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.
--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html
"DoN. Nichols" wrote in message
...
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.
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