Ned Simmons wrote:

On Thu, 19 Jun 2008 12:27:39 -0700 (PDT), N4aeq
wrote:


As a electronic guy I often need to cut 1/16-3/16" & sometimes 1/2
small pieces of Aluminum, I
have a Craftsman cast iorn 12" bandsaw. They sell metal cutting
blades for these all the time
however I know I will have to drop the rpm. One blade has 9 tpi the
other 14 tpi but neither say
what rpm to run. The stock saw has 1725rpm motor 2/1 pully for 862
rpm of the 12" wheel.
If i figure it right thats around 2700 fpm, again this is for wood
cutting. What would be a good
fpm to go for when cutting aluminum.


Oh, about 2700fpm would be good.g The chart on my DoAll says
1500fpm, but only because that's the saw's highest speed. Machinery's
Handboook says 1000 to 3000fpm. I used to cut aluminum at around
5500fpm on a 36" saw I owned, but softer alloys are more prone to
gumming the blade at that speed. A bar of stick wax, made for metal
cutting, will help prevent that.

A 6 TPI hook tooth, same as for wood, is a good all-around blade for
aluminum, a somewhat finer blade might be better at the low end of
your thickness range. The usual 3 teeth in the work rule for cutting
metals at low speed does not apply to soft materials at high speed;
you'd have to be feeding your material at 16 inches per second to take
a .003 chip per tooth with the above setup. If you don't already have
something close, most small cities will have a saw shop that will make
up any blade you want.



Another way to cut the thin stuff is to sandwich it btween a couple of
pieces of scrap laywood. This gives it support and holds it in place.

Jim