Thread: Bow saw blades

Originally Posted by markharrison

I'm wondering if you're overthinking this. I made a Gramercy tools bowsaw from their kit and just use brickie's line because its what I had lying around. I had intentions of using something better and replacing it later but it works so well I've just not bothered.

YMMV

Mark, whatever works for the job, works. I'm not particularly fussy about what cord I use, it's just that most modern cord is some sort of synthetic stuff that's very stretchy, but it's not totally elastic-stretchy, & doesn't. return to original length when released, so you find yourself winding more & more turns on to get it tight & pretty soon, it gets too stretched & breaks. Some cord is worse than others, & the cord I found a few years ago is pretty good, it doesn't stretch so much & after a few tightens remains fairly stable.

WP, funny you should mention shoe-laces. I think it was in a very old FWW, or similar mag that I saw an article on making a bowsaw & the author recommended a particular type of boot lace that was super-strong & non-stretchy. I think you only needed one...

I believe rawhide was also popular in days of yore, but that's not so easy to buy at the local hardware store any more. Bow string (as in archery bows) that someone mentioned, should be ideal.....

Cheers,

Paracord is another option to use for bow saw tensioning.

100m 9 Strand Core 4mm Paracord Parachute Cord Tent Lanyard Rope Camping Hiking | eBay

Ian,

You mention that you use your bow saw mostly for curves, hence the 10tpi+ teeth you use.

Still with these cabriole legs I'm making in mind, what do you use for the long "straight" between the knee and the ankle of the leg, which is curved enough so that a backsaw can't help?

I'm assuming here that you aren't burning electrons and heading off to your bandsaw.

I've a feeling the MIL might be asking for a copy of the table I'm making.

Regards,

Adam

Originally Posted by woodPixel

For the cord, one could buy bow strings?

They come in many lengths, especially for compound bows.

They are pre-stretched and are as ineleastic as one can get.
....

Yacht chandleries also sell braided cord made from exotics such as spectre, vectran and others with virtually zero stretch and by the metre. It is extremely strong and difficult to cut without a "hot knife". Can be as fine as 2mm diameter.

Donaghys Superspeed (Spectraspeed) Rope, $1.65 | Whitworths Marine

Originally Posted by taz01

...... what do you use for the long "straight" between the knee and the ankle of the leg, which is curved enough so that a backsaw can't help?

I'm assuming here that you aren't burning electrons and heading off to your bandsaw. ......

Ummm, should I confess? (I have used the bandsaw for 90% of the several dozen cabriole legs I've made )

I am wracking my brains to remember, but I'm pretty sure I haven't made a single cabriole leg since I retired, so all the ones I did were done under the pressure of limited shed time & I went for speed over 'authenticity'. For anything larger than a coffee table, a 1/2" blade did the job, though it often involves a bit of backing & filling if the ankle curve is tight (or leave it & cut the tight section out with the turning saw). Cabriole leg.jpg

When using the bandsaw, you normally stick the waste from the first side cut back in place (I usually do it with masking tape), so you have your lines to follow for the 2nd cut. When doing it by hand, you can re-draw the line for the second cut (with a bit of care), which reduces the thickness to be sawn. You shouldn't have too much trouble keeping within a mm or two of the straighter lines with your new blades - just do a practice cut or two on a piece of scrap & I'm sure you'll get the feel of it pretty quickly. It is always a lot more awkward on these 'long blows' because you have to twist the blade so the frame can clear the piece, which upsets the balance (a good reason to keep your frame as light as possible), & you have to concentrate hard to maintain a smooth cut.

On my first few legs I used spokeshaves a lot for the smoothing & blending, but then I discovered good rasps and since then I've used spokeshaves very little because the constant grain changes don't sit well with spokeshaves. My Veritas shaves don't tear out anywhere near as much as the old Stanley 150 I started with, thanks to their much finer mouths but nevertheless, they can still make a mess on some woods if your mind isn't entirely focused on the job. Rasps, scrapers (if it's a wood that scrapes well) &/or cloth-backed paper are my friends on this sort of job.....

Cheers,

Hi,

This is an old Bow saw of my Great Grandfathers.
It is 36" long with a blade length of 30". Here are a few pics.

Martin.IMG_20210519_105935.jpgIMG_20210519_105940.jpgIMG_20210519_110004.jpgIMG_20210519_110035.jpg

Now THAT'S a bowsaw Martin! Makes my titchy little saw look like it belongs in a dolls' house..

Thanks for posting that, it's interesting to me to see how the frame is constructed, I think there's some lessons there. I first noticed the beam has bridle joints either end instead of little tenons to locate it in the arms as is typical of small saws, & the beam is proportionately thicker than is usual on smaller saws. After thinking about it a bit, I decided such a long beam probably needs extra width to prevent it from bowing to left or right under the considerable tension that long blade will require. The total weight has been kept within reason by making the arms thin, but deep (good girders!). I've not seen a saw like this before so I'm wondering if it's a traditional design in your neck of the woods, or you had a pretty switched-on grandpa who knew a thing or two about making tools?

And it has a deadly set of fangs! Looks like 2-3tpi - do you know what it was used for? Ripping thick planks for boats, perhaps? The shape of the "handle" implies it was used vertically, with fingers wrapped around the 'hook' & thumb in the hole, but maybe there's a totally different reason for that unusual shape?

Cheers,

Ian

On our Sunday evening prattle the subject of vintage European saws came up and why we do not see many in the same way we see British and American saws (Scandinavian too). I concluded that it was because they used bow and frame saws instead of our more familiar hand saws. I did put up some pix there.

Here are some more from the 1932 Peugeot catalogue (easier to see when enlarged again):

Peugeot 1932.jpg

It seems they offered both the bridle joint style and the tenon. The turning saw had blades from 5mm wide to 15mm wide and blades up to 850mm long. The frame saws with blades to 1.5m long were typically from 40mm wide up to 80mm wide. Interestingly all were tensioned with a cord. It occurred to me that if tensioning was an issue for replicating these saws and achieving sufficient tension a small turnbuckle would work. but that does necessitate a rod either end to resisting turning as the buckle is wound in. You may recall this was used extensively for buck saws and "wood" saws.

The timbers were either "fruit," ash or beech and another timber "Charme", but I have not worked out what that is.

I have quite a few more shots from two catalogues if you wish, but won't burden the thread with too much stuff from this time past.

Regards
Paul

Originally Posted by Bushmiller

Ian

On our Sunday evening prattle the subject of vintage European saws came up and why we do not see many in the same way we see British and American saws (Scandinavian too). I concluded that it was because they used bow and frame saws instead of our more familiar hand saws. I did put up some pix there.

Here are some more from the 1932 Peugeot catalogue (easier to see when enlarged again):

Peugeot 1932.jpg

It seems they offered both the bridle joint style and the tenon. The turning saw had blades from 5mm wide to 15mm wide and blades up to 850mm long. The frame saws with blades to 1.5m long were typically from 40mm wide up to 80mm wide. Interestingly all were tensioned with a cord. It occurred to me that if tensioning was an issue for replicating these saws and achieving sufficient tension a small turnbuckle would work. but that does necessitate a rod either end to resisting turning as the buckle is wound in. You may recall this was used extensively for buck saws and "wood" saws.

The timbers were either "fruit," ash or beech and another timber "Charme", but I have not worked out what that is.

I have quite a few more shots from two catalogues if you wish, but won't burden the thread with too much stuff from this time past.

Regards
Paul

This might be your answer (from the French Wikipedia):

Charme — Wikipedia

The Latin name is carpinus. More goggling gives this to be "hornbeam" which is also known as ironwood.

Regards,

Adam

Thanks Adam

Hornbeam it is. Same price as Beech.

Regards
Paul

Paul, as Adam has already discovered the mystery wood is hornbeam, which was/is a favoured wood for tools on the Continent. German planes are often advertised as having hornbeam soles, because it is both tough & abrasion-resistant. Do they call Carpinus "ironwood" in Europe? In eastern U.S. & southern Canada there is a tree which is in the same family as hornbeam (Carpinus) called "Hop-hornbeam", aka "ironwood", botanical name Ostrya virginiana. The American version of 'true' hornbeam (C. carolineana) grows in much the same area, but where I lived in Canada it didn't form a very big tree, the largest I saw was only about 200mm diameter max. It also has a peculiar, irregularly-fluted trunk (which gives it one of its common names of "musclewood") so the few bits of it I got my hands on didn't yield much useable wood. It turned & threaded beautifully & I made a couple of clamp screws with it. The tree was also commonly known as "Blue-beech" in Southern Ontario where I was living (both species are actually in the same family as beech). Plant common-names do get a little confused & confusing, don't they?!

Something that occurred to me is that connecting the beam to the arms with a bridle joint as in Martin's example & several of those on your catalogue page, could allow you to adjust its position to give more clearance when necessary. No form of locating the beam at any particular point is shown in the catalogue pics, so I'm assuming it is just a firm sliding fit ot there are pins that the artist didn't bother to render.

Cheers,

Originally Posted by IanW

Ummm, should I confess? (I have used the bandsaw for 90% of the several dozen cabriole legs I've made )

I am wracking my brains to remember, but I'm pretty sure I haven't made a single cabriole leg since I retired, so all the ones I did were done under the pressure of limited shed time & I went for speed over 'authenticity'. For anything larger than a coffee table, a 1/2" blade did the job, though it often involves a bit of backing & filling if the ankle curve is tight (or leave it & cut the tight section out with the turning saw). Cabriole leg.jpg

When using the bandsaw, you normally stick the waste from the first side cut back in place (I usually do it with masking tape), so you have your lines to follow for the 2nd cut. When doing it by hand, you can re-draw the line for the second cut (with a bit of care), which reduces the thickness to be sawn. You shouldn't have too much trouble keeping within a mm or two of the straighter lines with your new blades - just do a practice cut or two on a piece of scrap & I'm sure you'll get the feel of it pretty quickly. It is always a lot more awkward on these 'long blows' because you have to twist the blade so the frame can clear the piece, which upsets the balance (a good reason to keep your frame as light as possible), & you have to concentrate hard to maintain a smooth cut.

On my first few legs I used spokeshaves a lot for the smoothing & blending, but then I discovered good rasps and since then I've used spokeshaves very little because the constant grain changes don't sit well with spokeshaves. My Veritas shaves don't tear out anywhere near as much as the old Stanley 150 I started with, thanks to their much finer mouths but nevertheless, they can still make a mess on some woods if your mind isn't entirely focused on the job. Rasps, scrapers (if it's a wood that scrapes well) &/or cloth-backed paper are my friends on this sort of job.....

Cheers,

I'm on leg 3 of 4 and making slow but steady progress. This isn't anything to do with the blade but lack of shed time after starting a new job.

I'm taking a slightly different approach with cutting out the leg, doing a quarter at a time but not sawing to the point the waste wood come off. Leaving it still attached i then have my guide for the cut on the other face.

I'm still getting used to the bow saw, but starting to be able to follow the line a little easier. I traced the pattern onto the black with a sharpie so it's much easier to see when I'm getting too close.

Rasps are doing the tidying up but I'm mostly using my shinto ones. They cut very quickly on the course side. Once i have the roughed out shape then i can start rounding over.

Slow progress is still progress!

A useful tip I got from an old FWW was to use a bar clamp to hold the leg when fairing the curves. You can hold the clamp in the front vice or between the bench dogs, & this arrangement gives you better access to more leg at any one time.

I use one of my wooden bar clamps: 3 1M bar clamps.jpg

This gives me better access & is easier to hold than a pipe clamp, which the bloke in the original article was using, but a pipe clamp will do the job. Sorry I don't have a pic of a leg being worked on, but I think you'll get the idea....

Cheers,

Earlier on in the thread, there was a brief discussion of what cord to use for your bowsaw. Adam (Taz01) said he was using kite string & offered to send me some to try. The string duly arrived a couple of weeks ago but I've been a bit busy with non-shed matters & hadn't got around to doing much about it 'til he jogged my memory, so apologies for my tardiness...

OK, so I've now done a little comparison. The kite string is about 0.5mm diameter as close as I can measure it, but that may be way off 'cos it's rather difficult to get an accurate measurement of such compressible material. It looks a bit thicker than half a mm lying loose on the bench beside the 3mm venetian blind cord that I've been using, but not that much: Kite & ven cords.jpg

But taking the 0.5mm diameter as a ballpark figure, I calculated the cross-sectional area of each, & the kite string comes out at ~1/37th the cross-section of the venetian cord. I use a single turn of cord on my two smaller saws, which means I should have had about 37 rounds of string to equal one round of cord. I didn't have enough string for that, I only achieved 12 rounds on my smallest bowsaw (the one that takes coping saw blades). When tensioned up, it's pretty clear that I'd need at least another dozen rounds of string to get a similar cross-section under tension. Here it is tightened up, compared with the cord on my 12 inch saw (on which I've used two rounds, as you can see) but I think you can see that the bundles of kite string have reduced to something less than the diameter of a single venetian cord: Kite & ven cords2.jpg

I've tensioned the string as much as I could, but it got to the stage where it felt like it was stretching more than adding tension. I tried cutting with the saw & it was ok, but I felt the blade could have done with more tension than I was able to apply with this many rounds of string.

So, based on this brief & not terribly scientific test, the kite string could probably do the job, but I use two rounds of venetian cord on my 12 inch saw to get good tension, so by my reckoning you'd be looking at 60-70 rounds of kite string to get the same effect. It also felt a bit more stretchy than the vc, but that was probably due to not having enough rounds, my guess is that they are made of similar material.

So, Adam, it's possible that part of your woes is that you are not getting sufficient tension on your blade. An under-tensioned blade doesn't track as well as one under sufficient tension. It might be worth your while investigating this aspect a bit more. I've got a whole reel of 3mm cord so maybe I should return the favour & send you a bit to try on your saw...

Cheers,