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Thread: Coping/Turning/Bowsaw design

  1. #1
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    Coping/Turning/Bowsaw design

    Howdy friends

    In the last few days I've have become bowsaw curious. I was making a new shelf for my wife that had some scroll work to be done for the sides (with sliding dovetail shelves if you must know). Kinda shaker-esque.

    I really do not enjoy using my Olsen coping saw and sometimes I just don't wanna use the bandsaw.

    This got me thinking about bowsaws. I know they tension much better than a metal frame coping saw and seem to be capable of the same cuts.

    I work really close to Tools for Working Wood and plan on swinging by tomorrow to pick up some pins and string to make one.

    Here is where I'm looking for advice. I'm not one for embellishment when it comes to tools. I will probably just make the arms straight and simply turn the winding pin and knobs. Is there any advantage to the curved arms? I'll attach a pic of what the Gramercy kit TFWW produces specs.

    I'm considering a stretcher with through mortises with the arms loosely fitting through them and the string and pins attached as normal. I'll attach a photo of that as well. I think I read Bob Smalser recommended 5/4 material, seems bulky. I'm trying to figure out a good balance for the through mortise style. 5/4 stretcher and 3/4 arms? The Gramercy saw is 11/16th.

    Would you recommend buying the Gramercy hardware? Buying the whole saw? Or make the hardware as well?

    Also, I know there is a current bow saw thread going, but I believe that was of the more robust variety. I'm looking to make a turning saw using the 10 1/2" 10tpi Gramercy blade. So I hope this isn't redundant. I may have been inspired by that thread

    All thoughts appreciated.

    Last edited by chuck van dyck; 01-30-2022 at 11:16 PM.

  2. #2
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    I forgot to mention material. I have a lot of ash around I would like to use. I know hickory or beech is thought to be best, but I don't have any on hand. I have lots of white oak, ash, sapele, and cherry.

  3. #3
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    IMG_20220123_112230461.jpg

    I've been building one from m the Gramercy plans. I recommend buying the hardware, even though I am making my one from scratch.

    I don't know if the curves serves a functional purpose, but I do know you don't want something heavy and unwieldy. The curves may help cut weight

    Or if you are in a rush, buying one is the easiest option.
    Last edited by Jason Buresh; 01-30-2022 at 10:30 PM.

  4. #4
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    Quote Originally Posted by chuck van dyck View Post
    Howdy friends

    In the last few days I've have become bowsaw curious. I was making a new shelf for my wife that had some scroll work to be done for the sides (with sliding dovetail shelves if you must know). Kinda shaker-esque.

    I really do not enjoy using my Olsen coping saw and sometimes I just don't wanna use the bandsaw.

    This got me thinking about bowsaws. I know they tension much better than a metal frame coping saw and seem to be capable of the same cuts.

    I work really close to Tools for Working Wood and plan on swinging by tomorrow to pick up some pins and string to make one.

    Here is where I'm looking for advice. I'm not one for embellishment when it comes to tools. I will probably just make the arms straight and simply turn the winding pin and knobs. Is there any advantage to the curved arms? I'll attach a pic of what the Gramercy kit TFWW produces specs.

    I'm considering a stretcher with through mortises with the arms loosely fitting through them and the string and pins attached as normal. I'll attach a photo of that as well. I think I read Bob Smalser recommended 5/4 material, seems bulky. I'm trying to figure out a good balance for the through mortise style. 5/4 stretcher and 3/4 arms? The Gramercy saw is 11/16th.

    Would you recommend buying the Gramercy hardware? Buying the whole saw? Or make the hardware as well?

    Also, I know there is a current bow saw thread going, but I believe that was of the more robust variety. I'm looking to make a turning saw using the 10 1/2" 10tpi Gramercy blade. So I hope this isn't redundant. I may have been inspired by that thread

    All thoughts appreciated.

    It's important to distinguish between the different types of bowsaw.

    The first picture you posted is of the small turning saw, which is used to cut out curves in lieu of a coping saw. These usually have wooden handles with metal rods for the blade mounting system.

    The second picture you posted is of an entirely different style of bow-saw; a large, usually 600cm to 700cm general purpose saw, usually fitted with a wider blade for straight cuts. These are large saws akin to western panel saws, but are more general purpose and can be used for crosscutting, ripping, joinery, and even for cutting curves, depending on which blade you use. For general work, wider blades of about 3/4" to 1.5" are common. For curved cuts, 1/4" to 3/8" is common (you can use bandsaw blades for this. Just cut them down and drill two holes).
    These saws usually have the blade mounted in one of five ways:
    1. The oldest and most primitive, not in common use, is to just have a wooden handle which terminates in a wooden peg with a slot and hole for a crosspin to hold the blade. This can split, as you would imagine, and so isn't in common use these days, but in my experience, it's worked just fine and I haven't had any handles split on me yet.
    2. The second oldest is to have all wooden handles, but have the blade become narrower and go through the handle, and pin it on the other side (ie, you cut a really deep slot in the handle all the way down the tenon and past the shoulder, and pin it on the other side of the upright beam into which the handle fits. This prevents splitting, but requires that blades be shaped in a particular way, and longer than usual.
    3. The modern way, which is to do something akin to #2, but with separate metal parts for the bit that goes through the handle and the blade itself. This is the type depicted in your second photo.
    4. The "hardware" method. This is quite common in Chinese bowsaws and there are many historical examples of European saws built this way too: just take bolt, and use a hacksaw to cut a groove into it lengthwise and drill a hole for the pin. Be sure to roughen up the bolt with scratches and drill a very tight fitting hole for it if you use this method, because you don't want it too loose or the blade will turn of it's own free will and you won't be able to guide the saw.
    5. The turning saw method. This is like the Gramercy bowsaw kit and the first picture you linked to: a wood handle into which is fitted a brass pin that holds a small, narrow turning blade. To my knowledge this method is only used on small turning saws and not larger bowsaws.

    Lastly, there's the dedicated joinery saw, and the crosscut saw, which use the same construction: a fixed blade mounted in a slot. These are popular with bushcrafters, but haven't seemed to catch on with the woodworking community, and even those who regularly use bow-saws seem to prefer the general purpose bow-saw with turning handles even for cutting joinery. Nonetheless, this style of saw was very common and is depicted in many Historical manuscripts, such as Roubo and Moxon.

    I prefer to use the larger, general purpose saws with turning handles or bolts, as you can use it for everything and just change out the blades. Bandsaw blades can be great for cutting out curves or cutting metal, and the wider ones can even work okay for general rough cuts and ripping, but aren't the most ideal. Try to find bandsaw blades without the stupid wavy set, and without an aggressive, hooked-tooth rake on them -- just a 90 degree rake is better. You can purchase or make your own blades from 0.5mm sheet steel strips / clock springs, etc. Mostly, I've used the "hardware" method of just taking a bolt and cutting a slot and drilling a hole, but as I said, you need to get the fit tight and scratch up the bolt so that it doesn't rotate freely on you. Tensioning the saw alone is not sufficient to keep wider blades from turning if the bolts are loosely fitted.

    Nicer handles made of wood should be tapered slightly so that as they wear, they remain tight fitting and lock the blade under tension.
    Last edited by Luke Dupont; 01-31-2022 at 4:10 AM.

  5. #5
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    Hey Luke

    Thanks for the thoughtful writeup.

    I made a lazy choice for my second reference photo. What I was trying to show was a particular design element less than the overall saw design. It has a through mortise in the stretcher vs mortises in the arms. I believe this would scale down to turning saw size, but would obviously have some bulk in the stretcher. I’ve also seen examples utilizing a bridle joint.

    The through mortise just makes most sense to me at the moment. As I write this I’m starting to question the thickness that it would require though. I’m hoping Joel will be at Tools for Working Wood later and I can pick his brain.

    As stated before, I’m lucky and my shop is a 5 minute drive from Tools for Working Wood which is where the Gramercy saws are made. Joel put some though into fabrication of pins and a blade specifically to solve some problems of old with turning saws.

    I did find another kit on taylor tools that utilizes standard coping saw blades.

    I’m pretty jazzed to get started on one of these.

    Jason, your saw is looking great!

  6. #6
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    Quote Originally Posted by chuck van dyck View Post
    Hey Luke

    Thanks for the thoughtful writeup.

    I made a lazy choice for my second reference photo. What I was trying to show was a particular design element less than the overall saw design. It has a through mortise in the stretcher vs mortises in the arms. I believe this would scale down to turning saw size, but would obviously have some bulk in the stretcher. I’ve also seen examples utilizing a bridle joint.

    The through mortise just makes most sense to me at the moment. As I write this I’m starting to question the thickness that it would require though. I’m hoping Joel will be at Tools for Working Wood later and I can pick his brain.

    As stated before, I’m lucky and my shop is a 5 minute drive from Tools for Working Wood which is where the Gramercy saws are made. Joel put some though into fabrication of pins and a blade specifically to solve some problems of old with turning saws.

    I did find another kit on taylor tools that utilizes standard coping saw blades.

    I’m pretty jazzed to get started on one of these.

    Jason, your saw is looking great!
    When you say through mortise, you mean a mortise in the stretcher as depicted in the photo right?
    Small turning saws almost always just use a shallow mortise into either arm (1/4" or so) and tenons cut into the stretcher. This allows the stretcher to be thinner and lighter and is better suited for a small turning saw.
    Only larger saws generally use through mortises or bridle joints in the stretcher. Large saws do occasionally use shallow mortises cut into the vertical pieces and tenons cut into the stretcher, like small turning saws do, however.

    I prefer the mortise and tenon joint, as it's easy and not so bulky. I've also never seen a small turning saw using a bridle joint or through mortises, so I'd recommend it for your application.

    Edit: One last point -- I'd go with traditional slit / pin mounts on the handles rather than coping saw style mounts... because coping saw blades are quite short, and you lose the advantage of having a bow saw which can take a longer blade. Of course, you could always have multiple handles and stretchers to accommodate all kinds of blades, if you like.
    Last edited by Luke Dupont; 01-31-2022 at 8:36 AM.

  7. #7
    I made a turning saw based off of the design TFWW has online. It gets an awful lot of use. Here’s some of my observations:

    1) Ash should be fine. Mine is made from red oak – very similar. I think straight grain is more important than wood choice because of the forces involved.

    2) The tapering of the arms helps reduce weight. On a non-turning saw weight might be helpful. On a turning saw weight is your mortal enemy. Aside from making you work harder for the cuts, most of which aren’t going straight down, it will cause the whole frame to succumb to gravity and rotate on you. The grip I use is to hold the stubby handle and pinch the frame at the same time to help prevent this (can’t remember where I learned this, Frank Klaus video I think). But the more weight on the frame you have, the more effort to pinch and keep it from flopping. This is especially the case when you need to hold the saw horizontal to earth to make the cut.

    3) The reason to put the mortise on the arms is the same as above. If you put through mortises on the stretcher it will have to be a lot thicker and that’s more weight. And again, weight is your mortal enemy.

    4) Most of the internet will tell you that you need the strongest string on the planet. 8000lb Kevlar quadruple braided deep sea finish line! And double it up 18 times!!! No. Just no. The string should be WEAKER than the arms of the saw. If you have a failure, you want the string to break; not the arms. An arm breaking will bring everything to a grinding halt and now you have a new project (making a new arm) instead of the current project you are working on. I use regular jute twine, which is 7lb line I believe, and I double it up once which can give plenty of tension on the blade. It’s not just a matter of tension on the blade though. It’s also that when you are pushing through insanely thick stock you are putting compression forces on the bottom of the arms (below the stretcher) and if there’s enough force, something will have to give. I have done this once going too aggressively (who has patience?) on 3” stock and it was a crazy loud CRACK! And things exploded. My initial thought was “no not an arm!!!!” But all the parts were fine. It was the string. It did what it was supposed to do and all I had to do was cut a new length of string and tie a not – I spent most of the couple minutes finding the bundle of twine.

    5) I did not use the Gramarcy hardware. I cut the heads off bolts, cut a slot, cut a groove (to keep it from twisting in the handle), drilled a hole, and epoxied them in. I use a bandsaw blade (a lifetime supply of blade material for $10) and drilled a corresponding hole at each end of the length I used. I cut a finish nail to hold it all together. If you look carefully I put a kink in the nails so they don’t fall out when the tension is removed, but I can still put them out if needed. One advantage of the Gramarcy pins is that they can accept blades that are 1/8” I think, whereas if you have to drill a hole 3/16” is about as small as you can go. They also look prettier, although I think you have less options for blades which might not really matter at all.

    6) I went through a couple blades trying to figure out what worked best. I settled on this one https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 which is 3/16, 10tpi, 0.25 thick. I learned the hard way not to go thinner than 0.25 because the blade will twist too much when you make a tight turn. I also learned that there’s no reason to go below 10tpi because I’m basically never ever making a finish cut with this thing. Anything visible will ultimate be hit with a file, or spokeshave, or sandpaper. Aggressive tpi and set both make it easier to cut faster and also make tighter turns. The only reason I see to go smaller than 10tpi is if cutting really thin stock, like 1/8”, or in some other very fragile situation. I’ve cut plenty of ¼” with no problems at 10tpi.

    turn1.jpgturn2.jpgturn3.jpg

  8. #8
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    Quote Originally Posted by chris carter View Post
    I made a turning saw based off of the design TFWW has online. It gets an awful lot of use. Here’s some of my observations:

    1) Ash should be fine. Mine is made from red oak – very similar. I think straight grain is more important than wood choice because of the forces involved.

    2) The tapering of the arms helps reduce weight. On a non-turning saw weight might be helpful. On a turning saw weight is your mortal enemy. Aside from making you work harder for the cuts, most of which aren’t going straight down, it will cause the whole frame to succumb to gravity and rotate on you. The grip I use is to hold the stubby handle and pinch the frame at the same time to help prevent this (can’t remember where I learned this, Frank Klaus video I think). But the more weight on the frame you have, the more effort to pinch and keep it from flopping. This is especially the case when you need to hold the saw horizontal to earth to make the cut.

    3) The reason to put the mortise on the arms is the same as above. If you put through mortises on the stretcher it will have to be a lot thicker and that’s more weight. And again, weight is your mortal enemy.

    4) Most of the internet will tell you that you need the strongest string on the planet. 8000lb Kevlar quadruple braided deep sea finish line! And double it up 18 times!!! No. Just no. The string should be WEAKER than the arms of the saw. If you have a failure, you want the string to break; not the arms. An arm breaking will bring everything to a grinding halt and now you have a new project (making a new arm) instead of the current project you are working on. I use regular jute twine, which is 7lb line I believe, and I double it up once which can give plenty of tension on the blade. It’s not just a matter of tension on the blade though. It’s also that when you are pushing through insanely thick stock you are putting compression forces on the bottom of the arms (below the stretcher) and if there’s enough force, something will have to give. I have done this once going too aggressively (who has patience?) on 3” stock and it was a crazy loud CRACK! And things exploded. My initial thought was “no not an arm!!!!” But all the parts were fine. It was the string. It did what it was supposed to do and all I had to do was cut a new length of string and tie a not – I spent most of the couple minutes finding the bundle of twine.

    5) I did not use the Gramarcy hardware. I cut the heads off bolts, cut a slot, cut a groove (to keep it from twisting in the handle), drilled a hole, and epoxied them in. I use a bandsaw blade (a lifetime supply of blade material for $10) and drilled a corresponding hole at each end of the length I used. I cut a finish nail to hold it all together. If you look carefully I put a kink in the nails so they don’t fall out when the tension is removed, but I can still put them out if needed. One advantage of the Gramarcy pins is that they can accept blades that are 1/8” I think, whereas if you have to drill a hole 3/16” is about as small as you can go. They also look prettier, although I think you have less options for blades which might not really matter at all.

    6) I went through a couple blades trying to figure out what worked best. I settled on this one https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 which is 3/16, 10tpi, 0.25 thick. I learned the hard way not to go thinner than 0.25 because the blade will twist too much when you make a tight turn. I also learned that there’s no reason to go below 10tpi because I’m basically never ever making a finish cut with this thing. Anything visible will ultimate be hit with a file, or spokeshave, or sandpaper. Aggressive tpi and set both make it easier to cut faster and also make tighter turns. The only reason I see to go smaller than 10tpi is if cutting really thin stock, like 1/8”, or in some other very fragile situation. I’ve cut plenty of ¼” with no problems at 10tpi.

    turn1.jpgturn2.jpgturn3.jpg
    I second all of this. Especially the point on what string you use. I've broken a few strings, but never an arm. Who cares if the string breaks? Just replace it. You definitely don't want one of the arms to break, though.

  9. #9
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    Hey, thanks for the advice everyone. Chris, good lookin' saw, man. And very good info. I will take it all into consideration when I can start the project. I did buy the Gramercy pins and set of 3 blades. I forgot to gran the string, but looks like it's not necessary. I definitely have some 20lbs fly line backing around somewhere which should work well and is no doubt some obnoxious color.

    I initially didn't consider how lightweight you want a coping saw to be, but now I agree and see it as an ultimate consideration.

    I look forward to getting into this one.

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