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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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Saw Blades And HSS References
I'm wondering if someone can disprove or absolutely confirm that saw blades
do not consist of HSS. The term Bimetal or bi-metal doesn't absolutely mean that a blade consists partly of HSS, or that a blade could. Typically, all saw blades are bimetal, since the blade backing section is somewhat mild steel, and the tooth section is high carbon steel continuously welded along the length of the blade (including hole saws). Envision a coping saw blade (tooth section) welded to a steel backing section that makes up the overall width of the blade, such as a hacksaw, bandsaw or hole saw blade. When the paint is removed from some new saw blades, this is evident. The little knowlege that I'm certain of concerning HSS is that; 1. it doesn't bend (or flex repeatedly) 2. it can't be filed with an ordinary file When I see references to HSS saw blades, it sounds like a crock to me, although these references are common. -- WB .......... metalworking projects www.kwagmire.com/metal_proj.html |
#2
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Saw Blades And HSS References
On Nov 30, 11:46*pm, "Wild_Bill" wrote:
I'm wondering if someone can disprove or absolutely confirm that saw blades do not consist of HSS. What type of saw blade are you referring to? I'm assuming band saw, hacksaw, sawzall, hole saw, etc? The term Bimetal or bi-metal doesn't absolutely mean that a blade consists partly of HSS, or that a blade could. Are you telling us, or asking? I've only ever seen "bi-metal" referring to HSS teeth welded to a more flexible/less hard backing. Typically, all saw blades are bimetal, No. You can get HCS (high-carbon steel) blades, bi-metal blades and solid HSS blades (power hacksaw blades are commonly available as either bi-metal or solid HSS). since the blade backing section is somewhat mild steel, and the tooth section is high carbon steel continuously welded along the length of the blade (including hole saws). HSS is not simply high-carbon steel. There is a rather strict technical definition of what HSS is composed, and HSS is not simply high-carbon steel. Google is your friend. Envision a coping saw blade (tooth section) welded to a steel backing section that makes up the overall width of the blade, such as a hacksaw, bandsaw or hole saw blade. When the paint is removed from some new saw blades, this is evident. The little knowlege that I'm certain of concerning HSS is that; 1. it doesn't bend (or flex repeatedly) 2. it can't be filed with an ordinary file When I see references to HSS saw blades, it sounds like a crock to me, although these references are common. Can you provide specific examples? Perhaps we can take a look and advise you... Regards, Robin |
#3
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Saw Blades And HSS References
The quoted text didn't get marked as quoted GD Microsoft**** products
Robin's remarks are *** wrote in message ... On Nov 30, 11:46 pm, "Wild_Bill" wrote: I'm wondering if someone can disprove or absolutely confirm that saw blades do not consist of HSS. *** What type of saw blade are you referring to? I'm assuming band saw, hacksaw, sawzall, hole saw, etc? There have been countless references to all types of HSS saw blades here in RCM. The term Bimetal or bi-metal doesn't absolutely mean that a blade consists partly of HSS, or that a blade could. *** Are you telling us, or asking? I'm saying this as a deterrent to the too-common usage of HSS in blades. *** I've only ever seen "bi-metal" referring to HSS teeth welded to a more flexible/less hard backing. Are you referring to individual HSS teeth welded to steel, such as a circular saw blade? (commonly misrepresented as a skilsaw) Circular saw blades that have carbide teeth brazed to a mild steel disk, are common, but I'm unaware of other common saw blades with individual brazed teeth. Are you saying HSS bends? As in HSS bandsaw blade? HSS hole saw blade formed into a circle? I disagree. If you're the same Robin that's been partcipating in RCM discussions for years (haven't seen you here for a while), I can't believe that you haven't seen a broken HSS cutting tool, such as a HSS cutoff/parting tool. Generally, broken cutoff/parting tools happen when they are improperly supported or improperly loaded (side pressure), snap.. as in not flexible. Typically, all saw blades are bimetal, *** No. You can get HCS (high-carbon steel) blades, bi-metal blades and solid HSS blades (power hacksaw blades are commonly available as either bi-metal or solid HSS). I'd like to see an example of a solid HSS saw blade. The only ones I'm aware of are slitting blades (small like a Dremel saw, or larger like a slitting blade typically for use on a mill). And when they are flexed, they snap, which is my primary point. since the blade backing section is somewhat mild steel, and the tooth section is high carbon steel continuously welded along the length of the blade (including hole saws). *** HSS is not simply high-carbon steel. There is a rather strict technical definition of what HSS is composed, and HSS is not simply high-carbon steel. Google is your friend. I'm aware that HSS is not HCS, I tried to make that distinction by typing out high carbon steel when I was referring to high carbon steel, I thought that was obvious. Envision a coping saw blade (tooth section) welded to a steel backing section that makes up the overall width of the blade, such as a hacksaw, bandsaw or hole saw blade. When the paint is removed from some new saw blades, this is evident. The little knowlege that I'm certain of concerning HSS is that; 1. it doesn't bend (or flex repeatedly) 2. it can't be filed with an ordinary file When I see references to HSS saw blades, it sounds like a crock to me, although these references are common. *** Can you provide specific examples? Perhaps we can take a look and advise you... *** Regards, *** Robin A specific example woud be a slitting saw. Properly supported and properly loaded in the direction of a cut, they perform fantasticlly. However when flexed, they snap. A HSS bandsaw would not flex. It couldn't be formed into a circle for welding without breaking the HSS "tooth section". The same goes for hole saw fabrication. A HSS hacksaw blade would snap if not supported or used very cautiously, loaded as lightly as a jewelers saw blade, essentially. Summation: HSS does not bend. Thin cross-sections of HSS will snap. -- WB .......... metalworking projects www.kwagmire.com/metal_proj.html |
#4
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Saw Blades And HSS References
"Wild_Bill" wrote in message ... snip I'd like to see an example of a solid HSS saw blade. The only ones I'm aware of are slitting blades (small like a Dremel saw, or larger like a slitting blade typically for use on a mill). And when they are flexed, they snap, which is my primary point. I have two boxes of Sandvik HSS power hacksaw blades here, HSS through and through, but they're quite thick and they're not expected to flex in service. However, they do flex somewhat -- I don't know how much because I've never broken one. But they are a bit bendy. It may be they're tempered differently for use as a sawblade than they are for a lathe cutting tool. -- Ed Huntress |
#5
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Saw Blades And HSS References
Thanks, Ed. I was interested in what you're perspective would be. I saw a
Starrett Redline 18" power hacksaw blade advertised as HSS (though not specifically stated as solid HSS), about $22 each US, at Ace Hardware's online store. Power hacksaw blade duty is a long way from a flexing bandsaw blade, and Starrett makes the claim that their Redline bandsaw blades are also HSS. -- WB .......... metalworking projects www.kwagmire.com/metal_proj.html "Ed Huntress" wrote in message ... "Wild_Bill" wrote in message ... snip I'd like to see an example of a solid HSS saw blade. The only ones I'm aware of are slitting blades (small like a Dremel saw, or larger like a slitting blade typically for use on a mill). And when they are flexed, they snap, which is my primary point. I have two boxes of Sandvik HSS power hacksaw blades here, HSS through and through, but they're quite thick and they're not expected to flex in service. However, they do flex somewhat -- I don't know how much because I've never broken one. But they are a bit bendy. It may be they're tempered differently for use as a sawblade than they are for a lathe cutting tool. -- Ed Huntress |
#6
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Saw Blades And HSS References
On Dec 1, 1:22*am, "Wild_Bill" wrote:
Summation: HSS does not bend. Thin cross-sections of HSS will snap. STOP saying "does not bend" - it is fully and completely wrong. Get an indicator and a lever of some type and watch. Even carbide will bend to some degree without shattering. Otherwise, your cutting tools would shatter as soon as they touched the work. And that's ENTIRELY enough about that. Take a look at http://www.starrett.com/pages/934_bi...technology.cfm The HSS strip is welded onto the flexible backing, and then the teeth are ground into the blade. The grind SEEMS to finish past the weld boundary, meaning there are individual HSS teeth created. The grind likely occurs before the coil is wound up again, thus, the HSS strip is never coiled while hard. If you really want a good answer, call Starrett's band saw blade facility at 336-789-5141 and ask for "someone in technical". Don't make accusations and don't patronize these people - all they do is make really good band saw blades! ULTIMATELY you believe all these manufacturers are basically lying. Well, run a good quality hole saw at HSS surface speed and see if it melts. Simple. No magic. Absolute answer. NO NEED to post one more reply until you've done this or similar. Regards, Robin |
#7
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Saw Blades And HSS References
Until I complete my new assignment Robin, I only have this to clarify "does
not bend" = not easily bent.. in an arc.. roughly estimating the diameter of a bandsaw wheel (or radius for you physicists out there). But also, When the discussion refers to bandsaw blades numerous times, what is so difficult about understanding "bend"? When you've experienced HSS snapping, were you attempting to do something to it other than bending? Flexing? Twisting? Just aggravating it maybe? The method of bandsaw/holesaw and straight saw blade fabrication I referred to earlier was the Traditional weld or laser bonding process, as I had described.. adding a hard cutting material to the edge of a softer, flexible backbone. You have partially answered some of my question, but then based it upon your own assumptions.. The HSS strip is welded onto the flexible backing, and then the teeth are ground into the blade. Or the teeth are milled. Your words: SEEMS to, followed by likely occurs OK, I shall not be patronizing because you said not to. The Starrett page doesn't state that the "new" technology (at that time, see article 2005 issue of Modern Metals) Bi-Metal Unique product blade material is available in coil (roll was the wrong word) stock, only that straight blades and portable band saw blades are available. So what level of real production performance are you seeing with this Bi-Metal Unique product? Seems odd to exclude coil (not roll) stock. Maybe the stuff can't be welded with a common blade welder. When I looked for coil stock of the HSS with 8% Cobalt Bi-metal Unique, it only showed portable bandsaw coil stock for the Flex-Back product, not the Bi-Metal Unique product. But then a footnote states.. bi-metal unique and M42 blades also available 100 per box (if they didn't mean 100' per box). It's all highly confusing, good thing that they list phone numbers though. What I've said is I think HSS bandsaw blades were created in a marketing department or firm (based on my experiences that HSS does not bend (which means not easily bent.. in an arc.. roughly estimating the diameter of a bandsaw wheel). The reason crapVista Window**** products Mail isn't quoting the couple of random messages is because the posters are commenting thru TheGoogGroups, it appears. -- WB .......... metalworking projects www.kwagmire.com/metal_proj.html wrote in message ... On Dec 1, 1:22 am, "Wild_Bill" wrote: Summation: HSS does not bend. Thin cross-sections of HSS will snap. STOP saying "does not bend" - it is fully and completely wrong. Get an indicator and a lever of some type and watch. Even carbide will bend to some degree without shattering. Otherwise, your cutting tools would shatter as soon as they touched the work. And that's ENTIRELY enough about that. Take a look at http://www.starrett.com/pages/934_bi...technology.cfm The HSS strip is welded onto the flexible backing, and then the teeth are ground into the blade. The grind SEEMS to finish past the weld boundary, meaning there are individual HSS teeth created. The grind likely occurs before the coil is wound up again, thus, the HSS strip is never coiled while hard. If you really want a good answer, call Starrett's band saw blade facility at 336-789-5141 and ask for "someone in technical". Don't make accusations and don't patronize these people - all they do is make really good band saw blades! ULTIMATELY you believe all these manufacturers are basically lying. Well, run a good quality hole saw at HSS surface speed and see if it melts. Simple. No magic. Absolute answer. NO NEED to post one more reply until you've done this or similar. Regards, Robin |
#8
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Saw Blades And HSS References
On Dec 1, 6:57*pm, "Wild_Bill" wrote:
While there are many points in your message to which I would love to respond, I have only one request: State your question in one sentence. Regards, Robin |
#9
Posted to rec.crafts.metalworking
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Saw Blades And HSS References
On Nov 30, 11:46*pm, "Wild_Bill" wrote:
I'm wondering if someone can disprove or absolutely confirm that saw blades do not consist of HSS. The term Bimetal or bi-metal doesn't absolutely mean that a blade consists partly of HSS, or that a blade could. Typically, all saw blades are bimetal, since the blade backing section is somewhat mild steel, and the tooth section is high carbon steel continuously welded along the length of the blade (including hole saws). Envision a coping saw blade (tooth section) welded to a steel backing section that makes up the overall width of the blade, such as a hacksaw, bandsaw or hole saw blade. When the paint is removed from some new saw blades, this is evident. The little knowlege that I'm certain of concerning HSS is that; 1. it doesn't bend (or flex repeatedly) 2. it can't be filed with an ordinary file When I see references to HSS saw blades, it sounds like a crock to me, although these references are common. -- WB ......... metalworking projectswww.kwagmire.com/metal_proj.html I guess I can disprove it, Bill. I have hack saw blades that are solid HSS. I have hack saw blades that are bi-metal - HSS edge with alloy or carbon steel back. And I have hack saw blades that are solid carbon steel. I have band saw blades that are bi-metal. I have band saw blades that are solid carbon steel - same steel from teeth to back. I don't happen to have any solid HSS band saw blades, but they are made. I have circular saws that are solid HSS. I have circular saws that are solid carbon or alloy steel. I don't recall seeing any bi-metal circular saws, but that doesn't mean they don't exist. There are bi-metal hole saws, and solid carbon or alloy steel hole saws. Coping saws, hand saws and other human-powered woodworking saws are typically carbon steel, but who knows what might be available? You are correct that The term Bimetal or bi-metal doesn't absolutely mean that a blade consists partly of HSS, or that a blade could. But if you check those that are available, you'll find that that is exactly what they are. All saw blades are not bi-metal. As I've listed, some are, but others are solid HSS or solid carbon or alloy steel. Your knowledge concerning HSS is a bit off too, I'm afraid. It can flex, and it can be filed. Not in the fully hardened state, maybe, and not as well as some other steels, maybe, but it can. John Martin |
#10
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Saw Blades And HSS References
Thanks for your input, John. I have seen blade manufacturers state that
their blades are HSS, and often label them as HSS, but I'm not aware that any version of HSS is soft enough to flex. Because a package states that a blade is HSS isn't convincing to me. A commonly available HSS in it's annealed state is the shank section of HSS twist drills. In the annealed state HSS doesn't make a good cutting tool for metalworking. I'm fairly certain that the annealed shank of a drill or reamer wouldn't bend before breaking, such as a Cleveland or other quality genuine HSS drill, not HFeuroasia-somewhere cheese steel. I wonder how many HSMs have found a way to bend or reshape a HSS drill or reamer shank. I would suggest that solid HSS hacksaw blades would not flex before snapping. A solid HSS hacksaw blade would have the brittle characteristics of a HSS cutoff/parting blade/tool, with the extra fragility of having tooth gullets ground into the edge. Or why wouldn't it? I can't recall ever hearing of a problem where a cutoff/parting tool became bent.. they either snap (or chip) or they don't. You might be implying that a 100+ inch length (of thin cross-section or any other shape) of solid HSS could be formed into a circle to form a bandsaw blade, then tensioned and run continuously in a loop, while applying pressure to the blade edge. I just wonder how you accept that this is logical, that's all. -- WB .......... metalworking projects www.kwagmire.com/metal_proj.html "John Martin" wrote in message ... On Nov 30, 11:46 pm, "Wild_Bill" wrote: I'm wondering if someone can disprove or absolutely confirm that saw blades do not consist of HSS. The term Bimetal or bi-metal doesn't absolutely mean that a blade consists partly of HSS, or that a blade could. Typically, all saw blades are bimetal, since the blade backing section is somewhat mild steel, and the tooth section is high carbon steel continuously welded along the length of the blade (including hole saws). Envision a coping saw blade (tooth section) welded to a steel backing section that makes up the overall width of the blade, such as a hacksaw, bandsaw or hole saw blade. When the paint is removed from some new saw blades, this is evident. The little knowlege that I'm certain of concerning HSS is that; 1. it doesn't bend (or flex repeatedly) 2. it can't be filed with an ordinary file When I see references to HSS saw blades, it sounds like a crock to me, although these references are common. -- WB ......... metalworking projectswww.kwagmire.com/metal_proj.html I guess I can disprove it, Bill. I have hack saw blades that are solid HSS. I have hack saw blades that are bi-metal - HSS edge with alloy or carbon steel back. And I have hack saw blades that are solid carbon steel. I have band saw blades that are bi-metal. I have band saw blades that are solid carbon steel - same steel from teeth to back. I don't happen to have any solid HSS band saw blades, but they are made. I have circular saws that are solid HSS. I have circular saws that are solid carbon or alloy steel. I don't recall seeing any bi-metal circular saws, but that doesn't mean they don't exist. There are bi-metal hole saws, and solid carbon or alloy steel hole saws. Coping saws, hand saws and other human-powered woodworking saws are typically carbon steel, but who knows what might be available? You are correct that The term Bimetal or bi-metal doesn't absolutely mean that a blade consists partly of HSS, or that a blade could. But if you check those that are available, you'll find that that is exactly what they are. All saw blades are not bi-metal. As I've listed, some are, but others are solid HSS or solid carbon or alloy steel. Your knowledge concerning HSS is a bit off too, I'm afraid. It can flex, and it can be filed. Not in the fully hardened state, maybe, and not as well as some other steels, maybe, but it can. John Martin |
#11
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Saw Blades And HSS References
On Dec 1, 2:15*am, "Wild_Bill" wrote:
Thanks for your input, John. I have seen blade manufacturers state that their blades are HSS, and often label them as HSS, but I'm not aware that any version of HSS is soft enough to flex. Because a package states that a blade is HSS isn't convincing to me. A commonly available HSS in it's annealed state is the shank section of HSS twist drills. In the annealed state HSS doesn't make a good cutting tool for metalworking. I'm fairly certain that the annealed shank of a drill or reamer wouldn't bend before breaking, such as a Cleveland or other quality genuine HSS drill, not HFeuroasia-somewhere cheese steel. I wonder how many HSMs have found a way to bend or reshape a HSS drill or reamer shank. I would suggest that solid HSS hacksaw blades would not flex before snapping. A solid HSS hacksaw blade would have the brittle characteristics of a HSS cutoff/parting blade/tool, with the extra fragility of having tooth gullets ground into the edge. Or why wouldn't it? I can't recall ever hearing of a problem where a cutoff/parting tool became bent.. they either snap (or chip) or they don't. You might be implying that a 100+ inch length (of thin cross-section or any other shape) of solid HSS could be formed into a circle to form a bandsaw blade, then tensioned and run continuously in a loop, while applying pressure to the blade edge. I just wonder how you accept that this is logical, that's all. -- WB - - Show quoted text - My brother-in-law manufactures band saw, hack saw and hole saw blades. When the catalog says a blade is HSS, the package says it is HSS, and it says on the blade that it is HSS, I tend to believe that it is HSS. Maybe I'm too trusting, though. Their Redstripe hack saw blades are solid HSS. They do flex, but not as much as their bi-metal or carbon steel blades - which is why they recommend them where the work is firmly held and the blade is not subject to much twisting. They will snap if flexed too much. They do not currently list a solid HSS band saw blade. They had one in their 1985 catalog, which I have in front of me, but do not offer it today. It was a thin blade - .020" or .025" against the .035" of their typical bi-metal blades. Now, this next part is just my own guess, because I don't in any way speak for them. I believe that the solid HSS band saw blades were, like the solid HSS hack saw blades, more subject to breakage from twisting and flexing than the bi-metal blades. The bi-metal blades were more subject to stripping teeth, although welding technology has improved. But again, that's all just my guess. Take almost any carbon steel hack saw blade. Bend it double, and roll the bend around a bit. Listen carefully while you do it, and you just may hear the cracking sounds as the blade cracks at the gullets. Without cracking completely across. How can it do that? Since it's solid carbon steel, shouldn't the entire blade by your logic have the brittle characteristics that the tooth edge does? Shouldn't it be impossible to make a spring from the very same material you make a brittle cutting blade from? But you can do that, can't you? So, maybe it's similarly possible to heat treat HSS to get a wide range of characteristics, just as you can with the high carbon steel. I accept that it is logical because it is, to me, just that. Logical. Not sure what it might take to convince you, though. John Martin |
#12
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Saw Blades And HSS References
I was following you right along John, until you brought up the high carbon
steel hypothesis. *** Since it's solid carbon steel, shouldn't the entire blade by your logic have the brittle characteristics that the tooth edge does? High carbon steel is easily annealed, but HSS not so much. As I said earlier, the saw blade backing (backbone?) material is generally a milder steel. It could be similar to steel banding material. It flexes very easily and doesn't work harden. Springs should not, and aren't usually made from brittle materials, because they wouldn't serve their purpose. Generally, when a spring is bent by hand for example, it bends (until the radius becomes too small, such as around the corner/edge of a vise jaw). We seem to be approaching the area of modulus of elasticity, which isn't at all what I was referring to, as far as HSS being suitable (or even possible) for use as a flexible blade material, such as a bandsaw blade. I'm no metallurgist, but if HSS has a MoE, I'd guess that it wouldn't even resemble mild steel, and I'm guessing that it would be significantly different than high carbon steel and/or spring steel. I remember using some hacksaw blades decades ago, that would snap completely thru their width, and I believe they were high carbon steel entirely, with very little or no annealing of the blade back material, so it was as brittle (or nearly as brittle) as the tooth area. I suspect that these may have been the cheapest blades available at that time, and I haven't encountered any hacksaw blades made like that, since then. Modern, commonly available, general use hacksaw blades are typically a softer/mild steel back material with a hardened tooth area (generally a welded section added to the mild steel back material by continuous welding). But it's highly unlikely that the hard tooth section is actually HSS, as HSS does not bend. To offer an answer to the question "wouldn't/can't the cracking be heard as the blade is bent".. well yes, and that's because the tooth area is a strip of high carbon steel mated to a flexible back material, but the tooth strip/area is not likely to be HSS, because solid HSS doesn't bend. So what good would a bandsaw blade be, if all the teeth cracked at the tooth gullets? I don't know if HSS can be combined with high carbon steel to create a HSS alloy, but if it can, my swag would be that the percentage amount of HSS would be small. I strongly suspect that the concept of HSS bandsaw blades (or any other flexible HSS blade) was created in a marketing department or firm. -- WB .......... metalworking projects www.kwagmire.com/metal_proj.html "John Martin" wrote in message ... On Dec 1, 2:15 am, "Wild_Bill" wrote: My brother-in-law manufactures band saw, hack saw and hole saw blades. When the catalog says a blade is HSS, the package says it is HSS, and it says on the blade that it is HSS, I tend to believe that it is HSS. Maybe I'm too trusting, though. Their Redstripe hack saw blades are solid HSS. They do flex, but not as much as their bi-metal or carbon steel blades - which is why they recommend them where the work is firmly held and the blade is not subject to much twisting. They will snap if flexed too much. They do not currently list a solid HSS band saw blade. They had one in their 1985 catalog, which I have in front of me, but do not offer it today. It was a thin blade - .020" or .025" against the .035" of their typical bi-metal blades. Now, this next part is just my own guess, because I don't in any way speak for them. I believe that the solid HSS band saw blades were, like the solid HSS hack saw blades, more subject to breakage from twisting and flexing than the bi-metal blades. The bi-metal blades were more subject to stripping teeth, although welding technology has improved. But again, that's all just my guess. Take almost any carbon steel hack saw blade. Bend it double, and roll the bend around a bit. Listen carefully while you do it, and you just may hear the cracking sounds as the blade cracks at the gullets. Without cracking completely across. How can it do that? Since it's solid carbon steel, shouldn't the entire blade by your logic have the brittle characteristics that the tooth edge does? Shouldn't it be impossible to make a spring from the very same material you make a brittle cutting blade from? But you can do that, can't you? So, maybe it's similarly possible to heat treat HSS to get a wide range of characteristics, just as you can with the high carbon steel. I accept that it is logical because it is, to me, just that. Logical. Not sure what it might take to convince you, though. John Martin |
#13
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Saw Blades And HSS References
Wild_Bill wrote:
Never considered the subject??? (snip) Springs should not, and aren't usually made from brittle materials, because they wouldn't serve their purpose. Springs (old days) = AISI 1050R to 1090, and can be tempered from tough(30-45Rc) to brittle (45-60Rc). Leaf springs are often in the 45 to 50 range). Yield and tensile are essentially the same as quenched. Modern, commonly available, general use hacksaw blades are typically a softer/mild steel back material with a hardened tooth area (generally a welded section added to the mild steel back material by continuous welding). I'll have to check my ASM lit, (I just have the HT lit at home), for materials commonly used for hack/band saw blades. But it's highly unlikely that the hard tooth section is actually HSS, as HSS does not bend. (snip) I don't know if HSS can be combined with high carbon steel to create a HSS alloy, You'd be right, different melt point, molecule (face/cubic centered), different structure, etc. etc. It would be near impossible to join by fusion weld. I strongly suspect that the concept of HSS bandsaw blades (or any other flexible HSS blade) was created in a marketing department or firm. Probably right, the Bi-metal is more likely done using one of the "S" or "H" type tool steels. Matt |
#14
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Saw Blades And HSS References
On Mon, 1 Dec 2008 05:47:04 -0500, "Wild_Bill"
wrote: I was following you right along John, until you brought up the high carbon steel hypothesis. *** Since it's solid carbon steel, shouldn't the entire blade by your logic have the brittle characteristics that the tooth edge does? High carbon steel is easily annealed, but HSS not so much. As I said earlier, the saw blade backing (backbone?) material is generally a milder steel. It could be similar to steel banding material. It flexes very easily and doesn't work harden. Springs should not, and aren't usually made from brittle materials, because they wouldn't serve their purpose. Generally, when a spring is bent by hand for example, it bends (until the radius becomes too small, such as around the corner/edge of a vise jaw). We seem to be approaching the area of modulus of elasticity, which isn't at all what I was referring to, as far as HSS being suitable (or even possible) for use as a flexible blade material, such as a bandsaw blade. I'm no metallurgist, but if HSS has a MoE, I'd guess that it wouldn't even resemble mild steel, and I'm guessing that it would be significantly different than high carbon steel and/or spring steel. The modulus of elasticity of all those alloys, in fact all steels, falls in a very narrow range. But that has little to do with this discussion. I remember using some hacksaw blades decades ago, that would snap completely thru their width, and I believe they were high carbon steel entirely, with very little or no annealing of the blade back material, so it was as brittle (or nearly as brittle) as the tooth area. I suspect that these may have been the cheapest blades available at that time, and I haven't encountered any hacksaw blades made like that, since then. Modern, commonly available, general use hacksaw blades are typically a softer/mild steel back material with a hardened tooth area (generally a welded section added to the mild steel back material by continuous welding). But it's highly unlikely that the hard tooth section is actually HSS, as HSS does not bend. You need to clarify what you mean by "bend." Clearly HSS can bend without breaking, just like any metal, as long as its ultimate tensile strength is not exceeded. What's different about fully hard HSS, compared to materials you might consider "springier" (using that term very loosely), is that the difference between its yield and ultimate tensile is very small. In other words, there's not much difference between how much it can bend and spring back and the point where it will break, i.e., it's brittle. The difference between carbon steel hacksaw blades vs. HSS bimetal blades when cutting difficult materials (SS, alloy steels) is remarkable. Get yourself a carbon blade from a good manufacturer and a Lenox (sorry, John g) bimetal blade and try cutting an allen wrench in half. I doubt you'll make much of a dent with the carbon blade. The bimetal blade will be a bit worse for the wear, but it will cut the wrench. The edge on good bimetal hole saws is clearly HSS -- otherwise the speed required to run a 3" hole saw in steel without instantly dulling the teeth would be abysmally slow. If you've ever tried using a carbon steel twist drill in steel, you'll know what I mean. To offer an answer to the question "wouldn't/can't the cracking be heard as the blade is bent".. well yes, and that's because the tooth area is a strip of high carbon steel mated to a flexible back material, but the tooth strip/area is not likely to be HSS, because solid HSS doesn't bend. There'd be no good reason to weld a carbon steel edge to a carbon steel back. If the goal is a hard edge and softer back, then differential hardening/tempering of the blade will accomplish that, and is exactly what's done for carbon steel bandsaw blades. So what good would a bandsaw blade be, if all the teeth cracked at the tooth gullets? As long as the teeth stay attached to the back, I don't see that the cracks would be a problem. -- Ned Simmons |
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Saw Blades And HSS References
On 2008-12-01, Wild_Bill wrote:
[ ... ] To offer an answer to the question "wouldn't/can't the cracking be heard as the blade is bent".. well yes, and that's because the tooth area is a strip of high carbon steel mated to a flexible back material, but the tooth strip/area is not likely to be HSS, because solid HSS doesn't bend. O.K. I propose another experiment: 1) Take about a #1 drill bit, and drill into mild steel just enough to make a cone almost the diameter of the drill bit. 2) Then replace it with a #50 known HSS drill bit, shift the workpiece just enough so the drill bit's point comes down on the sloped surface of the previous cone. (I'm assuming a drill press with little or no perceptible slop in the bearings). 3) Turn on the drill press, and bring the bit down into contact, watching it closely (with ey protection, of course). When the bit contacts the cone, does the bit proceed to drill right below its contact point, or does it bend towards the center of the cone? 4) If it bends, are you going to say that the drill bit is not HSS? 5) Now -- with a solid carbide bit of the same size, it will almost certainly break, but even it will bend a little before breaking. Enjoy, DoN. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
#16
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Saw Blades And HSS References
In comaprison to John's suggestion to flex a hacksaw blade below,
I'm fairly certain what would happen if I were to take a 1/8"x1/2" (cross-sectional dimension) x 4" length of HSS, which could be a cutoff/parting blade, and attempt to bow it so that it deflects even 1/8" in the center. Uri Geller could do it. (Ahhh ****, I dunno why I even remembered that name correctly) -- WB .......... metalworking projects www.kwagmire.com/metal_proj.html "John Martin" wrote in message ... snippings Take almost any carbon steel hack saw blade. Bend it double, and roll the bend around a bit. Listen carefully while you do it, and you just may hear the cracking sounds as the blade cracks at the gullets. Without cracking completely across. How can it do that? Since it's solid carbon steel, shouldn't the entire blade by your logic have the brittle characteristics that the tooth edge does? Shouldn't it be impossible to make a spring from the very same material you make a brittle cutting blade from? But you can do that, can't you? So, maybe it's similarly possible to heat treat HSS to get a wide range of characteristics, just as you can with the high carbon steel. I accept that it is logical because it is, to me, just that. Logical. Not sure what it might take to convince you, though. John Martin |
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Saw Blades And HSS References
On Sun, 30 Nov 2008 22:24:33 -0800 (PST), the infamous John Martin
scrawled the following: metalworking projectswww.kwagmire.com/metal_proj.html I guess I can disprove it, Bill. --big snip-- I have circular saws that are solid HSS. I have circular saws that are solid carbon or alloy steel. I don't recall seeing any bi-metal circular saws, but that doesn't mean they don't exist. I use only bi-metal circular saw blades. They're soft-steel centered with carbide tips brazed on. -- The only difference between a rut and a grave...is in their dimensions. -- Ellen Glasglow |
#18
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Saw Blades And HSS References
That would be tri-metal, my good man.. to also include the braze filler.
-- WB .......... metalworking projects www.kwagmire.com/metal_proj.html "Larry Jaques" wrote in message ... On Sun, 30 Nov 2008 22:24:33 -0800 (PST), the infamous John Martin scrawled the following: metalworking projectswww.kwagmire.com/metal_proj.html I guess I can disprove it, Bill. --big snip-- I have circular saws that are solid HSS. I have circular saws that are solid carbon or alloy steel. I don't recall seeing any bi-metal circular saws, but that doesn't mean they don't exist. I use only bi-metal circular saw blades. They're soft-steel centered with carbide tips brazed on. -- The only difference between a rut and a grave...is in their dimensions. -- Ellen Glasglow |
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Saw Blades And HSS References
On Mon, 1 Dec 2008 10:32:34 -0500, the infamous "Wild_Bill"
scrawled the following: That would be tri-metal, my good man.. to also include the braze filler. Nah, metals in quantities of less than 1% don't count. -- The only difference between a rut and a grave...is in their dimensions. -- Ellen Glasglow |
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Saw Blades And HSS References
On Sun, 30 Nov 2008 23:46:35 -0500, "Wild_Bill"
wrote: I'm wondering if someone can disprove or absolutely confirm that saw blades do not consist of HSS. The term Bimetal or bi-metal doesn't absolutely mean that a blade consists partly of HSS, or that a blade could. Typically, all saw blades are bimetal, since the blade backing section is somewhat mild steel, and the tooth section is high carbon steel continuously welded along the length of the blade (including hole saws). Envision a coping saw blade (tooth section) welded to a steel backing section that makes up the overall width of the blade, such as a hacksaw, bandsaw or hole saw blade. When the paint is removed from some new saw blades, this is evident. The little knowlege that I'm certain of concerning HSS is that; 1. it doesn't bend (or flex repeatedly) 2. it can't be filed with an ordinary file When I see references to HSS saw blades, it sounds like a crock to me, although these references are common. See http://www.doallsawing.com/saw_blades.aspx http://www.toolstop.co.uk/sandvik-39...-10-pack-p1869 http://www.milwaukeetool.com/webapp/..._192547_192327 I don't think these descriptions are marketing bull****. The blades definitely perform. |
#21
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Saw Blades And HSS References
Thanks for the references, Don. Here is another high performance blade
http://www.lenoxtools.com/enUS/Produ...-TECH_CT_.html -- WB .......... metalworking projects www.kwagmire.com/metal_proj.html "Don Foreman" wrote in message ... On Sun, 30 Nov 2008 23:46:35 -0500, "Wild_Bill" wrote: I'm wondering if someone can disprove or absolutely confirm that saw blades do not consist of HSS. The term Bimetal or bi-metal doesn't absolutely mean that a blade consists partly of HSS, or that a blade could. Typically, all saw blades are bimetal, since the blade backing section is somewhat mild steel, and the tooth section is high carbon steel continuously welded along the length of the blade (including hole saws). Envision a coping saw blade (tooth section) welded to a steel backing section that makes up the overall width of the blade, such as a hacksaw, bandsaw or hole saw blade. When the paint is removed from some new saw blades, this is evident. The little knowlege that I'm certain of concerning HSS is that; 1. it doesn't bend (or flex repeatedly) 2. it can't be filed with an ordinary file When I see references to HSS saw blades, it sounds like a crock to me, although these references are common. See http://www.doallsawing.com/saw_blades.aspx http://www.toolstop.co.uk/sandvik-39...-10-pack-p1869 http://www.milwaukeetool.com/webapp/..._192547_192327 I don't think these descriptions are marketing bull****. The blades definitely perform. |
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