I was wondering what the torque at the blade of a metal cutting bandsaw
would be for a lighter duty machine. Or how powerful a motor do these
machines run, and what type of gear reduction do they use.

Thanks.

On Wed, 28 Jul 2004 12:27:46 -0700, "Terry G"
wrote:

===I was wondering what the torque at the blade of a metal cutting bandsaw
===would be for a lighter duty machine. Or how powerful a motor do these
===machines run, and what type of gear reduction do they use.
===
===Thanks.
===


Dunno, but I built a 3 wheeled 20+ inch vertical bandsaw and utilized
a gear box with a 10:1 reduction in it and a 1.5 hp motor (DC) and it
has more guts than needed. I am sur I culd have gotten away with the
3/4 hp DC motor just as fine. It has yet to be pulled down and I have
cut 4" thick alum as well as 1 1/4" steel plate already without a
problem.
Visit my website: http://www.frugalmachinist.com
Opinions expressed are those of my wife,
I had no input whatsoever.
Remove "nospam" from email addy.

What RPM does your motor run at? With a 10:1 reduction I would guess around
1700rpm or so.

"Roy" wrote in message
...
On Wed, 28 Jul 2004 12:27:46 -0700, "Terry G"
wrote:

===I was wondering what the torque at the blade of a metal cutting
bandsaw
===would be for a lighter duty machine. Or how powerful a motor do
these
===machines run, and what type of gear reduction do they use.
===
===Thanks.
===


Dunno, but I built a 3 wheeled 20+ inch vertical bandsaw and utilized
a gear box with a 10:1 reduction in it and a 1.5 hp motor (DC) and it
has more guts than needed. I am sur I culd have gotten away with the
3/4 hp DC motor just as fine. It has yet to be pulled down and I have
cut 4" thick alum as well as 1 1/4" steel plate already without a
problem.
Visit my website: http://www.frugalmachinist.com
Opinions expressed are those of my wife,
I had no input whatsoever.
Remove "nospam" from email addy.

On Wed, 28 Jul 2004 13:05:31 -0700, "Terry G"
wrote:

===What RPM does your motor run at? With a 10:1 reduction I would guess around
===1700rpm or so.
===
==="Roy" wrote in message
et...
=== On Wed, 28 Jul 2004 12:27:46 -0700, "Terry G"
=== wrote:
===
=== ===I was wondering what the torque at the blade of a metal cutting
===bandsaw
=== ===would be for a lighter duty machine. Or how powerful a motor do
===these
=== ===machines run, and what type of gear reduction do they use.
=== ===
=== ===Thanks.
=== ===
===
===
=== Dunno, but I built a 3 wheeled 20+ inch vertical bandsaw and utilized
=== a gear box with a 10:1 reduction in it and a 1.5 hp motor (DC) and it
=== has more guts than needed. I am sur I culd have gotten away with the
=== 3/4 hp DC motor just as fine. It has yet to be pulled down and I have
=== cut 4" thick alum as well as 1 1/4" steel plate already without a
=== problem.
=== Visit my website: http://www.frugalmachinist.com
=== Opinions expressed are those of my wife,
=== I had no input whatsoever.
=== Remove "nospam" from email addy.
===
My DC motor is controlable, and max's out at 3900 rpm.........so I
have a ful range of speeds from slow to fast for cutting various
materials. A VFD would be a good suitable choice as well.
Visit my website: http://www.frugalmachinist.com
Opinions expressed are those of my wife,
I had no input whatsoever.
Remove "nospam" from email addy.

"Terry G" wrote in message
news:R6TNc.6015$1o.735@fed1read06...
I was wondering what the torque at the blade of a metal cutting bandsaw
would be for a lighter duty machine. Or how powerful a motor do these
machines run, and what type of gear reduction do they use.

Thanks.


You have to look at the design of the saw.
The blade needs to run at a certain speed. This is a product of the wheel
diameter and it's speed. The speed of the wheel gives you your gear ratio.
The torque requirements are determined by the width of the blade (kerf), the
feed speed and the material being cut.
Generally, saws should be designed around the blade. The blade supplier
should be able to give you the minimum bend radius for the wheel as well as
the power requirements in various common materials. If in doubt, oversize
the motor and underspeed/underfeed the blade.
The minimum wheel size can be exceeded for a larger throat. Generally, the
larger the better for the saw wheels as the blade is flexed less.

John

You need about 3/4 HP minimum(more is better) for decent cutting speed. The
blade speed should be between 100 and 150 ft/min for ferrous metals.
These two numbers along with the wheel diameter and the motor speed
determine your total reduction ratio and the torque required.

Belt drive is iffy for the final drive to the blade drive wheel because of
slippage with reasonable size pulleys, say 6" or less. It can be done if
you use a tight belt and keep it tight with an adjustable mount. Bicycle
chain or cog belt drive is better. You need a constant hp drive( belts and
pulleys or gears) which rules out a VFD if you are looking to get max.
performance of the saw and motor at any speed.

Commercial saws such as the Delta or Wilton wood/metal use a combination of
belt and gear drive to get about 8 different speeds. You can get by with
2500 ft/min for wood/plastic/brass/aluminum and 100 ft./min for ferrous
metals.

Randy


"Terry G" wrote in message
news:R6TNc.6015$1o.735@fed1read06...
I was wondering what the torque at the blade of a metal cutting bandsaw
would be for a lighter duty machine. Or how powerful a motor do these
machines run, and what type of gear reduction do they use.

Thanks.

Thanks for all the advice. I am pretty familiar with the ratios I need to
achieve, and the blade speeds, but I was just looking for an average torque
so I can determine the size motor to get.

I am going to be installing a second motor, along with my current 1720 RPM
1HP that I currently use for wood. I have a 10 to 1 reduction at the
slowest speed using 3 pulleys and two belts. I will be installing an ac
gearmotor that will run around 150 to 250 rpm, and use the existing 10 to 1
reduction I have. This will bring my spindle RPM down to around 20, which
will make my blade speed around 80 FPM.

I am a little concerned about belt slippage, but I won't be doing to much
heavy duty cutting, and I am usually not in any rush. I can tighten the
belts up pretty well.

So my last bit of missing information is what power ac gearmotor do I buy.
Since I am going through another 10 : 1 reduction I should be able to
multiply the torque rating of the motor by 10 and get my final torque at
the blade.

Almost all the ac gearmotors I have looked at have a torque rating. I am
looking at a 1/3HP motor that turns 180 RPM with 100 in/lbs of torque. So
after I go through my pulley reduction, I should have about 65 FPM blade
speed with around 1000 in/lbs of torque. Does this sound like it would
work? I am not sure what type of steel, or exactly how thick I will be
cutting, therefore I am not sure what blade I will be buying. But I will be
doing lighter duty stuff, probably no more than 1/2" steel, and very little
of it.

I just want to make sure I buy a motor that will be sufficient enough since
I really have no idea what type of motors, and gear reduction the average
lower cost metal band saws use.

Thanks.




"Randal O'Brian" wrote in message
...
You need about 3/4 HP minimum(more is better) for decent cutting speed.
The
blade speed should be between 100 and 150 ft/min for ferrous metals.
These two numbers along with the wheel diameter and the motor speed
determine your total reduction ratio and the torque required.

Belt drive is iffy for the final drive to the blade drive wheel because of
slippage with reasonable size pulleys, say 6" or less. It can be done if
you use a tight belt and keep it tight with an adjustable mount. Bicycle
chain or cog belt drive is better. You need a constant hp drive( belts
and
pulleys or gears) which rules out a VFD if you are looking to get max.
performance of the saw and motor at any speed.

Commercial saws such as the Delta or Wilton wood/metal use a combination
of
belt and gear drive to get about 8 different speeds. You can get by with
2500 ft/min for wood/plastic/brass/aluminum and 100 ft./min for ferrous
metals.

Randy


"Terry G" wrote in message
news:R6TNc.6015$1o.735@fed1read06...
I was wondering what the torque at the blade of a metal cutting bandsaw
would be for a lighter duty machine. Or how powerful a motor do these
machines run, and what type of gear reduction do they use.

Thanks.

It sounds like you've got the basics there. Power = Torque x speed so you
can calculate one from the other two.
Your easiest option isn't to re-invent the wheel but to look at other
bandsaws that use a similar blade and note their motor power. Exceeding this
by one step is generally a good idea, especially if you're looking at real
budget machines.

John

"Terry G" wrote in message
news:2gkOc.12361$1o.9980@fed1read06...
Thanks for all the advice. I am pretty familiar with the ratios I need to
achieve, and the blade speeds, but I was just looking for an average
torque
so I can determine the size motor to get.

I am going to be installing a second motor, along with my current 1720
RPM
1HP that I currently use for wood. I have a 10 to 1 reduction at the
slowest speed using 3 pulleys and two belts. I will be installing an ac
gearmotor that will run around 150 to 250 rpm, and use the existing 10 to
1
reduction I have. This will bring my spindle RPM down to around 20, which
will make my blade speed around 80 FPM.

I am a little concerned about belt slippage, but I won't be doing to much
heavy duty cutting, and I am usually not in any rush. I can tighten the
belts up pretty well.

So my last bit of missing information is what power ac gearmotor do I buy.
Since I am going through another 10 : 1 reduction I should be able to
multiply the torque rating of the motor by 10 and get my final torque at
the blade.

Almost all the ac gearmotors I have looked at have a torque rating. I am
looking at a 1/3HP motor that turns 180 RPM with 100 in/lbs of torque. So
after I go through my pulley reduction, I should have about 65 FPM blade
speed with around 1000 in/lbs of torque. Does this sound like it would
work? I am not sure what type of steel, or exactly how thick I will be
cutting, therefore I am not sure what blade I will be buying. But I will
be
doing lighter duty stuff, probably no more than 1/2" steel, and very
little
of it.

I just want to make sure I buy a motor that will be sufficient enough
since
I really have no idea what type of motors, and gear reduction the average
lower cost metal band saws use.

Thanks.




"Randal O'Brian" wrote in message
...
You need about 3/4 HP minimum(more is better) for decent cutting speed.
The
blade speed should be between 100 and 150 ft/min for ferrous metals.
These two numbers along with the wheel diameter and the motor speed
determine your total reduction ratio and the torque required.

Belt drive is iffy for the final drive to the blade drive wheel because
of
slippage with reasonable size pulleys, say 6" or less. It can be done
if
you use a tight belt and keep it tight with an adjustable mount.
Bicycle
chain or cog belt drive is better. You need a constant hp drive( belts
and
pulleys or gears) which rules out a VFD if you are looking to get max.
performance of the saw and motor at any speed.

Commercial saws such as the Delta or Wilton wood/metal use a combination
of
belt and gear drive to get about 8 different speeds. You can get by
with
2500 ft/min for wood/plastic/brass/aluminum and 100 ft./min for ferrous
metals.

Randy


"Terry G" wrote in message
news:R6TNc.6015$1o.735@fed1read06...
I was wondering what the torque at the blade of a metal cutting
bandsaw
would be for a lighter duty machine. Or how powerful a motor do these
machines run, and what type of gear reduction do they use.

Thanks.

Buy the biggest gearmotor you can fit into your machine design. My 14"
Delta has a 1HP motor and it is pretty slow cutting 1/2" mild steel with the
14 tpi blade running at 100 ft/min. In general, the required torque varies
with the thickness of the workpiece, workpiece material, blade tpi, feed
pressure, lube or not, wheel dia., etc. Hp determines the cutting speed
once you get the blade fpm correct for the workpiece material and I
recommend you go for at least 3/4 hp as an absolute minimum. 1 hp is about
right for a hand fed saw .

Randy

"Terry G" wrote in message
news:2gkOc.12361$1o.9980@fed1read06...
Thanks for all the advice. I am pretty familiar with the ratios I need to
achieve, and the blade speeds, but I was just looking for an average
torque
so I can determine the size motor to get.

I am going to be installing a second motor, along with my current 1720
RPM
1HP that I currently use for wood. I have a 10 to 1 reduction at the
slowest speed using 3 pulleys and two belts. I will be installing an ac
gearmotor that will run around 150 to 250 rpm, and use the existing 10 to
1
reduction I have. This will bring my spindle RPM down to around 20, which
will make my blade speed around 80 FPM.

I am a little concerned about belt slippage, but I won't be doing to much
heavy duty cutting, and I am usually not in any rush. I can tighten the
belts up pretty well.

So my last bit of missing information is what power ac gearmotor do I buy.
Since I am going through another 10 : 1 reduction I should be able to
multiply the torque rating of the motor by 10 and get my final torque at
the blade.

Almost all the ac gearmotors I have looked at have a torque rating. I am
looking at a 1/3HP motor that turns 180 RPM with 100 in/lbs of torque. So
after I go through my pulley reduction, I should have about 65 FPM blade
speed with around 1000 in/lbs of torque. Does this sound like it would
work? I am not sure what type of steel, or exactly how thick I will be
cutting, therefore I am not sure what blade I will be buying. But I will
be
doing lighter duty stuff, probably no more than 1/2" steel, and very
little
of it.

I just want to make sure I buy a motor that will be sufficient enough
since
I really have no idea what type of motors, and gear reduction the average
lower cost metal band saws use.

Thanks.




"Randal O'Brian" wrote in message
...
You need about 3/4 HP minimum(more is better) for decent cutting speed.
The
blade speed should be between 100 and 150 ft/min for ferrous metals.
These two numbers along with the wheel diameter and the motor speed
determine your total reduction ratio and the torque required.

Belt drive is iffy for the final drive to the blade drive wheel because
of
slippage with reasonable size pulleys, say 6" or less. It can be done
if
you use a tight belt and keep it tight with an adjustable mount.
Bicycle
chain or cog belt drive is better. You need a constant hp drive( belts
and
pulleys or gears) which rules out a VFD if you are looking to get max.
performance of the saw and motor at any speed.

Commercial saws such as the Delta or Wilton wood/metal use a combination
of
belt and gear drive to get about 8 different speeds. You can get by
with
2500 ft/min for wood/plastic/brass/aluminum and 100 ft./min for ferrous
metals.

Randy


"Terry G" wrote in message
news:R6TNc.6015$1o.735@fed1read06...
I was wondering what the torque at the blade of a metal cutting
bandsaw
would be for a lighter duty machine. Or how powerful a motor do these
machines run, and what type of gear reduction do they use.

Thanks.

Thanks for all the advice.

I haven't had much luck finding a 1 hp ac gearmotor. The biggest I found,
and was considering getting was a 1/2 HP gearmotor that turned 151 rpm with
180 in/lbs of torque. With the proper gear reduction, I will be able to get
my blade around 80 FPM. Since I am running a 10:1 pulley reduction at the
output of the gearmotor, that would translate to 1800 in/lbs of torque at
the blade.

I don't know if it makes a difference if I am using a gearmotor, or a
standard motor. I do have a 1HP 1720rpm motor that runs the saw normally,
but could I go down in horsepower since I am now running through a gear box,
and a 10:1 pulley reduction?

What other sources besides ebay, and varies surplus stores would have
something like this at a reasonable price? Maybe I am looking for the wrong
thing?

Thanks

"Randal O'Brian" wrote in message
...
Buy the biggest gearmotor you can fit into your machine design. My 14"
Delta has a 1HP motor and it is pretty slow cutting 1/2" mild steel with
the
14 tpi blade running at 100 ft/min. In general, the required torque
varies
with the thickness of the workpiece, workpiece material, blade tpi, feed
pressure, lube or not, wheel dia., etc. Hp determines the cutting speed
once you get the blade fpm correct for the workpiece material and I
recommend you go for at least 3/4 hp as an absolute minimum. 1 hp is
about
right for a hand fed saw .

Randy

"Terry G" wrote in message
news:2gkOc.12361$1o.9980@fed1read06...
Thanks for all the advice. I am pretty familiar with the ratios I need
to
achieve, and the blade speeds, but I was just looking for an average
torque
so I can determine the size motor to get.

I am going to be installing a second motor, along with my current 1720
RPM
1HP that I currently use for wood. I have a 10 to 1 reduction at the
slowest speed using 3 pulleys and two belts. I will be installing an ac
gearmotor that will run around 150 to 250 rpm, and use the existing 10
to
1
reduction I have. This will bring my spindle RPM down to around 20,
which
will make my blade speed around 80 FPM.

I am a little concerned about belt slippage, but I won't be doing to
much
heavy duty cutting, and I am usually not in any rush. I can tighten the
belts up pretty well.

So my last bit of missing information is what power ac gearmotor do I
buy.
Since I am going through another 10 : 1 reduction I should be able to
multiply the torque rating of the motor by 10 and get my final torque
at
the blade.

Almost all the ac gearmotors I have looked at have a torque rating. I
am
looking at a 1/3HP motor that turns 180 RPM with 100 in/lbs of torque.
So
after I go through my pulley reduction, I should have about 65 FPM blade
speed with around 1000 in/lbs of torque. Does this sound like it would
work? I am not sure what type of steel, or exactly how thick I will be
cutting, therefore I am not sure what blade I will be buying. But I
will
be
doing lighter duty stuff, probably no more than 1/2" steel, and very
little
of it.

I just want to make sure I buy a motor that will be sufficient enough
since
I really have no idea what type of motors, and gear reduction the
average
lower cost metal band saws use.

Thanks.




"Randal O'Brian" wrote in message
...
You need about 3/4 HP minimum(more is better) for decent cutting
speed.
The
blade speed should be between 100 and 150 ft/min for ferrous metals.
These two numbers along with the wheel diameter and the motor speed
determine your total reduction ratio and the torque required.

Belt drive is iffy for the final drive to the blade drive wheel
because
of
slippage with reasonable size pulleys, say 6" or less. It can be
done
if
you use a tight belt and keep it tight with an adjustable mount.
Bicycle
chain or cog belt drive is better. You need a constant hp drive(
belts
and
pulleys or gears) which rules out a VFD if you are looking to get max.
performance of the saw and motor at any speed.

Commercial saws such as the Delta or Wilton wood/metal use a
combination
of
belt and gear drive to get about 8 different speeds. You can get by
with
2500 ft/min for wood/plastic/brass/aluminum and 100 ft./min for
ferrous
metals.

Randy


"Terry G" wrote in message
news:R6TNc.6015$1o.735@fed1read06...
I was wondering what the torque at the blade of a metal cutting
bandsaw
would be for a lighter duty machine. Or how powerful a motor do
these
machines run, and what type of gear reduction do they use.

Thanks.

You can use the 1/2hp gearmotor, the only problem will be a slower cutting
rate than if you used the 1hp motor with additional speed reduction to get
the same blade fpm. It doesn't matter where the speed reduction is located,
built into the motor as with a gearmotor, or added on externally.

You can buy a new 1hp gear motor at industrial drive supply houses or at a
place like Grainger, but it will be expensive. Most hobbyists use the motor
that came with their saw and add on the required speed reduction with belts
and pulleys. It just takes about 3 stages to get 100 fpm at the blade
instead of just one stage when you use a gear motor.

Belts or gears have a pretty high efficiency and you won't lose more than
about 10% of your motor power using either one. It all boils down to what
you can buy, scrounge or dig out of your scrap box. Just remember that the
motor HP determines the cutting rate through your workpiece and the
workpiece material determines the blade speed in fpm.

Randy

"Terry G" wrote in message
news:ngEOc.17453$1o.16246@fed1read06...
Thanks for all the advice.

I haven't had much luck finding a 1 hp ac gearmotor. The biggest I found,
and was considering getting was a 1/2 HP gearmotor that turned 151 rpm
with
180 in/lbs of torque. With the proper gear reduction, I will be able to
get
my blade around 80 FPM. Since I am running a 10:1 pulley reduction at the
output of the gearmotor, that would translate to 1800 in/lbs of torque at
the blade.

I don't know if it makes a difference if I am using a gearmotor, or a
standard motor. I do have a 1HP 1720rpm motor that runs the saw normally,
but could I go down in horsepower since I am now running through a gear
box,
and a 10:1 pulley reduction?

What other sources besides ebay, and varies surplus stores would have
something like this at a reasonable price? Maybe I am looking for the
wrong
thing?

Thanks

"Randal O'Brian" wrote in message
...
Buy the biggest gearmotor you can fit into your machine design. My 14"
Delta has a 1HP motor and it is pretty slow cutting 1/2" mild steel with
the
14 tpi blade running at 100 ft/min. In general, the required torque
varies
with the thickness of the workpiece, workpiece material, blade tpi, feed
pressure, lube or not, wheel dia., etc. Hp determines the cutting speed
once you get the blade fpm correct for the workpiece material and I
recommend you go for at least 3/4 hp as an absolute minimum. 1 hp is
about
right for a hand fed saw .

Randy

"Terry G" wrote in message
news:2gkOc.12361$1o.9980@fed1read06...
Thanks for all the advice. I am pretty familiar with the ratios I
need
to
achieve, and the blade speeds, but I was just looking for an average
torque
so I can determine the size motor to get.

I am going to be installing a second motor, along with my current 1720
RPM
1HP that I currently use for wood. I have a 10 to 1 reduction at the
slowest speed using 3 pulleys and two belts. I will be installing an
ac
gearmotor that will run around 150 to 250 rpm, and use the existing 10
to
1
reduction I have. This will bring my spindle RPM down to around 20,
which
will make my blade speed around 80 FPM.

I am a little concerned about belt slippage, but I won't be doing to
much
heavy duty cutting, and I am usually not in any rush. I can tighten
the
belts up pretty well.

So my last bit of missing information is what power ac gearmotor do I
buy.
Since I am going through another 10 : 1 reduction I should be able to
multiply the torque rating of the motor by 10 and get my final torque
at
the blade.

Almost all the ac gearmotors I have looked at have a torque rating. I
am
looking at a 1/3HP motor that turns 180 RPM with 100 in/lbs of torque.
So
after I go through my pulley reduction, I should have about 65 FPM
blade
speed with around 1000 in/lbs of torque. Does this sound like it
would
work? I am not sure what type of steel, or exactly how thick I will
be
cutting, therefore I am not sure what blade I will be buying. But I
will
be
doing lighter duty stuff, probably no more than 1/2" steel, and very
little
of it.

I just want to make sure I buy a motor that will be sufficient enough
since
I really have no idea what type of motors, and gear reduction the
average
lower cost metal band saws use.

Thanks.




"Randal O'Brian" wrote in message
...
You need about 3/4 HP minimum(more is better) for decent cutting
speed.
The
blade speed should be between 100 and 150 ft/min for ferrous
metals.
These two numbers along with the wheel diameter and the motor speed
determine your total reduction ratio and the torque required.

Belt drive is iffy for the final drive to the blade drive wheel
because
of
slippage with reasonable size pulleys, say 6" or less. It can be
done
if
you use a tight belt and keep it tight with an adjustable mount.
Bicycle
chain or cog belt drive is better. You need a constant hp drive(
belts
and
pulleys or gears) which rules out a VFD if you are looking to get
max.
performance of the saw and motor at any speed.

Commercial saws such as the Delta or Wilton wood/metal use a
combination
of
belt and gear drive to get about 8 different speeds. You can get by
with
2500 ft/min for wood/plastic/brass/aluminum and 100 ft./min for
ferrous
metals.

Randy


"Terry G" wrote in message
news:R6TNc.6015$1o.735@fed1read06...
I was wondering what the torque at the blade of a metal cutting
bandsaw
would be for a lighter duty machine. Or how powerful a motor do
these
machines run, and what type of gear reduction do they use.

Thanks.

Thanks for the advice.

I ended up picking up a 1/2 HP 150rpm 180 in/lbs of torque motor for $45.00.
The price was right, so I will give it a try. My plan is to install both
motors (one for wood, one for metal) side by side in my saw. I will use the
existing 4 position pulley on my motor and install it on another shaft which
will sit between the two motors. Then I can connect one motor or the other
by just switching the belt over. This will let me keep my adjustability of
the wood cutting, and even give me a bit of flexibility with my metal
cutting. We'll see if it works or not.

Terry

"Randal O'Brian" wrote in message
...
You can use the 1/2hp gearmotor, the only problem will be a slower cutting
rate than if you used the 1hp motor with additional speed reduction to get
the same blade fpm. It doesn't matter where the speed reduction is
located,
built into the motor as with a gearmotor, or added on externally.

You can buy a new 1hp gear motor at industrial drive supply houses or at a
place like Grainger, but it will be expensive. Most hobbyists use the
motor
that came with their saw and add on the required speed reduction with
belts
and pulleys. It just takes about 3 stages to get 100 fpm at the blade
instead of just one stage when you use a gear motor.

Belts or gears have a pretty high efficiency and you won't lose more than
about 10% of your motor power using either one. It all boils down to what
you can buy, scrounge or dig out of your scrap box. Just remember that
the
motor HP determines the cutting rate through your workpiece and the
workpiece material determines the blade speed in fpm.

Randy

"Terry G" wrote in message
news:ngEOc.17453$1o.16246@fed1read06...
Thanks for all the advice.

I haven't had much luck finding a 1 hp ac gearmotor. The biggest I
found,
and was considering getting was a 1/2 HP gearmotor that turned 151 rpm
with
180 in/lbs of torque. With the proper gear reduction, I will be able to
get
my blade around 80 FPM. Since I am running a 10:1 pulley reduction at
the
output of the gearmotor, that would translate to 1800 in/lbs of torque
at
the blade.

I don't know if it makes a difference if I am using a gearmotor, or a
standard motor. I do have a 1HP 1720rpm motor that runs the saw
normally,
but could I go down in horsepower since I am now running through a gear
box,
and a 10:1 pulley reduction?

What other sources besides ebay, and varies surplus stores would have
something like this at a reasonable price? Maybe I am looking for the
wrong
thing?

Thanks

"Randal O'Brian" wrote in message
...
Buy the biggest gearmotor you can fit into your machine design. My
14"
Delta has a 1HP motor and it is pretty slow cutting 1/2" mild steel
with
the
14 tpi blade running at 100 ft/min. In general, the required torque
varies
with the thickness of the workpiece, workpiece material, blade tpi,
feed
pressure, lube or not, wheel dia., etc. Hp determines the cutting
speed
once you get the blade fpm correct for the workpiece material and I
recommend you go for at least 3/4 hp as an absolute minimum. 1 hp is
about
right for a hand fed saw .

Randy

"Terry G" wrote in message
news:2gkOc.12361$1o.9980@fed1read06...
Thanks for all the advice. I am pretty familiar with the ratios I
need
to
achieve, and the blade speeds, but I was just looking for an average
torque
so I can determine the size motor to get.

I am going to be installing a second motor, along with my current
1720
RPM
1HP that I currently use for wood. I have a 10 to 1 reduction at
the
slowest speed using 3 pulleys and two belts. I will be installing
an
ac
gearmotor that will run around 150 to 250 rpm, and use the existing
10
to
1
reduction I have. This will bring my spindle RPM down to around 20,
which
will make my blade speed around 80 FPM.

I am a little concerned about belt slippage, but I won't be doing to
much
heavy duty cutting, and I am usually not in any rush. I can tighten
the
belts up pretty well.

So my last bit of missing information is what power ac gearmotor do
I
buy.
Since I am going through another 10 : 1 reduction I should be able
to
multiply the torque rating of the motor by 10 and get my final
torque
at
the blade.

Almost all the ac gearmotors I have looked at have a torque rating.
I
am
looking at a 1/3HP motor that turns 180 RPM with 100 in/lbs of
torque.
So
after I go through my pulley reduction, I should have about 65 FPM
blade
speed with around 1000 in/lbs of torque. Does this sound like it
would
work? I am not sure what type of steel, or exactly how thick I will
be
cutting, therefore I am not sure what blade I will be buying. But I
will
be
doing lighter duty stuff, probably no more than 1/2" steel, and very
little
of it.

I just want to make sure I buy a motor that will be sufficient
enough
since
I really have no idea what type of motors, and gear reduction the
average
lower cost metal band saws use.

Thanks.




"Randal O'Brian" wrote in message
...
You need about 3/4 HP minimum(more is better) for decent cutting
speed.
The
blade speed should be between 100 and 150 ft/min for ferrous
metals.
These two numbers along with the wheel diameter and the motor
speed
determine your total reduction ratio and the torque required.

Belt drive is iffy for the final drive to the blade drive wheel
because
of
slippage with reasonable size pulleys, say 6" or less. It can be
done
if
you use a tight belt and keep it tight with an adjustable mount.
Bicycle
chain or cog belt drive is better. You need a constant hp drive(
belts
and
pulleys or gears) which rules out a VFD if you are looking to get
max.
performance of the saw and motor at any speed.

Commercial saws such as the Delta or Wilton wood/metal use a
combination
of
belt and gear drive to get about 8 different speeds. You can get
by
with
2500 ft/min for wood/plastic/brass/aluminum and 100 ft./min for
ferrous
metals.

Randy


"Terry G" wrote in message
news:R6TNc.6015$1o.735@fed1read06...
I was wondering what the torque at the blade of a metal cutting
bandsaw
would be for a lighter duty machine. Or how powerful a motor do
these
machines run, and what type of gear reduction do they use.

Thanks.