I've purchased a blade made by Matsu****a
http://www.matsu****aamerica.com/steelstud.htm and it is meant to be used
in a 7 1/4" handheld circular saw which has a no-load rated speed of 5300
RPM . I've cut 1 1/4" thick mild steel plate with it and did not have any
problems. How blade life, etc. is working this hard will be interesting to
see. I honestly don't know if it needs to run slower, the chip that is
formed is small, 1 1/4 curl, and blue.
I do agree that 12" dia. might be too big to run at 3800 rpm.
(SFM=12x3.14x3800/12=11932 ) That's a significant amount faster than the
10000 sfm that my 7.25" runs.

There are other manufacturers that make them, just do a search for "steel
cutting saw blades" and you'll find info which seems to corraborate some of
the comments that others have made.



"John Allen" wrote in message
news
I can't seem to find an old post that talked about a carbide tipped saw
for
cutting steel that can be used in a normal abrasive cuttoff saw.
Can anyone please point me to the site where they have these. None of the
local manufacturers make anything bigger then 230mm and I need 300mm plus
for cutting larger HRS.
Tks in advance
John Allen
New Zealand.