Back saw blade depth in spine?

[Cornersruns]

Having just bought a couple of old back saws for restoring and practicing sharpening I am confused, nothing new, about how far into the spine the blade should sit.

On one of Paul Sellers videos he shows thumping the spine on the workbench, to correct bend in the blade, until you hear a solid thump. Implying to me that the blade is touching the top of the bend in the spine, is the blade cannot go any further
Some of the threads on here seem to say that the blade only needs to be about 1/4 inch into the spine and that gentle taps will adjust the tension to straighten the blade.
Can anyone confirm which is correct, a pointer to further reading would be good as well. My thinking is that the blade should not hit the internal wall of the fold as you cannot adjust any further as you have hit a natural depth stop.

At the heel it looks like most saw blades will not fully insert into the spine as the handle provides a depth stop. But the toe has no stop until it hits the internal fold of the spine.

Thanks

 

[Cheshirechappie]

About 1/4" is correct. More reading here;

http://www.badaxetoolworks.com/retension-a-backsaw.php

 

[D_W]

The short answer is that you put the spine at the depth that keeps the saw straight and that's about it.

Two types of spines - folded and slotted. Slotted in theory should be pretty even, but folded apply pressure and were probably bent in a brake before the days of slotting and gluing in saw plates (some slotted aren't glued, though).

If you're making saws, you generally shoot for about halfway into a folded spine to leave adjustment room. If you're adjusting an older saw, you are just trying to adjust to straight and every other goal is secondary or lower.

 

[MikeG.]

Having just bought a couple of old back saws........

Because I am only pretty certain, not absolutely certain, that "backsaw" is an American term I am only going to threaten you with the stocks rather than impose an immediate sentence of flogging. The fight against the creeping Americanisation of our woodworking language because of Youtube is a fight to the death...... :lol: :lol:

 

[Cornersruns]

Profuse grovelling for such a heinous crime, I shall immediately self flagellate with Holly or thorn.

 

[D_W]

Having just bought a couple of old back saws........

Because I am only pretty certain, not absolutely certain, that "backsaw" is an American term I am only going to threaten you with the stocks rather than impose an immediate sentence of flogging. The fight against the creeping Americanisation of our woodworking language because of Youtube is a fight to the death...... :lol: :lol:

Don't forget that thanks to ebay, we will soon have all of your tools, too.

 

[MikeG.]

Profuse grovelling for such a heinous crime, I shall immediately self flagellate with Holly or thorn.

I like your attitude. Just a tip with holly....the leaves further up the tree are less spikey.

 

[AndyT]

Because I am only pretty certain, not absolutely certain, that "backsaw" is an American term I am only going to threaten you with the stocks rather than impose an immediate sentence of flogging. The fight against the creeping Americanisation of our woodworking language because of Youtube is a fight to the death...... :lol: :lol:

Being the sort of person who prefers facts to guesswork, I've been checking up and I think, Mike, that you mostly but not entirely right on this one.

The OED doesn't include "backsaw" as a head word and only gives one dated quotation for the use of the two word phrase "back saw" - from Edward H. Knight · The practical dictionary of mechanics · 1st edition, 1874–1884 (4 vols.), published by Cassell in London.

But although the cited work was published in England, it's originally an American work. Kight emigrated from England to the US in 1845.

Google's Ngram facility lets you chart the appearance of any word over time, using a large corpus of scanned books. If you search for backsaw, back saw and back-saw, it seems to show earlier references but these are all for sentences that end with the word "back" followed by new ones starting with "saw".

Sifting through the dross, Google doesn't come up with an earlier date for backsaw as a word, and almost all of its sources are American - though I think their corpus is biased towards US publications anyway.

So yes, backsaw as a single word was an American coinage.

I've looked in some UK publications where you might expect to find it. As far as I can see, it's not in Moxon or Nicholson. Holtzapffel in 1846 refers to "Parallel saws with backs" where the word might have been useful.

Early catalogues mostly just list "saws" then go on to list tenon saws, dovetail saws etc.

The price list in the 4th edition of the Sheffield List (between 1855 and 1860) does have a section headed "Iron and Brass Back Saws" but this could just be a wordy description rather than a regular phrase.

So yes, on the whole, it's an American usage.

BUT - I have found a definite usage from 1960, in the words of the impeccably English firm of Spear and Jackson. It's in their publication celebrating 200 years of saw making, "The Story of the Saw". You can read the whole thing here

https://archive.org/details/SpearJackso ... ch/backsaw

The quote is: Tenon saws and their derivatives have short, rectangular, thin blades with teeth slightly set, and strengthened by a stiff metal strip along the back edge. This prevents them from entirely penetrating the wood. (From which they earn the name back saws.)

I think that's reasonable evidence that, at least among experts who talked a lot about saws, the general term had begun to be used on this side of the Atlantic quite some time before YouTube came along.

And after all, some of the tools that those Yanks came up with are pretty good, so I don't think it's too bad a thing if we also import some of their words, where we don't already have a useful category term of our own.

 

[kwigly]

Cornersruns, Andy seems to be implying that instead of holly or thorn, you could use foam rope or a feather duster ?

 

[Cornersruns]

Cornersruns, Andy seems to be implying that instead of holly or thorn, you could use foam rope or a feather duster ?

But that is not the british way old boy. Nanny would never have used such a lightweight form of punishment, reduces the enjoyment somewhat.

Anyway Spear & Jackson using it in the 60's does not make it right, there were too many americanisms starting to come over by then anyway.

 

[Cheshirechappie]

As I quite enjoy these diversions into arcane trivia, I too have doing a bit of research, though my feeble efforts in no way compare with Andy's.

Holtzappfel does refer to "back-saws" with the hyphen (p714), though as Andy stated, he does seem to prefer "parallel saws with backs".

George Ellis ("Modern Practical Joinery" pub. 1902) refers to "Tenon" and "Dovetail" saws (interestingly, not, as far as I can see, "Carcase" or "Sash" saws) for the most part, but does mention on page 10 "The Tenon Saw, or as it is sometimes termed, the Back Saw" - two separate words and no hyphen.

RCF Tools catalogue, Summer 1976, refers to "Back Saws" in the index, but doesn't mention them in the main body of the catalogue, referring instead to "Tenon" and "Dovetail" saws.

You may have a point, Mike!

 

[AndyT]

Thanks for that, CC.

I should also like to add that Simon Barley, who probably knows more about old saws than anyone else, uses the category "backsaw" throughout his "British Saws and Saw Makers" to distinguish saws with backs (of all sizes) from saws without. It would have been impractical for him not to do so.

So do the erudite contributors to http://www.backsaw.net - no surprise there!

 

[Cornersruns]

So when does a tenon saw become a dovetail saw, is it tpi/ppi or length of blade ?
Don't want to make another faux Pas

 

[Cheshirechappie]

By strange coincidence, we had a thread on that very subject a few weeks ago;

backed-hand-saw-sizes-t121600.html