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VFD and bandsaw success

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

Reply to
Eric R Snow
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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

Reply to
Grant Erwin

Greetings Grant, I knew that the small pulley was marginal and I know about Machinery's Handbook power transmission data but it doesn't hurt to try. The cost was about 100 bucks for the VFD and 5 bucks for the motor. I got a screaming deal on some 14/2 with ground SO cord from Home Depot so I can't say what a cord would cost from someone else. The plug and receptacle cost close to 20 bucks for the pair because I use twistlocks for all my machines. If the cost was $200.00 it would still be worth it though just because it makes the saw so much more versatile. Changing the speed to EXACTLY what works best saves tons of time. Just turning the knob is so easy and fast. ERS

Reply to
Eric R Snow

Boy, I know that feeling! It's so satisfying, isn't it? For me, it's the drill press, but the idea is the same - turn the knob until you get the speed you like.

Bob

Reply to
Bob Engelhardt

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