36" bandsaw with VFD?

You will need to add an extra cooling fan to cool the motor, if you constantly run it at lower speed.

It would be better to reduce the power through a mechanical system (belts, pulleys etc) than through VFD.

i

That would be tough, it's direct drive.

Is it direct drive or does it use idlers?

If it can be geared down AND a VFD used on it..yes indeed.

If its direct drive...probably for nothing besides aluminum even with a vfd, unless you put a gear reduction in it.

Gunner

-- "Confronting Liberals with the facts of reality is very much akin to clubbing baby seals. It gets boring after a while, but because Liberals are so stupid it is easy work." Steven M. Barry

Sure someone in your area doesnt have a 36" metal cutter they might want to trade?

Gunner

-- "Confronting Liberals with the facts of reality is very much akin to clubbing baby seals. It gets boring after a while, but because Liberals are so stupid it is easy work." Steven M. Barry

Used machines are too plentiful around here. I did sell my other 36" bandsaw, it was a "Northern", both are great iron! The footprint is small enough to just keep for wood odds and ends. I have an 18" vertical metal saw with a welder, so I don't NEED another.

I think you need about 10% of wood spped for steel.

How about changing a motor with different RPM, for example with

1:10 gear reduction? Would add torque nicely.

It might work with a good flux vector VFD, providing good torque at slow speeds.. Just add a fan to blow air to the motor, as the motor fan won't provide enough air at low speeds. Might not be reasonable because of cost of the VFD, unless you find it used.

Kristian Ukkonen.

His mechanisms may not survive 10x the torque.

I am with Gunner actually, he should sell the wood bandsaw and buy a metal bandsaw.

i

Could also be a motor with more poles to get lower RPM.. With 50Hz they go 3000RPM, 1500, 1000, 750, 600, 300, 375, 320, 250.. With dahlander-coils, you could even have several speeds with same motor, keeping it ok for wood and metal.. Still, the gear head motor would be easier to find used..

I think the added torque is not necessary a problem.. At least, my bandsaw slips at the drive wheels for the saw band.. The wheels keep on turning, but the saw band doesn't move..

Kristian Ukkonen.

In a 7.5 HP 60Hz motor? All I see is two ratios in the websites I've looked at. A custom motor would likely cost more than a new saw.

It may still be OK for aluminum. Blade speed for steel is down around

100 feet/minute and the cutting force is uncomfortably high on the fingers and increases as the blade dulls. Sawing 1/4" steel freehand isn't bad, 1/2" and up is rapidly tiring. jsw

I presume at 7.5 hp it is a three-phase motor? A single phase can't benefit from a VFD -- especially a capacitor start one.

You could slow it way down with a VFD (if you set up something to blow air through the motor to keep it cooled), but you would not get the torque needed to seriously cut metal

If it has variable speed build in (adjustable pulleys for about half the range, and a two-speed gearbox which can be shifted for switching between the high and low speeds), then is is already capable of metal cutting as it is -- just put the right blade on it and set the speed properly.

Note that both the variable speed pulleys and the gearbox increase torque as they decrease speed -- which is what you need here.

A quick search on the brand shows a range of sizes bandsaws, all with fixed blade speeds, and the 36" one shows a 10 HP motor, not 7-1/2 HP, but that could be difference in time of manufacture. It looks as though all of their stuff is made for woodworking only.

I'm not sure whether the speed is sufficient to allow friction cutting of steel. That is done with a toothless blade (or a regular one quickly becomes toothless at those speeds in steel) which melts its way through the workpiece.

Good Luck, DoN.

You might look for a blade with ordinary carbide teeth for cutting aluminum & copper & brass, etc. Fancy carbide teeth for cutting steel. This is possible with a wood cutting 10 in. miter saw. Ordinary carbide blades for cutting wood go through aluminum & brass very quickly. A steel cutting blade cut a 2 inch diameter 1040 bar in 40 sec. The next cut hardened the steel & the blade had to be sharpened - possibly due to cutting too slowly. Aluminum, etc, is quick & easy. Iron, etc is quick & hopeful. If you use a lot 12l14 or 1018 steels, the results are a noticebly more reliable. Whether or not a bandsaw will provide the same results is a question with room for optimism.

Hul

Tom Gardner wrote:

My bandsaw has a pulley for cutting steel. Just pull it out for steel, push back in for wood...got 3 ranges on the pulleys, yet never changed the belts...

charl

Yes, but to set a VFD to 1/10 speed (about what the steel-cutting recommendation is) you'll get similar motor torque and current limits, but lower speed and voltage. That means torque x speed, or equivalently current x voltage, is about 1/10 of the '7.5 hp' rating, and you'd be cutting with effectively three quarters horsepower.

Not bad, actually; you don't WANT to zip through steel like it was hardwood. Handling steel stock that needs a 36" throat is gonna be a team-building experience.

If you can make it fit, you are far better to get a gearmotor that drops into that location with the right shaft diameter and length. Then the motor stays at it's native 3450 or 1725 and you get the right FPM on the bandsaw blade.

It would be lovely if they made one big bandsaw design with a car-style 4-speed transmission, then you just shift it to the right speed range and put on the right band. If it's heavy and rigid enough for steel, wood would be cake.

-->--

Indeed!!!

-- "Confronting Liberals with the facts of reality is very much akin to clubbing baby seals. It gets boring after a while, but because Liberals are so stupid it is easy work." Steven M. Barry

I had two 14" Walker-Turner vertical bandsaws in the model shop at Mitre with that feature, though both were stuck in the wood range and I had no budget for repairs.

jsw