...That keeps me re-visiting them...
I made my first bowsaw sometime in the early 1980s with a 10 inch blade bought from Lee Valley. It was a clunker (no pics, fortunately!), but it did the job well enough for me at the time. About every 5 years or so I've made myself a new one, incorporating minor improvements, and about 6 or 7 years ago, thought I'd pretty well got bowsaws nailed down. I stuck with the 10" blade length because it suits my needs very well, & over time, I've arrived at a style & overall design that works very nicely for me. I use my little bowsaw a lot. End of story.
That is, until Bushmiller caused me to have another look at them (that's my story & I'm sticking to it, Paul! :U), by giving me some blades to see if they would be suitable for a bowsaw. These blades are serious bits of metal! Huge fangs with a positive rake of around 5 degrees - Paul thought they were for an industrial scrollsaw, & I reckon that's what they'd suit, alright. I chose a few with teeth that looked like they might be manageable in a hand-operated saw: Blades.jpg
Paul's are the 3 at the top, a 12mm wide, 5tpi, 5mm wide 6tpi & a 4mm wide 7tpi. The metal is 0.8mm thick (~0.032"). The bottom two are a couple I made up (about which more later).
My own bowsaw takes a 250mm blade, so to accommodate these 12 inch blades I thought I'd just stick a longer beam into one of my 'spare' saws and give one of Paul's blades a run. Well, it just didn't work out. I sharpened up the middle blade, taking the rake back to -5 deg., but it cut like a dog. I decided the short arms & light frame weren't letting me get enough tension on the thick blade.
So I dug out some bits of wattle and started afresh, with some longer & beefier arms: Arms 1.jpg Arms 2.jpg. I couldn't wait to finish the thing before trying it, so I assembled it in the (very) rough state: first assembly.jpg
& took it for a test drive. There was a definite improvement in performance, and the new saw cut tolerably well in soft-ish wood, but was pretty harsh in harder wood. So I made up the couple of blades (at the bottom of the pic above). The wider one is 19mm wide by 0.025" thick, and the narrow one 7mm and 0.020" thick. Both are approximately 10tpi. The wider blade was a meat-saw blade that I had been using as a toothing template, and the narrower blade is cut from an old bandsaw blade. Incidentally, the best way I've found to make small holes in spring steel is to use a glass point drill. I centre-punch the hole position, then very carefully drill from both sides to get the required ~2mm hole: Blade holes.jpg
Here are some cuts made with the two blades I made up: Cuts cf.jpg
The woods are Jacaranda (~45mm thick) and Jarrah (~25mm thick). Reading from the left on each piece, cut 1 is a straight cut to a line, with the 189mm blade (cut pretty clean, & easy to follow the line. Cut 2 is the 7mm wide blade (freer cutting, and reasonably easy to keep on the line). The next two cuts are attempts at cutting the tightest circles possible - the 7mm manages about a 25mm radius, the 19mm managed something like 150mm radius. (Both could do better with more set, of course, but I wasn't aiming for tight circles with this saw, anyway). Just for interest, I tried the narrowest of Paul's blades (4mm) and it easily cut a tight circle of 10-12mm due to lots of set as well as the narrow width.
So I was encouraged enough to go on & finish my saw: Done.jpg
It's noticeably heftier than the 10" size as you can see in this pic: Size cf.jpg
and although not all that much heavier (506g vs 330g) it certainly feels much more solid. I plan to use this one for heavier jobs involving straight cutting & minor curves, but it will take a bit of use before I know if I've got things 'right'. And Paul, the blades you have got your hands on are sort of ok, but I think I'll be mostly using the ones I made, in this saw.... :U
Cheers,
I made my first bowsaw sometime in the early 1980s with a 10 inch blade bought from Lee Valley. It was a clunker (no pics, fortunately!), but it did the job well enough for me at the time. About every 5 years or so I've made myself a new one, incorporating minor improvements, and about 6 or 7 years ago, thought I'd pretty well got bowsaws nailed down. I stuck with the 10" blade length because it suits my needs very well, & over time, I've arrived at a style & overall design that works very nicely for me. I use my little bowsaw a lot. End of story.
That is, until Bushmiller caused me to have another look at them (that's my story & I'm sticking to it, Paul! :U), by giving me some blades to see if they would be suitable for a bowsaw. These blades are serious bits of metal! Huge fangs with a positive rake of around 5 degrees - Paul thought they were for an industrial scrollsaw, & I reckon that's what they'd suit, alright. I chose a few with teeth that looked like they might be manageable in a hand-operated saw: Blades.jpg
Paul's are the 3 at the top, a 12mm wide, 5tpi, 5mm wide 6tpi & a 4mm wide 7tpi. The metal is 0.8mm thick (~0.032"). The bottom two are a couple I made up (about which more later).
My own bowsaw takes a 250mm blade, so to accommodate these 12 inch blades I thought I'd just stick a longer beam into one of my 'spare' saws and give one of Paul's blades a run. Well, it just didn't work out. I sharpened up the middle blade, taking the rake back to -5 deg., but it cut like a dog. I decided the short arms & light frame weren't letting me get enough tension on the thick blade.
So I dug out some bits of wattle and started afresh, with some longer & beefier arms: Arms 1.jpg Arms 2.jpg. I couldn't wait to finish the thing before trying it, so I assembled it in the (very) rough state: first assembly.jpg
& took it for a test drive. There was a definite improvement in performance, and the new saw cut tolerably well in soft-ish wood, but was pretty harsh in harder wood. So I made up the couple of blades (at the bottom of the pic above). The wider one is 19mm wide by 0.025" thick, and the narrow one 7mm and 0.020" thick. Both are approximately 10tpi. The wider blade was a meat-saw blade that I had been using as a toothing template, and the narrower blade is cut from an old bandsaw blade. Incidentally, the best way I've found to make small holes in spring steel is to use a glass point drill. I centre-punch the hole position, then very carefully drill from both sides to get the required ~2mm hole: Blade holes.jpg
Here are some cuts made with the two blades I made up: Cuts cf.jpg
The woods are Jacaranda (~45mm thick) and Jarrah (~25mm thick). Reading from the left on each piece, cut 1 is a straight cut to a line, with the 189mm blade (cut pretty clean, & easy to follow the line. Cut 2 is the 7mm wide blade (freer cutting, and reasonably easy to keep on the line). The next two cuts are attempts at cutting the tightest circles possible - the 7mm manages about a 25mm radius, the 19mm managed something like 150mm radius. (Both could do better with more set, of course, but I wasn't aiming for tight circles with this saw, anyway). Just for interest, I tried the narrowest of Paul's blades (4mm) and it easily cut a tight circle of 10-12mm due to lots of set as well as the narrow width.
So I was encouraged enough to go on & finish my saw: Done.jpg
It's noticeably heftier than the 10" size as you can see in this pic: Size cf.jpg
and although not all that much heavier (506g vs 330g) it certainly feels much more solid. I plan to use this one for heavier jobs involving straight cutting & minor curves, but it will take a bit of use before I know if I've got things 'right'. And Paul, the blades you have got your hands on are sort of ok, but I think I'll be mostly using the ones I made, in this saw.... :U
Cheers,
There's something about bowsaws
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