# Metal cutting bandsaw.



## elewayne (Jun 1, 2018)

Hi, this is my first post.  I have a question. I own a 10" Delta band saw for wood working. I'd like to use it to cut metal. how could I slow down the blade speed. IT has about a 7" pully for the wheel and I can only clear about another inch before it would hit the table. Is there a way to install another shaft to help with speed reduction?


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## benmychree (Jun 1, 2018)

You would need to have an intermediate shaft with suitable pulleys to reduce the speed; the motor pulley would drive a large pulley on the intermediate shaft, and a small pulley also on the intermediate shaft would drive the pulley on the bandsaw shaft, or you could use a worm gearbox to reduce the speed, a separate motor could drive the worm gear and have step pulleys to vary the speed, or use a frequency drive.  There would need to be some sort of clutch coupling to disengage the gearbox output from the bandsaw shaft to use the high speeds.


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## Mitch Alsup (Jun 1, 2018)

You need at least a 10:1 reduction and maybe as much as a 20:1 speed reduction.
Wood gets cut at 1500-3000 fpm while mild steel gets cut at 150 fpm.


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## benmychree (Jun 1, 2018)

The chart on my 20" Rockwell says 150 FPM for thickness under 1/2", 100 FPM for thickness up to 1", and 80 FPM  for anything over 1".


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## FanMan (Jun 1, 2018)

How I made a jack shaft speed reduction for my bandsaw:
https://www.hobby-machinist.com/threads/old-bandsaw.65642/post-551823


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## P. Waller (Jun 1, 2018)

Do you not understand the math or simply how to go about mechanically controlling the speed?


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## Hawkeye (Jun 1, 2018)

I had a 15:1 gearbox that I added to a 1940s Beaver bandsaw I picked up this winter, along with a couple of triple pulleys. I've got 9 speeds from 28 sfpm to 504 sfpm. I love this saw.


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## kd4gij (Jun 2, 2018)

Some pics of the band saw showing the drive system will help us to help you out.


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## Eddyde (Jun 2, 2018)

Here's a bandsaw conversion I recently completed: https://www.hobby-machinist.com/threads/bandsaw-speed-reducer-build.65462/#post-553488


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## Kernbigo (Jun 2, 2018)

Here is my craftsman 3 wheel 10" that i use for wood and metal. I make my own blades from bulk do-all material . I'am running a treadmill motor on it works great no gear box etc. This is the second 1 i did ,the first was a 14" but took up to much room in my small basement shop.


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## pineyfolks (Jun 2, 2018)

A small lawn tractor transmission might do the trick for you.


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## Kernbigo (Jun 2, 2018)

why does everyone think you need a transmission when a simple treadmill motor works great. I have 1 on my band saw and 1 on my south bend lathe/


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## pineyfolks (Jun 2, 2018)

Kernbigo said:


> why does everyone think you need a transmission when a simple treadmill motor works great. I have 1 on my band saw and 1 on my south bend lathe/


I use lawn tractor transmissions on several pieces of equipment when I first started my shop because my dad repaired them and we always had them setting around. Now days there are treadmills setting around everywhere. Years ago they weren't that common, we basically just walked on our own.


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## Eddyde (Jun 2, 2018)

Kernbigo said:


> why does everyone think you need a transmission when a simple treadmill motor works great. I have 1 on my band saw and 1 on my south bend lathe/


Because that would be too easy


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## rwm (Jun 2, 2018)

Kernbigo said:


> why does everyone think you need a transmission when a simple treadmill motor works great. I have 1 on my band saw and 1 on my south bend lathe/



I am curious about that. How is the torque when you are running at 1/20th of full rpm? 
Robert


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## elewayne (Jun 3, 2018)

P. Waller said:


> Do you not understand the math or simply how to go about mechanically controlling the speed?


I won't be strong on the math either, but I was just looking at the machinacals. Just to be sure I had some idea what to do.. I only want to cut sheet metal on the saw anyway. Not 2" thick bar.


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## P. Waller (Jun 3, 2018)

elewayne said:


> I won't be strong on the math either, but I was just looking at the machinacals. Just to be sure I had some idea what to do.. I only want to cut sheet metal on the saw anyway. Not 2" thick bar.



Thin sheet material will be far more difficult then large bars.


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## rwm (Jun 3, 2018)

For Sheet Metal you need really fine teeth. At least 18 TPI. How thin exactly?
Robert


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## Eddyde (Jun 3, 2018)

elewayne said:


> I won't be strong on the math either, but I was just looking at the machinacals. Just to be sure I had some idea what to do.. I only want to cut sheet metal on the saw anyway. Not 2" thick bar.


No worries, If you decide to do the conversion I and others will be here to help. It will be very helpful to post some photos of your machine.


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## Kernbigo (Jun 3, 2018)

If you want to cut sheet you reverse the blade work like a champ

Sent from my SM-G900V using Tapatalk


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## pineyfolks (Jun 3, 2018)

Here's a handy calculator if you decide to use pulleys for reduction.

http://www3.telus.net/findNchoose/pulley_calculator.html


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## Scruffy (Jun 3, 2018)

Very interesting read. I,m in the very slow process of making a 19 teens hundred horizontal mill into something that is usable.
I,m not restoring this,I want it usable. It was a line shaft machine ,converted to electric very poorly.
Here’s my plan make a mirror image step pulley to give me 4 speed choices. Still way to fast ???? So I,m using a 5 speed motorcycle transmission .
Motor to trans to first set of step pulleys, yep I,m nuts  with to much time.
Mill is a b&s
Thanks Ron in ohio


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## Janderso (Jun 4, 2018)

Kernbigo said:


> If you want to cut sheet you reverse the blade work like a champ
> 
> Sent from my SM-G900V using Tapatalk


Really?


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## kd4gij (Jun 4, 2018)

Kernbigo said:


> If you want to cut sheet you reverse the blade work like a champ
> 
> Sent from my SM-G900V using Tapatalk




 I have done that with a plywood blade backwards on a circular saw.


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## elewayne (Jun 4, 2018)

Janderso said:


> Really?


Sorry, I'm not following that at all. Are you saying run the teeth up through the work.  how would one hold it down, with the blade guide?


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## Hawkeye (Jun 4, 2018)

Still turns in the same direction, but the teeth are pointing up instead of down. Less chance of grabbing on thin stock.


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## Susan_in_SF (Jun 17, 2018)

I have a vintage Craftsman bandsaw that I plan to use to cut metal. I was planning on using a 1.5hp DC treadmill motor and my KB Electronics pwm chassis to have variable speed and torque at low speeds.


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## Eddyde (Jun 17, 2018)

Sounds like a good plan.


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## elewayne (Jun 17, 2018)

where would one ind a tread mill motor?


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## Hawkeye (Jun 17, 2018)

Check your local on-line classified ads for treadmills. Some are offered for free, others $50 or less. Get one with a rotary or slider potentiometer to control speed. The ones where you have to repeatedly tap a button to change speeds will drive you crazy. You can get a good stock of various materials when you take a treadmill apart. I've used the belt for things like way covers and car floor mats.


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## rwm (Jun 18, 2018)

I would think that if you used the smallest drive pulley and the largest driven pulley you accommodate, with a variable speed treadmill motor, you could get away without a jack shaft for gear reduction. Thoughts?
Robert


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## FanMan (Jun 19, 2018)

rwm said:


> I would think that if you used the smallest drive pulley and the largest driven pulley you accommodate, with a variable speed treadmill motor, you could get away without a jack shaft for gear reduction. Thoughts?
> Robert



Do the math, see what the speeds work out to.  You don't want to run the treadmill motor too slow as you won't get much torque and the speed will likely drift up and down a bit.


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