Cutting Saw Teeth

[Jelly]

I've just been offered a small fly press, which I recall are the tool of choice for hobbyist/low volume production cutting of large saw teeth from spring steel stock, I have a few questions on this:

• Would a fly-press be able to cope with spring steel which has been hardened and tempered, by the manufacturer/stockholder.
• Where would I get tooling for cutting saw teeth, is there likely to be anyone holding stock punches & dies for cutting a three square triangle, or would I just have to create drawings and take them to a tool & die maker?
• How easy is it to build jigs which align, support and reproducibly move the workpiece across the face of the die?

 

[blackrodd]

Found this on u tube, I only had a quick look but it seems to be how I remember it being done!
Steel was supplied to us in sheets or rolls.
Pick the steel carefully, we had one lot and the teeth just snapped off when using the saw set :shock:
Google have some on the subject.
Regards Rodders

https://www.youtube.com/watch?v=LQPb3-no7b4

 

[Mike.S]

Interesting video Rodders posted. Here's another one, showing Thomas Flinn's operation. It's about large X-Cut saws but shows the teeth cutting press set-up clearly.

Please do post updates if you decide to progress this project.

 

[Jelly]

I've accepted it, so just need to sort tooling, I think I's a level of precision I'm unlikely to achieve myself... But the tool and die maker across the road from our lass's flat ought to be able to sort it out fairly easily... But maybe not cheaply.

 

[woodpig]

Old saws used to be sharpened easily enough with a three square file so the steel could not have been that hard. There was a guy on one of the forums that used to even re cut completely new teeth on old saws using just a file.

 

[RogerP]

Old saws used to be sharpened easily enough with a three square file so the steel could not have been that hard. There was a guy on one of the forums that used to even re cut completely new teeth on old saws using just a file.

I've done that myself just the once. It was a very old tenon saw in fair condition with a lovely handle but some teeth were broken and it had been poorly sharpened in the past and was very uneven. So I grasped the nettle and ground all the teeth off and recut them using three-square files. Took a while but the end result was good.

 

[woodpig]

I understand the important part is marking out and clamping the blade properly, the actual cutting with a file part not taking that long. Easy to say as I've not done it but that was the impression I was given! :lol:

 

[Jelly]

Old saws used to be sharpened easily enough with a three square file so the steel could not have been that hard. There was a guy on one of the forums that used to even re cut completely new teeth on old saws using just a file.

I've done that myself just the once. It was a very old tenon saw in fair condition with a lovely handle but some teeth were broken and it had been poorly sharpened in the past and was very uneven. So I grasped the nettle and ground all the teeth off and recut them using three-square files. Took a while but the end result was good.

I have done just that myself, re-cutting a 24" Tyzack panel saw with battered old Fleam-Cut teeth into a 2.75tpi Rip Cut with a uniquely aggressive progressive rake*, I must have used 4 files up doing that... Never Again (hopefully if i sort out this fly-press).

It was that which started me on this idea, as I'd like to experiment more with saw geometry and design, and have at least two saw-plates sitting around which could take new teeth.


*The rake begins 10 degrees from vertical at the start, quickly to vertical and finally to 7 degrees over vertical (ie the gullet underneath and behind the cutting edge, much like a bandsaw blade) in the final 10" to the handle; sounds weird, is weird, cuts very well, just requires a slightly lighter touch.

 

[Jelly]

I've secured access to a milling machine and prepared all my drawings so hopefully I can get the tooling machined to approximate size next weekend (If i can source a small order of D6 bar and rod by then).

Still working out where to get the heat treatment done, but i'll have time to work on that whilst I'm scraping it all down to the desired tolerances (in hindsight, I did not realise how fine a clearance I'd need for punching sawplates at 35 thou, I'm not sure I even want to try for the tolerances reqired to get down to 15 thou superfine backsaw plate standards.)

I can't find a punch holder anywhere to fit my press, so I'm going to have to turn one of those too, TBH I'm struggling to even find out what one should look like, so I've just designed one that makes sense from first principles.

 

[Cheshirechappie]

Whilst I very much admire your gung-ho determination to get stuck into the project, I wonder whether the time and effort might be better spent in refiling a few secondhand saws if experiments with tooth geometry is the aim. There's quite a cost involved in the materials and manufacturing processes for even quite simple special press tooling, and the time involved in getting it set up and tuned might be significant as well. There is also the factor that punchwork to thin material can cause distortion, and either dressing that out or finding a way to avoid it would take more time; then there's the cost of obtaining small quantities of spring steel stock to experiment on, and then you still have to put handles on the resulting punched blades.

For the cost of a box or two of files, some Ebay saws (which can be picked up for nearly pennies these days) and some time, quite a few modified geometry saws could be turned out. I've no idea where the 'break-even' point of specialist press tooling would be, but I suspect you'd have to be thinking about medium-scale saw production to make it worthwhile.

 

[Jelly]

Whilst I very much admire your gung-ho determination to get stuck into the project...

I've been filing my own saws, and those of friends, for a couple of years now and have experimented with cutting some unconventional geometries by file, I've also more recently learned about flattening bent saws with a hammer and anvil, which leads on to "tensioning" saws, which is a convoluted way of saying you've peened it into a curve on one side, then back to flat by peening on the other, so the work hardening will add rigidity; this same process also allows you to counteract the deformation of the plate from the punching stresses (which itself can be nearly minimised by using a sufficiently fine clearance twixt punch and die).

I'm totally aware that this is a wholly uneconomic way of learning further about making saws...

Buuuuut, I enjoy the challenge, and if I get good enough to justify it, I might have a crack at selling a few saws... However if I don't I will still have taught myself a lot more about machining, toolmaking, punch and die setup, saw tensioning, saw geometry, heat treatment and handle ergonomics by the time I'm done; Given how little satisfaction i get from my day job of late, I'm happy to spend money to do something I'll enjoy and grow through doing...

 

[Droogs]

Well said Jelly, sometimes the journey itself is the destination. I wish youthe best in your endevour and hope it will be both an informative and pleasurable experience.

 

[Cheshirechappie]

I enjoy the challenge, and if I get good enough to justify it, I might have a crack at selling a few saws... However if I don't I will still have taught myself a lot more about machining, toolmaking, punch and die setup, saw tensioning, saw geometry, heat treatment and handle ergonomics by the time I'm done; Given how little satisfaction i get from my day job of late, I'm happy to spend money to do something I'll enjoy and grow through doing...

Fair enough! As long as you're going into it with your eyes open. Good luck, and have fun.

 

[woodpig]

It sounds like a fair bit of work but you seem to know what you're doing so I expect you'll have fun on the way. You never know, you could end up making custom saws with a good mark up, fingers crossed!

 

[Jelly]

It sounds like a fair bit of work but you seem to know what you're doing so I expect you'll have fun on the way. You never know, you could end up making custom saws with a good mark up, fingers crossed!

Know what I'm doing might be an overstatement!

I have rapidly aquired a lot of knowledge, and a used that to form a plan; experience teaches me that following the plan through will be hard and time consuming, but entirely achievable.

The ability to take on this type of project with my eyes open is probably the number one benefit of studying a STEM subject at Uni (far more than any percieved employment opportunities), once you've been forced to take on practical projects with limited support and limited prior knowledge, it opens your eyes to what you can accomplish if you do your research and make a plan.

 

[AndyT]

It sounds like a fascinating plan to me!

Noting your location, and picking up on Mike S's response, have you tried talking to the people at Thomas Flinn in Sheffield, our last commercial maker of handsaws? Their MD posts on here occasionally so is presumably an approachable sort of person, and her family and staff must have a lot of this detail in their experienced heads.

 

[Jelly]

It sounds like a fascinating plan to me!

Noting your location, and picking up on Mike S's response, have you tried talking to the people at Thomas Flinn in Sheffield, our last commercial maker of handsaws? Their MD posts on here occasionally so is presumably an approachable sort of person, and her family and staff must have a lot of this detail in their experienced heads.

I live just round the corner from both them and Atkinson Walker, but I'm yet to get an opportunity to go in due to my working hours...

I dunno though, it kinda feels cheeky to go asking their advice when I'm not a customer (though they do sell froes, which I could probably do with at some point before I go splitting more of my logs).

In getting access to the milling machine needed to make my punches, I've ended up volunteering to help rennovate a wadkin-bursgreen planer-thicknesser... So I now have projects coming out of my eyeballs!