"Jon Elson" wrote in message
...
Ed Huntress wrote:



g It's too bad that term has stuck. I've talked to a lot of people over
the years who don't realize that "solid carbide" actually is a sintered
material, with tungsten carbide and tantalum carbide particles cemented
together with cobalt and/or other metals.

The genesis of the non-solid variety, as far as I know, is that in the
beginning, there
were cutters made with steel shanks and the cutter was welded on, probably
during the sintering process. I know this was true with carbide circuit
board drills. I'm sure nobody makes them this way anymore, at least in
modest sizes up to a couple inches diameter.

Jon

Right, brazed-tip cutters were probably what people were contrasting "solid"
carbide cutters with, when the terms were first in use.

Just for future reference, though, they wouldn't be welded. Tungsten carbide
with a cobalt binder is usually liquid-phase sintered at around 2700 deg. F.
That's the melting temperature of most steel. You'd have a carbide tip on a
steel puddle. g

They brazed the tips on. I have some old ones from the 1930s that were
brazed with copper. Most are brazed with bronze (actually, brass). Today,
they make special-purpose high-temperature silver braze for the application.

--
Ed Huntress

"Ed Huntress" wrote in message
...

"Jon Elson" wrote in message
...
Ed Huntress wrote:



g It's too bad that term has stuck. I've talked to a lot of people
over
the years who don't realize that "solid carbide" actually is a sintered
material, with tungsten carbide and tantalum carbide particles cemented
together with cobalt and/or other metals.

The genesis of the non-solid variety, as far as I know, is that in the
beginning, there
were cutters made with steel shanks and the cutter was welded on,
probably
during the sintering process. I know this was true with carbide circuit
board drills. I'm sure nobody makes them this way anymore, at least in
modest sizes up to a couple inches diameter.

Jon

Right, brazed-tip cutters were probably what people were contrasting
"solid" carbide cutters with, when the terms were first in use.

Just for future reference, though, they wouldn't be welded. Tungsten
carbide with a cobalt binder is usually liquid-phase sintered at around
2700 deg. F. That's the melting temperature of most steel. You'd have a
carbide tip on a steel puddle. g

They brazed the tips on. I have some old ones from the 1930s that were
brazed with copper. Most are brazed with bronze (actually, brass). Today,
they make special-purpose high-temperature silver braze for the
application.



Yes silver solder works well.

And a copper or brass shim is often placed between the steel and the carbide
to reduce stresses induced by cooling due to their unequal thermal expansion
rates.