On Mon, 1 Dec 2008 10:32:34 -0500, the infamous "Wild_Bill"
scrawled the following:
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
[ ... ]
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
4) If it bends, are you going to say that the drill bit is not
5) Now -- with a solid carbide bit of the same size, it will
almost certainly break, but even it will bend a little before
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.
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
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
I think I mighta just learnt something agin, and I can only hope that
doesn't happen again too soon.
On Tue, 2 Dec 2008 10:51:37 -0500, "Wild_Bill"
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.
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
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
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.
I went searching for what in the HS steels could be welded successfully
to a med/high carbon backing. It looks like maybe all of the "M" HSS
grades could be joined without screwing up the carbides in the HSS part
and work OK.
None of the HS steels "like" to be normalized so there has to be some
provision for retarding the cooling after weld.
"T" series HSS austenitise at 2300 - 2375 (T9 and T15 a bit lower), "M"
series will go at ranges from 2150 - 2275. So either would have to be
hardened first, then tempered, then some provision for annealing
everything below the tooth edges would have to be made for a weld to be
Not all the processes could be done quickly, heating and quench would
occur in a furnace, then temper, then if the HSS section was in a coil
it would need to go back up to over 1400 but less than 1600 to be joined
with the backing. After welding (quickly, while everything is straight)
induction units could raise the temp to 1600 with the teeth in some heat
sink medium. Then the slow part... For a full anneal the temp drop
cannot exceed 40 degrees per hour, for a quick "partial" anneal up to
200 is possible. I don't see how it could be "hot" coiled into a furnace
for the anneal (remember the teeth have to stay under 1600).
I couldn't work a solution for welding both parts annealed then do the
hardening, quench and draw, and then anneal again (the HSS part).
I also first thought after you posted that it probably was one of the
"H" (hot work tool steels) but it appears only the "T" and "M" types
would have any abrasion advantage over plain old AISI 1060 blades with
induction hardened teeth.
I liked the "M" series because the are less brittle than the "T" and
have almost as much abrasion resistance (much cheaper too)..
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
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
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
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
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
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.
On Tue, 02 Dec 2008 22:33:34 -0500, the infamous Ned Simmons
scrawled the following:
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
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
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
As per your suggestion of 1/8" cobalt making a wrap around maybe a 10'
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.