cutting new teeth in a saw

[mickthetree]

Hi all

I have just acquired a box full of old tools. Some panel saws, some chisels, lots of old files and a tenon saw.

The saw has a bow in it around the centre of the blade and the handle needs reattaching.

The blade also has an arc upwards in the centre if looking from the side and the teeth are all different heights.

I thought I might use it to learn how to sharpen a saw before I buy a good one, but I guess I will need to take out the convex first by flattening. This will leave it needing new teeth cut.

I have seen a raft of sites on sharpening, all the jigs, marking guides etc, but no one seems to mention cutting new teeth from scratch other than giving it to a saw doctor. I don't think this saw is worth paying someone to do that on as it has the bow in the blade, so how can I cut new teeth myself?

Do I just use the files I have been given? or will that knacker them out? (if they are still any good in the first place)

Any suggestions greatly appreciated.

Paul

 

[Racers]

Hi,

Have a look ar bugbear's website http://www.geocities.com/plybench/saw_sharpen.html he has templates you can print out of different tooth pitches. File it straight select a template glue on to the saw with a glue stick, then start filing, I made several light passes just one stroke at a time so I could correct any un-even teeth, and I soon had a sharp saw. Do you have a saw set? you will need it to set the teeth.

Pete

 

[bugbear]

Thanks for the plug, Pete!

Any file can be used, but saws are hard - retoothing will probably take a file from usable to useless, so be prepared for that.

You're also doing a difficult saw - a crosscut back saw, which has small teeth and fleam is amongst the hardest to do well.

I do recommend reading most of my site (I would, wouldn't I!), and at least one of the blow-by-blow sites that I link to.

Oh yeah - I know you'll be keen to get on with sharpening after you've removed the teeth, but that would be the BEST EVER time to clean and polish the blade - it's the teeth that make cleaning up a saw tricky.

BugBear

 

[mickthetree]

Hi guys

Yes, I've read bugbears site "cover to cover" as it were and most of the sites you link too ;-)

There are lots of files in the box ranging from huge to very fine indeed. 3 or 4 in the size I need I think.

I don't have a saw set yet, but was going to pick one up off flea bay.

Well I may as well give it a go. The blade and back (steel I think) have been blackened at some point so its not the prettiest thing, but good for practice I think.

I can understand why a good saw costs what it does. Lots of effort involved and I think doing this will only improve my admiration for saw makers.

Well now I know its possible I'll have a go. I take some snaps as I go to let you know how I get on.

All the best

Paul

 

[woodbloke]

I tried cutting new teeth on a totaly flat crosscut tenon saw blade, no sign of the old gullet whatsoever. I found it just about impossible to file a regular pattern tooth profile...but I didn't wade through BB's stuff so I probably missed something - Rob

 

[pedder]

Hi Rob,

when I retooth a crosscut saw I start filing all teeth from one side. When they are all uniform in size and rake I add the fleam.

Hi Paul,

You wrote:

The blade also has an arc upwards in the centre if looking from the side and the teeth are all different heights.

Do you mean the breasting of the blade? You want that to stay on a hand saw.

breasting: http://www.disstonianinstitute.com/glossary.html (scroll down)

Cheers Pedder

 

[lurker]

You can also use a hacksaw blade (with the requisit number of teeth) as a template to start the new teeth off

 

[woodbloke]

Hi Rob,

when I retooth a crosscut saw I start filing all teeth from one side. When they are all uniform in size and rake I add the fleam.


Cheers Pedder

...and that was my problem, getting them all a uniform shape. I gave up in the end and lobbed it in the bin (it was only a tatty old car booter) - Rob

 

[Racers]

Hi,

I did only one stroke at a time, so I could tell by looking at the flats between the teeth it they where un-even and I could adjust them before it got to be a big problem. You need to be able to put the same presure on each stroke to maintain even teeth, its a case of getting into the "zone" and not stopping for anything untill you get to the end of the saw even if your hands are cramping up .


Pete

 

[Harbo]

I have tried a few times on an old saw (14TPI) using Bugbear's templates and tried the hacksaw template method but not happy with the results.

Intending to have it recut by a saw doctor as if I continue there wont be much saw left!

Rod

 

[bugbear]

Hi Rob,

when I retooth a crosscut saw I start filing all teeth from one side. When they are all uniform in size and rake I add the fleam.


Cheers Pedder

...and that was my problem, getting them all a uniform shape. I gave up in the end and lobbed it in the bin (it was only a tatty old car booter) - Rob

If the problem was shape (not size), I suspect it was variations in rake angle that cause the problem - Jigs and/or guides can help here (they certainly help me).

BugBear

 

[bugbear]

I have tried a few times on an old saw (14TPI) using Bugbear's templates and tried the hacksaw template method but not happy with the results.

What was wrong - tooth shape, tooth spacing, didn't go fast enough or "other" ?

BugBear (who remembers struggling on his first attempts)

 

[pedder]

...and that was my problem, getting them all a uniform shape.

Hi Rob,

it is not that difficult but you need a little practise.

I got much better, when I replaced the paper tooth patterns with old saws.

- For me it is essantial to have equal gaps from the first stroke. After the first pass I look at this. If the gaps are unequal, I'll file the hole saw flat again.

- Counting the strokes per tooth helps. Only 2-3 strokes per time. Try to give the same power an length to each stroke of one pass.

- File all teeth in one pass. That helps to give every tooth the same amount of power.

For Me: Retoothing is simpler on smaler saws.

Cheers
Pedder

 

[Harbo]

I just could not achieve a regular even patten - even using the hacksaw blades. I used a pair of blades - one each side and clamped on. In theory sounded like a good fail proof method - but in practice, did not work out?
Perhaps it's my eyesight, though I used a 5x manifying lamp?

Keep meaning to try again on some scrap sheet metal as I cannot risk attempting to try again on the saw! Also the blades wear out the files too!

Rod

 

[Peter T]

I got some old brass backed saws off e bay that needed some attention. I decided to use one as a guinea pig and tried re-cutting the teeth by hand.

This was a complete disaster!!

So, since I have access to CNC laser cutting equipment I decided to take a 21st century approach and laser cut the teeth. I really excelled myself when I decided to write a CNC program that would progressively change the tooth pitch from 15 at the toe to 10 at the heel

The laser cutting bit was a doddle but when I came to file the teeth I found that the laser cutting had micro-hardened the cut edges to a file destroying level.

Back to the hand filing

 

[matthewwh]

The convexity in the toothed edge is intentional, it is called breasting (ooer missus!) and is there to account for the fact that your shoulder acts as a pivot point whilst using the saw, thereby keeping more teeth engaged more of the time. It is very difficult to achieve with a machine and so we all ended up with flat edged saws as production was mechanised.

A concave toothed edge is the almost invariably the result of wear and should be removed.

Having said all that, if you are just starting out and are using this as a practice piece for cutting new teeth from scratch or you want to change the pitch, you may want to file out the breasting anyway just to make things easier. If not, I'd just file the old teeth down to an even height and follow the existing gullets.

One top tip I picked up somewhere is to find a bit of old bandsaw blade with the same number of tpi that you want to file into the saw (only when recutting from scratch). Tape it to the side and use it as a template for positioning the gullets, the file will prefer a single thickness of saw blade to a double thickness and therefore tend to drift back into line.

Cheers,


Matthew

 

[mickthetree]

Looking at the picture of breasting the Disston website, the saw I have actually has the opposite. What with this and the bend in the blade, I think this is really a practise piece. Better than practising on a nice new shiny one. ;-)

Actually, looking through the Disston website, I'm sure one of the old rust buckets I have in this box is a Disston. Got a lovely carved handle.

I've already spoken to Matthew about the restore rust remover product he does and I'll pick some up when I get some cash. I'm sure it will prove useful in the future, even if these ones are too far gone.

Interesting how cheap you can pick old saws up for on teh internets, but I think I would want to see one in hand (ie car boot etc) to make sure its straight and see what the teeth are like.

Having said all of this, I intend to get a descent saw from Matthew when I get some funds together. (along with all of the other bits I keep drooling over) ;-)

 

[Harbo]

Could not post photos before but here's some.

The results were much worse in the flesh!!

The Brent Beach type jig was also a disaster:

Or perhaps it was the way I made it - sorry about the big pics!!

Rod

 

[Racers]

Hi, Rod

I've seen worse.

Pete

 

[Mikey R]

Heres a related question - are hardpoint saws made from the same spring steel as classic saws?

So, could a cut a new blade from an old homebase blade and file my own teeth in?