Chris is right to emphasize using carbide...or any of the harder and/or
smoother surface materials...they are all better for seismo pivot
material than run of the mill steel and iron rods.  The pivot itself is the
"heart" of your seismo enertia mass response working
reasonably well or (too often) poorly....you HAVE TOO eliminate as much
friction as possible....or, in the end be very disappointed
and perhaps wondering why your masterpiece doesn't respond as well as others
do.

Ebay has carbide rods/blanks and of course one could probably purchase such
from a variety of other web sellers.
These are simply rounded rods/blanks that some machine shops use to diamond
wheel grind one end into a cutting edge they want.

Use search and enter "carbide rod"; for viewing.   "machprodinc"
specifically has a size that would probably be
VERY convenient to initially use, its 1/8" diameter X 1.5" length, and the
outside diameter surface appears to be quite finely ground...but
there is none anywhere I know of that are ground and diamond POLISHED.  The
auction is for 50 of them and starts at $19.50.
Its a "C4" grade which is 8% cobalt and 92% tungsten carbide.  Theres ALWAYS
something better around of course;
but it very easily beats using any common steel rod/s for its hardness
(avoiding surface indentations), smoother ground surface use
consistency and simply its use longevity.  The seller started with a box of
1000 of them recently and will likely have these auctions
for quite some time to come.

One could obviously likely buy the same or better elsewhere for the exact
number of rods they actually want.

Be aware that sellers falsely claiming their carbide is polished...it likely
isn't...they don't know the difference between
having something ground (a vague silver gray shiny appearance) and something
diamond grit ~ polished (a more mirror like reflection).
Also most carbide isn't even ground, its shape molded....it usually looks
blackish, but can be other colors....you sure don't want
that rough a surface.  Grinding is simply a grit size scratching
action...and finer diamond based grits (polishing) yield a much smoother
and visually they can yield a ~ mirror reflection finish.

If....you want to go further and actually do ~ polishing, I note that Titan
Tool Supply, Inc. has a variety of diamond
grits on small size foil and sheets.
http://www.titantoolsupply.com/catalog.asp?prodid=506100
This diamond grit material will likely cost alot more than the carbide
rod/s.  Theres probably many others around with cheaper
or better material.

Take care, Meredith
Chris is right to emphasize using carbide...or any of the harder and/or smoother surface materials...they are all better for seismo pivot
material than run of the mill steel and iron rods.  The pivot itself is the "heart" of your seismo enertia mass response working

reasonably well or (too often) poorly....you HAVE TOO eliminate as much friction as possible....or, in the end be very disappointed
and perhaps wondering why your masterpiece doesn't respond as well as others do.   


Ebay has carbide rods/blanks and of course one could probably purchase such from a variety of other web sellers.
These are simply rounded rods/blanks that some machine shops use to diamond wheel grind one end into a cutting edge they want. 



Use search and enter "carbide rod"; for viewing.   "machprodinc" specifically has a size that would probably be
VERY convenient to initially use, its 1/8" diameter X 1.5" length, and the outside diameter surface appears to be quite finely ground...but


there is none anywhere I know of that are ground and diamond POLISHED.  The auction is for 50 of them and starts at $19.50.
Its a "C4" grade which is 8% cobalt and 92% tungsten carbide.  Theres ALWAYS something better around of course;


but it very easily beats using any common steel rod/s for its hardness (avoiding surface indentations), smoother ground surface use
consistency and simply its use longevity.  The seller started with a box of 1000 of them recently and will likely have these auctions


for quite some time to come.

One could obviously likely buy the same or better elsewhere for the exact number of rods they actually want.

Be aware that sellers falsely claiming their carbide is polished...it likely isn't...they don't know the difference between

having something ground (a vague silver gray shiny appearance) and something diamond grit ~ polished (a more mirror like reflection).
Also most carbide isn't even ground, its shape molded....it usually looks blackish, but can be other colors....you sure don't want

that rough a surface.  Grinding is simply a grit size scratching action...and finer diamond based grits (polishing) yield a much smoother 
and visually they can yield a ~ mirror reflection finish.

If....you want to go further and actually do ~ polishing, I note that Titan Tool Supply, Inc. has a variety of diamond

grits on small size foil and sheets.  http://www.titantoolsupply.com/catalog.asp?prodid=506100
This diamond grit material will likely cost alot more than the carbide rod/s.  Theres probably many others around with cheaper

or better material.

Take care, Meredith