I have a 7.5 hp 36" Tannewitz vertical band saw that we don't use much
any more. We used it for production wood cutting and it zinged through
5/4 hardwood like butter.

Could I put a VFD on it to cut metal?

On 2012-09-11, Tom Gardner Mars@Tacks wrote:
I have a 7.5 hp 36" Tannewitz vertical band saw that we don't use much
any more. We used it for production wood cutting and it zinged through
5/4 hardwood like butter.

Could I put a VFD on it to cut metal?

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

On 9/10/2012 10:18 PM, Ignoramus881 wrote:
On 2012-09-11, Tom Gardner Mars@Tacks wrote:
I have a 7.5 hp 36" Tannewitz vertical band saw that we don't use much
any more. We used it for production wood cutting and it zinged through
5/4 hardwood like butter.

Could I put a VFD on it to cut metal?

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.

On Mon, 10 Sep 2012 22:06:47 -0400, Tom Gardner Mars@Tacks wrote:

I have a 7.5 hp 36" Tannewitz vertical band saw that we don't use much
any more. We used it for production wood cutting and it zinged through
5/4 hardwood like butter.

Could I put a VFD on it to cut metal?

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

On Mon, 10 Sep 2012 22:06:47 -0400, Tom Gardner Mars@Tacks wrote:

I have a 7.5 hp 36" Tannewitz vertical band saw that we don't use much
any more. We used it for production wood cutting and it zinged through
5/4 hardwood like butter.

Could I put a VFD on it to cut metal?

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

On 9/11/2012 12:57 AM, Gunner wrote:
On Mon, 10 Sep 2012 22:06:47 -0400, Tom Gardner Mars@Tacks wrote:

I have a 7.5 hp 36" Tannewitz vertical band saw that we don't use much
any more. We used it for production wood cutting and it zinged through
5/4 hardwood like butter.

Could I put a VFD on it to cut metal?

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.

On 9/11/2012 5:06, Tom Gardner wrote:
I have a 7.5 hp 36" Tannewitz vertical band saw that we don't use much
any more. We used it for production wood cutting and it zinged through
5/4 hardwood like butter.

Could I put a VFD on it to cut metal?

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.

On 2012-09-11, Kristian Ukkonen wrote:

On 9/11/2012 5:06, Tom Gardner wrote:
I have a 7.5 hp 36" Tannewitz vertical band saw that we don't use much
any more. We used it for production wood cutting and it zinged through
5/4 hardwood like butter.

Could I put a VFD on it to cut metal?

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.

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

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.

On 9/11/2012 23:11, Kristian Ukkonen wrote:

On 9/11/2012 5:06, Tom Gardner wrote:
I have a 7.5 hp 36" Tannewitz vertical band saw that we don't use much
any more. We used it for production wood cutting and it zinged through
5/4 hardwood like butter.

Could I put a VFD on it to cut metal?

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.

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.

Kristian Ukkonen wrote:

On 9/11/2012 23:11, Kristian Ukkonen wrote:

On 9/11/2012 5:06, Tom Gardner wrote:
I have a 7.5 hp 36" Tannewitz vertical band saw that we don't use much
any more. We used it for production wood cutting and it zinged through
5/4 hardwood like butter.

Could I put a VFD on it to cut metal?

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.

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..


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.

"Ignoramus9479" wrote in message
...
On 2012-09-11, Kristian Ukkonen wrote:

On 9/11/2012 5:06, Tom Gardner wrote:
I have a 7.5 hp 36" Tannewitz vertical band saw that we don't use
much
any more. We used it for production wood cutting and it zinged
through
5/4 hardwood like butter.

Could I put a VFD on it to cut metal?

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.

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

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

On 2012-09-11, Tom Gardner Mars@Tacks wrote:
I have a 7.5 hp 36" Tannewitz vertical band saw that we don't use much
any more. We used it for production wood cutting and it zinged through
5/4 hardwood like butter.

Could I put a VFD on it to cut metal?

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.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

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 Mars@tacks wrote:
I have a 7.5 hp 36" Tannewitz vertical band saw that we don't use much
any more. We used it for production wood cutting and it zinged through
5/4 hardwood like butter.

Could I put a VFD on it to cut metal?

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

On Monday, September 10, 2012 7:06:49 PM UTC-7, Tom Gardner wrote:
I have a 7.5 hp 36" Tannewitz vertical band saw [for wood]
Could I put a VFD on it to cut metal?

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.

On Thu, 13 Sep 2012 14:25:30 -0700 (PDT), whit3rd
wrote:

On Monday, September 10, 2012 7:06:49 PM UTC-7, Tom Gardner wrote:
I have a 7.5 hp 36" Tannewitz vertical band saw [for wood]
Could I put a VFD on it to cut metal?

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.

-- Bruce --

On Thu, 13 Sep 2012 14:25:30 -0700 (PDT), whit3rd
wrote:

On Monday, September 10, 2012 7:06:49 PM UTC-7, Tom Gardner wrote:
I have a 7.5 hp 36" Tannewitz vertical band saw [for wood]
Could I put a VFD on it to cut metal?

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.

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

"Bruce L. Bergman (munged human readable)"
wrote in message

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.

-- Bruce --

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.

http://grassrootsmotorsports.com/for...w/50939/page1/

jsw

On 2012-09-14, Bruce L. Bergman (munged human readable) wrote:
On Thu, 13 Sep 2012 14:25:30 -0700 (PDT), whit3rd
wrote:

On Monday, September 10, 2012 7:06:49 PM UTC-7, Tom Gardner wrote:
I have a 7.5 hp 36" Tannewitz vertical band saw [for wood]
Could I put a VFD on it to cut metal?

Yes, but to set a VFD to 1/10 speed (about what the steel-cutting

[ ... ]

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.

That makes sense.

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.

Close enough was one which we had at work. It had a pair of
variable-speed belt pulleys to give a fairly wide range of speeds, and
(after opening the bottom blade guard) a push-pull knob which switched a
gearbox in the back to switch in a second speed range, where the top end
of the low range matches the bottom end of the high range. It lest you
puck pretty much any speed needed for various metals and woods. IIRC,
it would go fast enough to handle friction sawing as well -- but I did
not know about that a the time, so I never tried it.

IIRC, it was a DoAll -- and also had the blade welder in the
column. The only thing that I did not like about it was the blade
guides, which were something like Bakelite instead of ball bearings.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---