Thread: Bow saw

IanW

Hope you had a good time with the grandchildren

Always appreciate your informative and comprehensive answers.

I have never toothed my own blade and while it is unliky to happen before Christmas it is something I want to try.

Maybe at my next get together it will happen with a little help from someone who has the experience if such a lersin is present



Dave TTC
Turning Wood Into Art

Originally Posted by IanW

. . . . . I certainly wouldn't try to use the existing teeth, they are usually far too coarse & far too aggressive for a small bowsaw. Most blades these days are impulse-hardened and the teeth can't be filed, as BobL has pointed out, so it's no use trying to alter the existing tooth profile with a file. Instead, I'd cut off a strip & re-tooth it - the hardening only extends to half a mm or so beyond the bottom of the gullets. For small saws (up to 12 inch blades), I've found somewhere between 12 & 15 tpi works well, depending on the average thickness of what you want to cut with them. (In fact, I just cut out a plane tote from 24mm thick Wattle this afternoon with a 15tpi, 10 inch saw this afternoon & it was just right for the job! ) There are plenty of ideas for ways of extracting dust from above the saw table.

I've currently got a piece of 14TPI metal cutting bandsaw blade from my metal cutting bandsaw on my small bowsaw
These are a relatively common blade and as they can cut mild steel they are tough as.
I have a heap of broken blades - if anyone want a piece or two of these they are welcome.

When I was making turning saws, I purchasing approx. 100 blades. Traditional NOS from the U.K. Length around 12 inch, depth less than 1/4 inch . Forget what the tpi's are. The blades were not pre pinned like the modern blades are, but they had a pre bored hole each end to accept a very fine pin. I ended up drilling the holes out to larger bore on the blades I used because I couldn't track down pin stock with a matching dia.

Stewie;

That twisted blade may not be 'damaged junk', it may have been deliberately done to make it easier to cut waste from dovetails - something made popular in the US by Frank Klaus, but no longer offered by any of the Internet retailers. Roy Underhill makes his own in one of his shows.

You start with the vertical piece of the blade in the slot then when it gets down near where you want to cut horizontally you just change your stroke until the twisted part enlarges the slot and then finish with the bit that is horizontal, no stuffing around twisting handles and adjusting tension.

Originally Posted by planemaker

... but they had a pre bored hole each end to accept a very fine pin. I ended up drilling the holes out to larger bore on the blades I used because I couldn't track down pin stock with a matching dia. .....

How small were the holes, Stewie? I bought my first blades from LV (a very long time ago!), & the pin holes were about 1mm diameter on those. I use small brads for pins, which work just fine. I bend the ends a little to stop them falling out when the cord is loosened. It's a slight pest having to reach for a pair of pliers whenever I need to insert the blade for an inside cut, and the nail breaks after being un-bent a couple of times, but I have plenty of brads.....

Cheers,

Originally Posted by bsrlee

That twisted blade may not be 'damaged junk', it may have been deliberately done to make it easier to cut waste from dovetails - something made popular in the US by Frank Klaus, .....

I was thinking the exact same thing, bsr - I remember an article in FWW, a half a lifetime back, where he showed how to modify a blade. As I recall, he only used these blades for cutting what he called "utility" dovetails, for packing crates, etc, not for fine furniture. I modified a blade and had a go at it, at the time, but the results I got couldn't be described as "utility"; "hideous" would be a better description! Obviously takes a bit of practice to have 'em look as convincing as Klausz's were.

So I saw the straight cuts with a backsaw, then remove the bulk of the waste with a bowsaw. With a 5mm wide blade, I can saw out all but about 0.5-1mm of the waste in two quick cuts, even in small dovetails, then finish with a chisel.

Just a side note: There are some, like my old cabinetmaker mentor of many years ago, who claim this is not the 'proper' way to do dovetails. He insisted on using a chisel only to remove the waste, for reasons he never fully explained to me, but I suspect had more to do with the way he was trained and the perception that it is quicker than anything else. However, I'd be quite happy to recant if anyone can give me a good reason why that is a better method. I can give you two reasons why I do remove the bulk of the waste: 1. With only a mm or less of waste to remove, it is much easier to keep the chisel cut dead on the scribe line, there is less resistance on the bevel side forcing it back into the 'good' wood & causing 'overcutting'. 2. Because I use one of these silly ultrathin dovetail saws (), the saw cuts are very fine, & there is no 'wriggle room'. If I try to chisel the waste directly, the wedge of waste tends to jamb in the slot. This is a minor irritation, but it is additive & when you have a whole lot of tails to make, gets downright annoying! In softer woods like Aust. cedar, the jammed wedge can also sometimes cause a bit of breakout or bruising, which Murphy ensures is always on the show side. Sawing out the bulk of the waste with a good bowsaw is quick and makes the process far more efficient overall, in my hands...

Cheers,

Hi Ian. Its been a long while since I had a close look at these blades. The distance between the pin holes is 12 inch; @10 tpi; pin hole dia. is 1.6mm.

Stewie;

So if i got this right my blade may be fine as is, just needs a sharpen?

Dave TTC
Turning Wood Into Art

Originally Posted by DaveTTC

So if i got this right my blade may be fine as is, just needs a sharpen?

Dave TTC
Turning Wood Into Art

Could be, Dave, if you want to try your hand at cutting dovetails the Klausz way. But you would probably find more general use in a simple straight blade like the ones Stewie shows.

Stewie, 1.6mm (1/16") is a very common small nail size, so next time you need pins, just jog on down to the nearest hardware store....

Cheers,

If all bow saws were constructed like this one, you wouldn't have to worry about finding a new blade!
http://www.wkfinetools.com/hUS-saws/...-jClark-01.asp

Wow!!! That is impressive

Dave TTC
Turning Wood Into Art

NOW you've thrown me a challenge, HR!

My saw's beam is 15mm thick and less than 20mm wide, so drilling a hole big enough to hold a coupe of spare blades through it is going to require some heavy concentration (& a few expletives, no doubt!). But it's such a good idea, I simply have to have a bash at it. I gues I have plenty of spare wood to make several more beams if necessary....

Cheers,

It's a great idea. Making the stretcher in two parts and gluing up will be easier.
Might have to have a go myself.

Originally Posted by hiroller

It's a great idea. Making the stretcher in two parts and gluing up will be easier.
Might have to have a go myself.

Nah - that's too easy - I'm up for a challenge! (But you won't hear about it unless I'm successful! )