Saw Blades And HSS References

Wow, Ned.. you're sounding very much like a PhD that can't hear anything that isn't spoken by another PhD.
Am I making stupid sounding muttering noises? It's everyday English, and
while I'm not an expert, it doesn't seem to mystify most folks I meet.
You ask me *again* to define flex, bend.. and what else did you need help understanding? This was a discussion, not an actual computer-modeled stress analysis of a crisis situation unfolding in front of our eyes. Parameters don't need to be defined in absolute terms.. common words usually suffice.

How was that not even remotely clear?

The subject material was never about selecting a good material for a mouth harp.
Yes, a bandsaw blade will spring back to it's original shape (after it breaks from the cracks originating in the tooth gullets).

Stress risers possibly into the backbone material, and lost teeth from a saw blade doesn't make a very efficiet cutting tool.
Blades with independent teeth are typically brazed carbide, and cracks in those gullets could mean that a larger pojectile may be released.

Are you not familiar with the blade travel on a horizontal bandsaw? Can you understand what continuous bending, flexing and maybe even twisting are taking place (with high blade tension and a feed rate into the stationary workpiece)?

No, not my thesis, see, because I'm not writing a thesis, and I haven't a clue why it seems you're taking the discussion as seriously as if getting a degree depended upon it. I could tolerate a few more degrees, there are only about 38 of 'em here today.
Still, it's not my unproven opinion, it was precisely the way a blade manufacturer illustrated and described the process of fabricating their blades, which I had also explained.

It depends on what you mean by bend, Ned. Are you referring to something which is not straight? By how many degrees, minutes and seconds are you suggesting? Please be concise, but no more than 64 pages, please.
Most anyone that's seen HSS snap would conclude that it's not going to bend, roll, conform to or wrap around a bandsaw wheel, but you're not sure about that. OK.

Hole saws are made from roll stock, much like bandsaw blades are, but don't believe that if you can't. But then I would have referred to the diameter, anyway. Maybe your holesaws are marked as radius though.

Or in your case, don't bend, be inflexible.
If the box states that the contents are HSS, then the contents couldn't possibly be anything else.
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On Mon, 1 Dec 2008 17:19:53 -0500, "Wild_Bill"

Sorry, Bill, I thought you might be willing to invest a little effort in learning something, when in fact it appears all you're interested in is hand waving arguments that support your preconceived notion that Starret, Lenox, Sandvik, et al are out to screw you.
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Just put plainly Ned, it was your nagging, bitchy approach.
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On Tue, 2 Dec 2008 10:59:17 -0500, "Wild_Bill"
Oh fercrissake, is this usenet or 7th grade?
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I think you read what you were replying to that time Ned.
Keep up the good work.
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On Tue, 02 Dec 2008 22:33:34 -0500, the infamous Ned Simmons

C: Both of the above.
Kids, please learn to play nicely with one another now. Thank you.
-- The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man. -- George Bernard Shaw
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    It is called "Godwin's Law", and it declares the thread in which the invocation of the term "Nazi" (or perhaps also Hitler) to be terminated. Good advice, I think. :-)
    Enjoy,         DoN.
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    [ ... ]

    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.
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A very worthwhile demonstration DoN. Not that I'm not unfamiliar with a drill missing a centerpunch mark, though.
I welcome your demonstration as a generous sharing of wisdom in a kindly fashion (which many of us in RCM have been accustomed to in your replies).
The part that remains a mystery to me is that HSS can be wrapped around bandsaw wheels under enough tension to produce a note when plucked, and then bend, deflect, flex and endure feed pressure into a workpiece while continuously running around in a loop (plus the added continuous twisting/straightening of a blade on a horizontal bandsaw).. a metal composition which is a material that I know snaps because it's brittle (as brittle as glass, for a rough estimation).
I can, however, fully understand that high carbon steel alloys would perform as described above, due to applying specific controllable levels of annealing (with anticipated results) to the materials.
For some, it seems to be beyond comprehension that anyone could possibly doubt a manufacturer's claim? I question things, that's all. Some do, some don't.
Your use of the term bend is highly suspect, BTW. Perhaps there is a code that could be developed, for times when it's convenient to use common words to express infinitely complex principles.
The conclusion that I've arrived at is that the teeth tips can be HSS, with interruptions between the teeth, so in some cases (brands, processes) the HSS is not a continuous, brittle strip enduring all the extreme conditions described above.
I think I mighta just learnt something agin, and I can only hope that doesn't happen again too soon.
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Example:- A 62.5 micron fibre optic fibre can bend to 1" radius (2"dia). It won't work properly because the light will tend to leak out, but it won't break. If you scale that up, you get a 25 thou thick sheet of glass being able to bend around a 15" diameter wheel without breaking.
Mark Rand RTFM
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Thanks for the example Mark. Do you know of any sources of online information (or manuals, books) that describe interfacing lenses to fiber optic cable/bundles not just for light transmission, but the fibrescope type applications?
Do you know of sources for a visual image optic cable approximately 0.68mm (.027") in diameter (enclosed in a sheath)?
I have a used fiberscope with a significant number of broken fibres. I'm wondering if the cable can be replaced, because I suspect that it's unlkely that it could be shortened or repaired. The light carrying fibres (a loose bundle) in the fibrescope are fairly coarse by comparison, looking more like they could actually be worked with by hand. The overall size of the cable is 3mm diameter x about 3.3M.
I can see a very small optical window/lens element at the tip, but I know nothing about the end termination methods involved with fibreoptics. The limited information that I've discovered about mating lenses in optical equipment involves Canadian balsam (?) or special grades of epoxies.
I haven't seen the interface at the eyepiece end yet, and I'm curious about how that's accomplished.
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    The fibers are typically two different glasses, selected for different index of refraction, one solid as the center, and the other hollow around the first. They are heated and the ends drawn apart, and the outer sheath collapses onto the inner core and they fuse together.
    I have seen rigid fiber optic devices which have been made by drawing down the center of a bundle, then cutting it in the middle, grinding polishing it. The result is a bundle which will enlarge or shrink an image. You can get these from Edmund Scientific or Edmund Optics (I forget which sells that) as demonstration pieces.
    You can also get ones where the fibers have been fused together and then twisted while still hot enough for the glass to bend, so the image is twisted 180 degrees.
    I've also seen fiber optic bundles fused together in a hex, then the center drawn out to make a smaller hex bundle, gathered with more hex bundles to farm a larger one, then drawn again through about three cycles -- then cut into thin slices and the inner core is removed by chemical etching leaving a honeycomb prior to coating (vacuum evaporation of metal) to form a channel for electrons as part of an image intensifier tube. This was called a microchannel, and was used to intensify the tiny signals which were common in serious astronomy. The electrons bouncing along the tubes from side to side, and accelerated by a voltage difference between the ends of the tubes, keep kicking out multiple additional electrons every time they hit, thus increasing the signal strength.
    Before microchannels -- larger intensifier tubes were made with rigid fiber optic bundles ground to a curve to match the electrostatic focusing in the tube, and ground to flat on the end -- joined to two other similar intensifier tubes by a silicone grease to couple the fiber images together.

    This is normally for joining the surfaces (usually curved) of different glasses to build a lens with just the needed index of refraction. You'll find a lot of these joints in the more complex camera lenses (faster and zoom lenses), and even the early Zeiss Tessar design had four elements -- the rear two cemented together, then a space for the iris diaphragm and shutter, and then two more elements which had an air gap between them -- and for folding cameras typically had the spacing between these two lens elements adjustable for focusing.

    Well ... typically the bundle for the image scopes is made by laying out fibers one at a time into a precise pattern, then fusing the ends (leaving the majority of the length loose for flexibility) and polishing the ends. The objective lens focuses the image on the flat polished surface at one end, and the eyepiece picks it up from the other end.
    Aside from the occasional broken fibers (which increase with use), there are also occasionally misplaced fibers which move a dot from one place to another.
    If *I* were to try to make an optimum quality image fiber bundle, what I would try to do is to lay the fibers in a loop and optically weld the ends together. (I've seen the device which does this with fiber optic lines used for telephone and network here in this neighborhood, and it is a neat device.) Anyway -- the welds would be scattered around the bundle, and the clamped group of fibers would be fused together (again two glass types -- the center for the optical signal, and the outer to protect the inner fiber and to fuse to adjacent ones). Once about two inches or so of fiber is fused into a rigid block, I would then diamond saw through the block and polish both ends to optically flat. This way, the fibers could not shift where the images are formed, and it does not really matter how much they shift in between, as long as they don't get broken. That's what the sheath is to prevent.
    ------------------------------------------------------------
    But I *think* that the original mention of how small a radius bend you can put in a glass fiber was to suggest that thin HSS (which you had said was as brittle as glass) could be bent to an equally tight radius if it was no thicker than the glass fiber's diameter.
    IIRC -- when someone in this thread mentioned solid HSS bandsaw blades, he did say that they were thinner than the usual carbon steel blades.
    And from bending which I have observed in a HSS (actually cobalt steel) parting blade with a maximum thickness of 1/8", I would say that that can be bent into a circle of about ten feet diameter or so. And that is a *lot* thicker than any bandsaw blade which I have ever used.
    Enjoy,         DoN.
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Your reply is a great one, and a large serving of stuff to digest, DoN. Thanks for including the detailed info concerning the glass fibers. I had no previous knowlege of the glass strands other than some of the early ones were made in tall tower-type structures at one point IIRC.
I hadn't realized the necessity to keep the individual fibers in correct order/orientation to reproduce a proper image until you mentioned it. Yeah.. I could see where that would matter, heh.
The ITI brand fiberscope I mentioned was apparently a fairly good one, when it was new. It's one of the flexible ones (3mm dia.) that can be articulated near the tip by two fine stranded wire cables tied to a knob on the hand/eyepiece/body. Clever little gizmo that works similarly to the earlier mechanical remote control automotive outside side/rear-view mirrors (but only two opposed directions, not four).
I took Mark's mention of bending a thin glass fiber to suggest it would be possible with thin HSS, as you mentioned. I was originally thinking in terms of the traditional process of producing bandsaw blades, which would require the cutting edge to be .025" or .035" thick (as those are common thicknesses of bandsaw blades). From there, the strip of hard material that's typically the hardened tooth material area on bandsaw blades, is wider than the thickness by many times (looks like about 5 times wider or more). The wheels on my 4x6 bandsaw are maybe 10" diameter, a port-a-band maybe smaller, but larger wheels on big saws naturally, and the possibility of running a brittle material around wheels with the numerous high forces mentioned earlier, seemed highly unlikely to me.
Previous to Mark's example, Robin had referred to a somewhat new technology developed by Starrett, where two thinner ribbons/foils of HSS are fused to/with the region near the edge of the supporting band material, resulting in a "steel on HSS sandwich" at one edge of the band. Then, when the tooth profiles are ground or milled into the edge of this region, it leaves less than the full width of the HSS ribbons/foils to bend/flex/twist etc. (or possibly even interrupted HSS-clad teeth, the image wasn't very detailed and the description not very specific).
Ed had mentioned Sandvik solid HSS power hacksaw blades being thick but somewhat bendy.
As per your suggestion of 1/8" cobalt making a wrap around maybe a 10' wheel.. An extremely long 1/8" thick solid HSS saw blade would've been handy for the cruise ship retrofitters that were assigned the task of adding a section in the center of a cruise ship, so they proceeded to cut the ship in half, and added the section. I don't know that the story was true, but there was an online story about it, maybe a couple of years ago.
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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 shit, I dunno why I even remembered that name correctly)
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On Sun, 30 Nov 2008 22:24:33 -0800 (PST), the infamous John Martin

--big snip--

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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That would be tri-metal, my good man.. to also include the braze filler.
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On Mon, 1 Dec 2008 10:32:34 -0500, the infamous "Wild_Bill"
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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On Sun, 30 Nov 2008 23:46:35 -0500, "Wild_Bill"

See http://www.doallsawing.com/saw_blades.aspx http://www.toolstop.co.uk/sandvik-3906-bi-metal-hacksaw-blades-12-x-18tpi-10-pack-p1869 http://www.milwaukeetool.com/webapp/wcs/stores/servlet/product_27_40028_-1_681811_192547_192327
I don't think these descriptions are marketing bullshit. The blades definitely perform.
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Thanks for the references, Don. Here is another high performance blade http://www.lenoxtools.com/enUS/Product/TRI-TECH_CT_.html
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