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Grant Erwin Grant Erwin is offline
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Default VFD and bandsaw success

Eric R Snow wrote:

I have Jet brand 14 inch vertical bandsaw that's a knockoff of a Delta
saw. The saw label says it's a wood/metal cutting saw. But even with
the extra pulley set on a jackshaft the lowest speed was still way too
fast to cut steel. The solution I picked is a 1 hp 3 phase 1725 rpm
motor and a VFD. The VFD is connected to 220 volt single phase. With
the belt and pulley combination set up for the lowest RPM and the VFD
set for 120 Hz max the saw will go fast enough for wood cutting and
slow enough for steel cutting. Since the belts are set up for the
lowest speed the smallest diameter pulleys are being used so the
friction between the belt and the small pulleys is not quite enough to
prevent slipping when I put too much pressure on the blade when sawing
steel. I'll try a segmented belt and if that doesn't work then I'm
going to use a toothed belt. But since it only slips once in a while
the priority for this fix is low. Other than that the VFD controlling
the saw speed works very well and because of that the big horizontal
band saw is now slated for the same conversion. No more changing
belts!
ERS


Machinery's Handbook has a good section on how much energy can be
transmitted through a belt/pulley system before the belt slips. The easiest
solution to your slip issue is to switch the pulleys to one which uses two
belts. You'd probably lose the ability to change speeds with the belt but then
you weren't going to use those anyway.

Those "wood metal" saws have a lowest cutting speed of about 800 sfm, which is
OK for some soft nonferrous metals like aluminum.

It's good to see something new on a thread which has been recurring in various
ways for nearly 100 years now, first in places like Popular Mechanics, and in
the last 30 years in various metalworking magazines, and in the last 10 years on
this NG.

I'm curious how much your total cost was, Eric?

Grant