario is that the spine has just been tapped further over the blade at the tip.

Originally Posted by IanW

Sooner or later, it comes to that. Unless you can find someone local who still sharpens saws properly, it's a DIY job.

It's not rocket science, just a matter of perseverence until you get good enough at it. From your original picture, your saw seems to have a fine pitch, and it's of the size that should make a prety good dovetail saw, so I would suggest you file it as a ripsaw, which is easier for a newbie sharpener to do well. There are those who advocate you sharpen any saw finer than about 15tpi as rip, because it's easier to do and it makes little difference to the efficiency of the saw. When dovetailing, most cuts are with the grain, more or less, anyway....

If you read this, it will help, I think. Once you actually get down to doing the job, it will make more sense.
Cheers,

I bought it hoping to be able to use it for dovetail work (not that I do a lot of dovetail work ), so what you suggest is most likely what I'll do. Thanks for the advice on sharpening (and the link - takes away a lot of the mystery). I'll also ask around at the woodworkers' guild meeting next week and see if I can find someone who has the time and patience to help me get started - always easier when you have someone there in person.

Originally Posted by Colin62

......I'll also ask around at the woodworkers' guild meeting next week and see if I can find someone who has the time and patience to help me get started - always easier when you have someone there in person.

Indeed - a bit of guidance at the start can save you a lot of time and trouble. You're launched on a great journey - having good saws that do their job well can make your woodworking so much more enjoyable, not to mentionmore accurate!
Enjoy the ride!
Cheers,