Straightening saws

[beech1948]

I'm looking for advice about straightening saws.

I have acquired in recent years around a dozen Disstons. My problem saws are a 26" 5pt rip and a 26" 6.5pt rip. Both have a slight kink about 9" up from the end. I have a few others which have more difficult kinks but I have to start somewhere. I have a couple of saws so old and worn out that their next use will be to be cut up as scrapers so I have something to practice on.

I have access to a 20lb anvil, an oak tree stump cut level and levelled and have a selection of ball pein hammers from 4oz to 2.5lb in 4oz steps...and a few others as well but I am not a collector..no sir.

I have some experience of working metal, a good feel for it as well I just need the confidence to have a go.

Anyone done this or can recommend a video or book.

 

[Argus]

A knotty problem.

Often, very slight bends make little if any difference to sawing provided that the saw is sharp and the set is even and without bias.
Still, it's a pain if a good saw has a kink; even if it is minimal, you're always conscious of it..

Paul Sellers has a video on the subject, even if it confines itself to short tenon saws.

You can judge for yourself:

https://www.youtube.com/watch?v=tzc4tQ5CRxk

Good luck.

 

[Trafalgar]

Here you go:

http://www.wkfinetools.com/contrib/bSma ... Blade1.asp

 

[beech1948]

Thanks for the wkfinetools links . I had already read those but a second read helped a bit.

I am going down to see a blacksmith tomorrow to talk about how to stretch/compress metal when cold and maybe practice a bit.

I also found this book from the early 1900's. "How to Straighten and Gum saws" Not had time to read it yet but early skimming shows promise.

And a Paul Sellers Youtube video https://www.youtube.com/watch?v=tzc4tQ5CRxk

And here http://www.carbideprocessors.com/pages/saw-blades/hammering-saw-blades.html

and http://www.fhwa.dot.gov/environment...cations/fs_publications/pdf/pdf77712508hi.pdf

and I have ordered this http://www.forgottenbooks.com/books/The_Sawyer_and_Filers_Friend_1000787036

What I am finding is that there is little real knowledge available to me or it is too far away and difficult to get to. I wonder how I might talk to Bob Smalser about this. My other source is an old gent now in his eighties who used to work for Tyzack in his youth who has been asked to get in touch and he is only 55 miles away.

First real practise was last weekend. Much to learn eg a saw is never completely straight. Next practice is this coming weekend after I take possession of a set of planishing hammers and a hammer with a blunt chisel end and a convex flatted end.

If anyone else is interested then let me know and I will document what I am learning.

 

[profchris]

I bought a boot sale handsaw with a distinct swerve to it, and found a detailed post here showing the pattern of hammer strokes needed to straighten it. But, the post said to begin by flexing the saw as far as possible in either direction first (holding the blade, not the handle). So I did that and now have a pretty much straight saw, no hammering.

Worth trying. Though not with a backsaw.

I got the bend to nearly 180 degrees before my nerve and wrists failed. The pics showed nearer 270.

 

[Trafalgar]

I think straightening saws is like learning surgery -- you're going to kill or maim a patient or two until you get the hang of it.

Appreciate the link to "Forgotten Books." What a great resource.

You might email Wiktor Kuk at WK Fine Tools for Bob's email.

 

[Corneel]

Certainly interested. I have a few candidates myself.

 

[Mike.S]

If anyone else is interested then let me know and I will document what I am learning.

Yes please.

I knocked my thin blade DT saw off the bench and it landed on it's teeth at the toe - putting a slight bend/kink in the blade. Grip with pliers and bend back; put in a vice with shims to bend back; or hammer; or....? So, please do share your experience.

 

[Trafalgar]

I like the way Bob Smalser put it -- "these are not low-ordered skills..." or words to that effect. I think it's quite possible to think one has put a saw right and not be an experienced enough sawyer to know that one has in fact ruined it. This isn't aimed at any particular post/participant in the thread. It's hard to know the difference if hand saws aren't being used for hours a day, day in and day out, year after year (and this certainly doesn't apply to me).

 

[AndyT]

and I have ordered this http://www.forgottenbooks.com/books/The_Sawyer_and_Filers_Friend_1000787036

Appreciate the link to "Forgotten Books." What a great resource.

It's a bit off-topic, but as far as I can see, the "Forgotten Books" site may be handy as a way of discovering books but they are only pointing you at resources that have already been scanned and put online by others. In my experience, anything that I have seen on there that I might want to read is already available elsewhere. A simple way to check is to put the title and author into the search box at the Open Library which will then give you links to online editions, published editions (including POD) and library holdings by distance from you (using WorldCat).

In this case, the whole brief work is available to read online or download in a choice of formats to read on screen or print at the Internet Archive here:

https://archive.org/details/sawyerfilersfrie00mine

 

[JohnPW]

and I have ordered this http://www.forgottenbooks.com/books/The_Sawyer_and_Filers_Friend_1000787036

Appreciate the link to "Forgotten Books." What a great resource.

It's a bit off-topic, but as far as I can see, the "Forgotten Books" site may be handy as a way of discovering books but they are only pointing you at resources that have already been scanned and put online by others. In my experience, anything that I have seen on there that I might want to read is already available elsewhere. A simple way to check is to put the title and author into the search box at the Open Library which will then give you links to online editions, published editions (including POD) and library holdings by distance from you (using WorldCat).

In this case, the whole brief work is available to read online or download in a choice of formats to read on screen or print at the Internet Archive here:

https://archive.org/details/sawyerfilersfrie00mine

Still off-topic (sorry but this really annoys me!) that company is trying to claim copyright on out of copyright books!
From their FAQ:

Can I have permission to reproduce part of one of your books?

We have a flat royalty-free rate of $50 per page for printing or electronically distributing any of our content for non-personal and non-educational purposes. For more information please contact us. If you only intend to quote from a book, and do not intend to use any of our pages as formatted, then you may do so free of charge if you believe the original of the book in question to be public-domain.


Can I have permission to translate one of your books?

Our editions of each book are copyright to Forgotten Books, but most of the originals are public-domain. If you can verify for yourself that the original is public domain then there is no permission required for a translation.


Are your books in the public domain?

None of our books or eBooks are in the public domain, all are copyright to Forgotten Books. Many of the originals may be public-domain, but our own editions are copyrighted.

So I urge everyone not to visit the site, and not to use it any further, even if it's just to browse titles!

 

[Trafalgar]

They are limiting access but the flip-side is that I'm seeing titles there I've not seen elsewhere. I probably just need to look harder.

 

[bugbear]

They are limiting access but the flip-side is that I'm seeing titles there I've not seen elsewhere. I probably just need to look harder.

See AndyT's post earlier for useful advice.

BugBear

 

[beech1948]

Just a few comments from my Saturday am practice with a blacksmith/farrier.

1) its really odd walking down the road with literally a bag full of hammers and two saws without handles. Handles removed because they get in the way.

2) First problem. Find the source point of the damage. I used two straight edges; one on either side of the blade. Tried to find the length of the curve, the first point of curvature because the length from the handle end to the damage must be the original straight blade. Difficulty is to do this in the x-y direction simultaneously with the z direction and also to find that the slight 2d tapering of the blade has an impact. This tapering is over both blade height and length and differs strongly from heel to toe.

3) Learned that finding the changes in straightness/curves/kinks is about several things. 1) Visual inspection tells you where approximately the damage is and its a good idea to mark this approx with chalk. 2) The straight edge tells you exactly where the bumps/lumps/kinks/hollows and bends are. Need to mark these with a different coloured chalk.

This might be my IT background coming out but I found a need to create a lexicon of chalk shapes to tell me what was happening. So A: A large ellipse of white chalk to mark rough area. B: A pattern of blue chalk slashes to show where hollows were C: A pattern of green chalk to show the extent of bumps/lumps D; Red chalk for everything else.
My blade had a 200mm hollow with 2 bumps of about 20mm and a small kink on the blade edge about 30mm high and 40mmm long.

Gerald, my blacksmith friend at this point burst out laughing at what he saw as an absurd level of detail. Some strong "banter" was exchanged which resulted in us agreeing to disagree about the level of detail. His next source of amusement was when I produced an 8oz ball pein hammer and he was right to laugh as I ended up using my 2lb hammer on a practice saw.

Lesson from Gerald was that no substitute for weight with hammers. Followed by its not the weight of the hammer but the power behind the blow. He showed me how to stretch a piece of metal from a flat into a circle using only a hammer and nothing else. Took me 1.5 hours of bashing his anvil to learn this. Its about feel and control of landing weight of the hammer. Its also about use of the ball and the pein in a ratio of about 2:6...or stretch -consolidate stretch - consolidate.

Back to my saw. Tackled the kink first. Five blows from the pein or flat face of the hammer onto the upturned face of the kink. Flattened it 80%. Bear in mind that you are also destroying the set of the teeth as these get flattened. A couple of blows of the ball stretched the kink back towards flat: followed by about 5-6 blows from a planishing hammer against the upturned kink. Result not perfect but about 95% of the way there.

Two bumps dealt with the same way. Pein used to flatten and tension. Ball used to add a little extra tension. Bumps removed but left a pattern of small shallow hollows.

Large ellipse was tackled by first bending the blade around about 270 degrees in both directions which removed a small amount of the curve. Next up was my chisel hammer....its about a 1.5lb hammer with a blunt chisel head and a flat pein head....I don't know its real name. I placed a pattern of 30 to 40 blows at low power across the surface of the upper side to the direction of bend. These blows were in a hatching pattern with the hatches at approx 90 degrees to each other. Result was removal of most of the curves and hollow .

I realised that the reason why not all of the hollow had gone was that I had not been hitting the steel hard enough so a second round of "hatching" shaped blows was needed and yes a third round also in a few places. Between each hammering I had to use the straight edges to see where I was at.

This took about 2 hours. Gerald then put the saw on top of his forge to let it warm up to about 150 degrees to relax the blade.

Result. Blade was much improved. Tooth line was looking straight but in reality had two small curves of about 1mm to 2 mm along its length.

Blade was sharpened, set and then tried on a piece of 2x4 softwood and produced a good cut over about 5 ft. So the first experiment was successful.

Learning was that a saw does not need to be millimetrically straight but does still work well when the blemishes are within 1 mm of straight.

Learning was also that the blade needs to be clean and shiny before trying this. I used an electrolysis bath for 24hrs and then cleaned off the residue with 800 grit wet and dry and oil.

Next time I will try to take pictures.

Total time taken 3 hrs

 

[AndyT]

Thanks for sharing that - fascinating evidence of how skilled the old Sheffield guys were. And a difficult skill to learn without someone to show you how.

I think that for most of us, the answer to what to do about a kinked saw will remain "Buy another saw" - which is not as much fun as acquiring a new skill and putting the work into it.

 

[Trafalgar]

They are limiting access but the flip-side is that I'm seeing titles there I've not seen elsewhere. I probably just need to look harder.

See AndyT's post earlier for useful advice.

BugBear

I see it... thanks.