# bandsawing steel stock - what am I doing wrong?



## Jim Mass (Nov 18, 2014)

Hi,

This is my first post here besides my introductory. Over the past year, I've build up my workshop in order to supplement / compliment my business (consulting mechanical engineer). I've added a belt sander, vertical Jet 14" bandsaw, and a Grizzly G0704 mini-mill. I've worked several projects in aluminum, no problem at all, and the mill runs true and accurate after taking the time to calibrate and tram - loving the mill!
So, now on the the issue...
I'm working my first job in steel - some plates to be made in 1020 steel 1/2" thick. I bought some steel stock and also a bimetal bandsaw blade PN 4179A173 from McMaster.com, and was impressed to see the blade was made by Starrett when it arrived. 
I went to cut the stock, put cutting oil on it, etc, and it didn't cut... period. I didn't pressure it into the blade, let it just let it take its time, but after about 4 minutes, I had cut into the plate about .030", and am sure the blade is now dull.
Thoughts? this was a 10-14 tooth variable pitch blade for 'hard metal' is stated on their website.

What's going wrong? Any advice is appreciated.

Thanks,
Jim


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## kd4gij (Nov 18, 2014)

If that is the wood cutting band saw then it is running way to fast for the steel plate. A metal cutting bandsaw runs much slower than a wood saw.


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## JimDawson (Nov 18, 2014)

What direction are the teeth pointing?


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## Micke S (Nov 19, 2014)

JimDawson said:


> What direction are the teeth pointing?



Good point!

It could also be that the blade tension is too low so it doesn't move as it should.

Some blade types are not meant to be lubed, this is worth checking to.


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## 12bolts (Nov 19, 2014)

Jim,
1st check the teeth are pointing down.
2nd, check the RPM of the wheels and convert that to Feet/minute. You probably want about 100 FPM for 1/2" steel. If your 14" Jet = 14" wheels? then 27 RPM will get you close to 100 FPM. A lot slower than most hobby bandsaws run.
3rd, Although coarse, a 10-14 TPI blade is still pretty fine for 1/2" steel. If you plan on cutting a lot of that thickness, look for a 4 to 6 TPI blade or maybe 8 TPI tops

Cheers Phil


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## Jim2 (Nov 19, 2014)

I use the Starrett bi-metal blades from McMaster-Carr in my portaband, and they hold up real well.  I don't use cutting oil on with the bandsaw. . . .  Maybe the oil isn't helping you?

Jim


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## Bill C. (Nov 19, 2014)

Jim Mass said:


> Hi,
> 
> This is my first post here besides my introductory. Over the past year, I've build up my workshop in order to supplement / compliment my business (consulting mechanical engineer). I've added a belt sander, vertical Jet 14" bandsaw, and a Grizzly G0704 mini-mill. I've worked several projects in aluminum, no problem at all, and the mill runs true and accurate after taking the time to calibrate and tram - loving the mill!
> So, now on the the issue...
> ...



Try cutting without lubrication.  I used lubrication when cutting aluminum.


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## Fabrickator (Nov 19, 2014)

As was said, its a wood saw and youll have to reduce the speed a lot.  I put a triple reduction on mime (jackshaft) and now it cuts steel great.  I have the formula, pulley sizes, pics, but not right now on tablet.


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## 12bolts (Nov 19, 2014)

A good range for a metal cutting bandsaw would be to aim for 70-300 FPM
Hard steels, or thick stock, low end of range. Softer alloys and brasses, higher end of range. Aluminium can be cut faster than that but it just makes the reduction more difficult to set up.
Basic math will get you there. Dia of wheel (in inches) x Pi divide by 12, gets you feet per revolution.

Cheers Phil


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## george wilson (Nov 19, 2014)

Everything else has been covered. My Hardinge lathe starts up so fast,I once wasn't paying attention,and started it backwards. The metal was spinning so fast,I couldn't tell the rotation direction. Then,I wondered why I couldn't get the tool to cut. Only momentary,but,stuff can happen,even after many years as a machinist!!

Your bandsaw needs to go 75 FPM to cut steel .


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## Andre (Nov 19, 2014)

george wilson said:


> Everything else has been covered. My Hardinge lathe starts up so fast,I once wasn't paying attention,and started it backwards. The metal was spinning so fast,I couldn't tell the rotation direction. Then,I wondered why I couldn't get the tool to cut. Only momentary,but,stuff can happen,even after many years as a machinist!!
> 
> Your bandsaw needs to go 75 FPM to cut steel .



I needed to use a dovetail cutter, and it had a 5/8" shank. My 7 Brown and Sharpe taper mill only holds 1/2" so I used a friends BP. Plopped a half inch endmill in there (had to thin down the stock first) so I got familiar with all the knobs on the head, swapped the speed direction lever to hi and went away. For the life of me I couldn't figure out why it wouldn't cut and the chips were welding to the edge. Dumbo moment, didn't know I had to swap the fwd/rev button when moving out of backgear....

He was watching over my shoulder the whole time.....if he eventually hires me I hope he doesn't remember that moment! 

After that it was fun running a 1 1/4" dovetail cutter 2200 RPM :biggrin: Given it was nearly 3 times the recommended speed for that cutter, it left a great finish and the cutter was still scalpel sharp after.


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## george wilson (Nov 19, 2014)

I was using a collet chuck on the Hardinge,which made it even harder to tell the direction. I had switched the lathe to reverse to run a collet in by holding the rear bakelite piece,and forgot.


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## Jamiethesquid (Nov 20, 2014)

Fabrickator said:


> As was said, its a wood saw and youll have to reduce the speed a lot.  I put a triple reduction on mime (jackshaft) and now it cuts steel great.  I have the formula, pulley sizes, pics, but not right now on tablet.



It would be great to see the info on the triple reduction, I have a Shopsmith Bandsaw that I am planning on making into a  Stand alone metal saw.  I am also palnning on building a power hacksaw that is going to run off my lathe.  Craftsman Atlas 6"


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## xalky (Nov 20, 2014)

The OP never returned back to the thread he started. What's up with that??


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## higgite (Nov 20, 2014)

Jim Mass said:


> I went to cut the stock, put cutting oil on it, etc, and it didn't cut... period. *I didn't pressure it into the blade, let it just let it take its time, but after about 4 minutes, I had cut into the plate about .030"*, and am sure the blade is now dull.
> 
> What's going wrong? Any advice is appreciated.
> 
> ...



I'm still in my infancy as a hobby machinist, so pardon if this is a dumb question. Could the 1020 steel possibly have work hardened due to heat build up from too slow of a feed rate or wrong blade speed? Hence, the lack of cutting action?

Tom


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## Jim Mass (Nov 21, 2014)

12bolts said:


> A good range for a metal cutting bandsaw would be to aim for 70-300 FPM
> Hard steels, or thick stock, low end of range. Softer alloys and brasses, higher end of range. Aluminium can be cut faster than that but it just makes the reduction more difficult to set up.
> Basic math will get you there. Dia of wheel (in inches) x Pi divide by 12, gets you feet per revolution.
> 
> Cheers Phil



Hi Everybody,
Thanks for all the advice. So far, we have...
1) wood bandsaw, too fast?
2) teeth pointing down?
3) tpi too high?
4) lube not a step in the right direction
5) blade tension wrong

So, out of those I can eliminate 2). Blade is put on correctly. Matter of fact, if it was put on any other way, the teeth would be facing the back of the machine, right? Anyway, to be clear, this blade does fine with aluminum - just having trouble with the steel.
I think I can also eliminate 5). Blade is tensioned to the indicator on the Jet tensioning mech, and at least appears to run smooth, straight and stable (no noticable flutter, etc). Or, is there something to be known about differences in tension between metal-cutting blades and wood-cutting blades that isn't taken into account on the Jet tension mechanism?
As for 1), I'm sure this is a wood bandsaw (bought it used at a great price). After reading your posts, I went out and tried to estimate the blade surface speed. Best I can tell (very blurry), the wheel is going at about 4 rev/sec. So, converted, that turns out to be in the neighborhood of 875ft/min. Does that sound about right for a wood bandsaw? Anyway, a far cry from the 70-300 FPM ideal that Phil quoted.
As for 3), that would be another step in the wrong direction?
As for 4), don't know. I could easily try without lube, but have the feeling I may have damaged the blade already. It still seems to cut aluminum OK, although more slowly than before my steel cutting episode.
Fabrikator, you mentioned triple reduction (jackshaft), pully changeout, etc. If you could share that info, I'd be grateful.
Thanks,
Jim


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## JimDawson (Nov 21, 2014)

Jim Mass said:


> So, out of those I can eliminate 2). Blade is put on correctly. Matter of fact, if it was put on any other way, *the teeth would be facing the back of the machine, right*?
> 
> Jim



Nope, counting facing teeth to the back, there are 4 ways the blade could be installed.

Teeth front, point up
Teeth front, pointing down (correct)
Teeth back, pointing up
Teeth back, pointing down

The blade will turn inside out so it is possible to install it with the teeth pointing up.  Sometimes you get a blade out of the box that needs to be turned inside out.

My guess is that the saw just needs to run slower.


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## Frank Ford (Nov 22, 2014)

Jim Mass said:


> As for 1), I'm sure this is a wood bandsaw
> Jim



There's the end to it.  

Wood bandsaw runs on the order of ten times faster than steel cutting speed, so at the first touch, the teeth are dulled, and the cutting experience is over.  Just hit a finishing nail in a piece of wood, and the blade is pretty much toast.  Hit a serious chunk of steel at that speed and there's nothing left of even the best blade's teeth.

Now, if you limit your metal cutting to aluminum, you can use the saw for both wood and metal.  Aluminum cuts readily at wood cutting speed.  When I cut thick aluminum on my wood cutting saw, I like to lubricate the blade with an occasional touch of paraffin - it really keeps the cutting action free and avoids the aluminum welding itself to the blade teeth:


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## Bill Gruby (Nov 22, 2014)

WOW -- If that blade is running at the speed to cut wood you are lucky there is a blade at all. Maybe even some of it in you. Steel cutting is slow.

 "Billy G"


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## Jim Mass (Nov 22, 2014)

OK, thanks to all again. 

Looks like there's agreement on the cause - the high speed. 
Jim, thanks for pointing out the 'inside out' blade = upside-down teeth possibility. In future, I won't take that for granted, maybe prevent another ruined blade.
So, where to go from here? I'm space-limited, would really like to have a one-size-fits-all bandsaw, and I really like this Jet (except for it being wrong for steel - right now).
Maybe a few possible routes:
1) permanent speed reduction? 
  - (like Fabrickator's suggestion) jackshaft type; like he said, probably get a 3:1 reduction going that route), and use existing motor; maybe in the neighborhood of $150-$200 cost if I did one myself (bearings, sprockets, shafts, plates, a bit of chain, new v-belt). Seems like it's still higher than ideal speed by a factor of 2 or more.
  - speed reducer; can get bigger reduction, but may not necessarily be able to use same motor; probably custom new motor mount. Has anyone done this? War stories?
2) Change to a variable speed drive? This thought is very compelling, offering possibility of best of both worlds (unless the devil is in the details).
  - what are pros and cons? has anyone done this for a reasonable cost? (My current motor is 1HP, 110V; I currently only have 110V available)
3) Get rid of this saw, and get a correct one for cutting steel (at maybe 10X or more of my current investment)

Thoughts appreciated.

If this discussion is beating dead horses, would appreciate if you point me to the carcasses.

Thanks again, and hope I can help you at some point.

Jim


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## GA Gyro (Nov 22, 2014)

Jim Mass said:


> OK, thanks to all again.
> 
> Looks like there's agreement on the cause - the high speed.
> Jim, thanks for pointing out the 'inside out' blade = upside-down teeth possibility. In future, I won't take that for granted, maybe prevent another ruined blade.
> ...



There are some threads here about VFD's and lathe or mill motors.... Might want to do some reading.  This would not be the cheapest approach.

Here is a thought:  Is there a way to change the pulleys to get a wider range of speeds... AND
Go to a variable speed motor, or a 3PH motor and a VFD?

Just things to consider.

In the end... a new (or pre-owned) combo (horiz and vert) bandsaw with wider speed range (or variable speed)... might be the better thing to consider.


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## dave2176 (Nov 22, 2014)

Harbor Freight 5x6 metal bandsaw, $249.99. Will they let you use the 20% off coupon as well?
Find a 3 phase 1hp motor with 110v VFD. Find a 1hp DC motor and controller for 110v.
 With either of these I would try to  adjust pulley size as well so you can increase motor rpm some and get into the power range of the motor while running the blade slower.
Dave


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## Jim Mass (Nov 22, 2014)

Thanks Guys,

Dave, I was actually thinking something similar - got the idea from Hoss, the famous bf20 milling machine hacker...

You think this might have some possibility?
http://www.ebay.com/itm/261650838569?_trksid=p2060778.m1438.l2649&ssPageName=STRK:MEBIDX:IT

There are tons of these motors and controllers available both new and used for reasonable cost - looks like some of them have flywheels.

And, what needs to be known about the power range of a motor/controller like this? Are there pertinent torque/speed curves I should consult?

- Jim

P.S. Harbor Freight for big power tools, hmm. I know they come from essentially the same place as the Grizzly stuff, but looks like Grizzly takes the steps to assure they receive and distribute the good stuff.


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## Bill Gruby (Nov 22, 2014)

I rebuilt a HF wood band saw. I used a 60:1 reduction unit to slow it down. It cuts like butter now.

 "Billy G"


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## dave2176 (Nov 22, 2014)

Jim Mass said:


> Thanks Guys,
> 
> Dave, I was actually thinking something similar - got the idea from Hoss, the famous bf20 milling machine hacker...
> 
> ...



That is a good option I think.  I've seen them used on wood lathes and small mills with success.I too have trouble with HF power tools.  I own a Grizzly lathe and mill and they are far, far better than anything I've got from HF. I would go as far as saying my Grizzly are as good as the many Jet tools I own.

Dave


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## GA Gyro (Nov 22, 2014)

dave2176 said:


> That is a good option I think.  I've seen them used on wood lathes and small mills with success.I too have trouble with HF power tools.  I own a Grizzly lathe and mill and they are far, far better than anything I've got from HF. I would go as far as saying my Grizzly are as good as the many Jet tools I own.
> 
> Dave



The guys at the airport hanger have a saying about HF:

If it is a HF product, and has bearings in it... proceed with caution.  :nervous:

Seriously... HF has some good stuff... and they have some junk.  

Probably a good idea to carefully inspect anything before buying it.


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## Jamiethesquid (Dec 8, 2014)

Fabrickator said:


> As was said, its a wood saw and youll have to reduce the speed a lot.  I put a triple reduction on mime (jackshaft) and now it cuts steel great.  I have the formula, pulley sizes, pics, but not right now on tablet.



I would love to see your setup for the triple speed reduction. 


Jamie


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## railfancwb (Dec 12, 2014)

Consider a riding mower transmission. Here is a three speed (probably plus reverse) which appears to have only one output - to a sprocket. 

Look at this on eBay:

http://pages.ebay.com/link/?nav=item.view&alt=web&id=181579905817

Foote 3 Speed Transmission H Pattern Pat #D208,213

There are also four- and five-speed units, and hydrostatic designs which vary from forward to reverse with a single lever. 

Have seen automotive transmissions used to increase speed selections for old lathes. Have seen hydrostatic transmission used in a 7-1/2" gauge locomotive. 

If this approach seems appealing, cultivate someone who repairs mowers for a living - preferably from a well equipped home shop. Might get an advantageous buy on what you need and certainly could learn a lot about hooking things up.


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## Jim Mass (Jan 3, 2015)

Hey Guys,

I'm the OP on this, posting with what I finally did for the solution.

After watching Ebay for a couple weeks, I ended up getting an new old stock Emerson 1HP 90VDC motor and a used Dayton DC variable frequency drive, and replaced the motor.
Cost me $150 (almost exactly), a couple gallons of gas to pick the components up, and about 4 hours to put them in. Things didn't fit perfectly, I had to make transition brackets because the motor length was different from original, etc.
I also remoted the VFD power-on lamp and the speed pot to the front panel right below the on-off switch, while the rest of the VFD enclosure is mounted inside the enclosed under-saw platform.
Had a big scare when I cut my first steel at ~250FPM, and the blade & moter just stopped under the load. Then I discovered that the jumper inside the VFD was set for a 1/8 HP motor. Re-jumpered for 1HP, and it has plenty of torque over the entire speed range. My test piece was 1/2" 1020 steel, no problem.
It really is so nice to just turn a pot and get the ideal speed for the material you're cutting. I'm glad I did it!

Again, thanks for all your help.

BTW, that last idea with the riding mower transmission looked interesting - probably need to have plenty of room to situate it with the motor though.

- Jim


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## Jamiethesquid (Jan 5, 2015)

Pics?


Jamie


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## george wilson (Jan 6, 2015)

250 FPM is still pretty fast. If you EVER cut tool steel,you have to get the speed down to 75 FPM,or you will quickly ruin another blade. In fact,even at a low speed,01 tool steel can suddenly harden just from the heat of cutting. This hardening is only a few thou. deep,but it is quite enough to strip the teeth off your blade. You need to go 75 FPM,and KEEP the tool steel moving. If you hesitate,it may allow heat from friction to build up and surface harden the steel.


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## Fabrickator (Jan 6, 2015)

I mentioned earlier that I slowed down my 14" floor standing wood band saw for efficiently cutting metals.  It's slower than needed for aluminum and softer metals, but great for steel.  I still use it for wood as well, although it's a little slower than needed.  I'm not in a hurry and so I don't care. I used an electronic tachometer to measure the actual wheel speed to be sure the numbers are correct. Of course, the best thing is a variable speed if you can afford it or need it.

Here is the formula and the sizes that I used.  I think it cost me about $150 for the parts from McMaster-Carr.  I don't have room for another saw, and I already have a horizontal 4X6" for cutting thicker stock, so this mod fit my needs.


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## Jamiethesquid (Jan 7, 2015)

I like it alot. 


Jamie


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## Kernbigo (Jan 8, 2015)

run a thread mill motor and you can do steel and wood


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## Jamiethesquid (Jan 8, 2015)

I have a shopsmith bandsaw. And I honestly considered running it off of the chuck on my lathe. Don't think it would be slow enough though. 


Jamie


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## rwm (Jan 8, 2015)

DC motor is a great solution! 
I am confused about the DC motor and the VFD? I thought VFDs were for AC motors of various phases? I though DC motors were controlled by PWM's? Can someone school me on this?
I have the 18" jet that has high and low gears so I can cut wood or metal. I just leave a 10-14 tpi blade on it.
R


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## Kernbigo (Jan 8, 2015)

vfd are for 3 phase ac motors


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## kd4gij (Jan 8, 2015)

I am shure what he got is a dc verable speed controler. Probly something like this. http://www.ebay.com/itm/DAYTON-2M17...564?pt=LH_DefaultDomain_0&hash=item4ae2a21394


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## rwm (Jan 8, 2015)

kd4gij said:


> I am shure what he got is a dc verable speed controler. Probly something like this. http://www.ebay.com/itm/DAYTON-2M17...564?pt=LH_DefaultDomain_0&hash=item4ae2a21394



Cool. Got it.
R


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## dbassing (Jan 14, 2015)

I have been following this thread  and it got me to thinking about working on my Powermatic 14" wood cutting bandsaw (Model 141). I have been looking for a while for a stand alone vertical metal cutting bandsaw and nothing ever seems to become available. I then thought of trying to find a drive system for a Powermatic Model 143, metal cutting bandsaw. Now this idea of using a 90volt DC 1725 RPM motor with SCR speed controller really seems like the smart and economical way be able to lower the blade speed for metal (changing the blade, of course) while still being able to increase to the max for cutting wood.
I did a bit of math to calculate how slow I would need to turn the drive pulley to get the saw blade to be moving at 75 FPM. (This would me the slowest I would expect to have to turn for cutting steel.) I found that the motor would have to be turning at 40 RPM. Here is how I figured this.
Motor speed =X
Drive pulley dia.= 3"
Driven pulley dia.= 6"
Dia. of bandsaw wheels= 14"
Driven wheel speed= Y RPM
Speed of blade = 75 Feet per minute(FPM)
75=Y*circumference of band saw wheels / 12
75=Y* 43.9/12
Y= 20 RPM
20 RPM= X * Drive pulley dia./driven pulley dia.
20 =X * 3"/6"
X= 40 RPM
Now if this correct what I am wondering is would the motor have sufficient torque at this reduced speed to be able to be effective at cutting steel. Assuming correct blade and appropriate feed pressure?
Thanks for all your help,
David


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## Kernbigo (Jan 14, 2015)

This my 3 wheel, i cut metal and wood, with different blade of course dc thread mill motor set up.


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## Fabrickator (Jan 14, 2015)

DC motors have a lot of torque at most any RPM, unlike AC so it should be fine.  You don't want to "overwork" the blade and generate excess heat.  As long as it's cutting well, just let it do it's thing and don't push it too hard.  If the motor stalls, it's probably not the right motor.  Treadmill motors should have more than enough torque to turn the "correct" band saw blade (designed to carry a 300LB'r).


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## John Hasler (Jan 14, 2015)

dbassing said:


> I have been following this thread  and it got me to thinking about working on my Powermatic 14" wood cutting bandsaw (Model 141). I have been looking for a while for a stand alone vertical metal cutting bandsaw and nothing ever seems to become available. I then thought of trying to find a drive system for a Powermatic Model 143, metal cutting bandsaw. Now this idea of using a 90volt DC 1725 RPM motor with SCR speed controller really seems like the smart and economical way be able to lower the blade speed for metal (changing the blade, of course) while still being able to increase to the max for cutting wood.
> I did a bit of math to calculate how slow I would need to turn the drive pulley to get the saw blade to be moving at 75 FPM. (This would me the slowest I would expect to have to turn for cutting steel.) I found that the motor would have to be turning at 40 RPM. Here is how I figured this.
> Motor speed =X
> Drive pulley dia.= 3"
> ...



You may want a seperate cooling fan.

[Edit]   I don't think you want to try to cover the full speed range from 75 FPM to 1000 with  just motor speed control.  I'd add step pulleys to switch between wood and metal.


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## cjtoombs (Jan 14, 2015)

The problem with doing a wood/metal cutting bandsaw is that the speed range is very wide.  As stated, the low speed should be about 75 FPM.  A good wood bandsaw should run in the neighborhood of 3000 FPM.  This gives a 40:1 speed ratio, which is way to wide for a VFD without using an extreme oversize motor.  The While VFDs will run a motor very slowly, they loose horsepower linearly from the design speed of the motor down.  So if you run a motor at half it's speed, it will be making half it's rated horsepower.  You can run the motor to about twice it's rated speed safely, so that means if you want a half horsepower available at the blade, you could use a 2hp motor and run it at 1/4 the rated speed, which would give an 8:1 speed ratio (1/4 the rated speed to twice the rated speed).  This leaves a 5:1 ratio that would need to be taken up, either with change pulleys or a variable speed pulley.  Single stage variable speed pulleys don't have that kind of ratio, so you would need to use a two stage (accomplished with a special variable speed pulley on a moving countershaft or two normal variable pulleys on a moving countershaft).  That's why most of them are either one or the other.  Not to mention that most shops don't do much work that crosses over from wood to metal and vice versa.  I have a bandsaw that I am planning on putting a combined VFD/variable pulley drive on.  The variable pulleys are outrageously expensive if you buy them new, but they can be picked up on ebay for a fairly low price.  I put one on an antique craftsman 3 wheeler (its the same kind pictures above by kernbigo) that I have, and it can be varied from about 100-300 FPM and it works pretty good.


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## Kernbigo (Jan 14, 2015)

That is why i use dc 0-4000 rpm


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## cjtoombs (Jan 14, 2015)

Kernbigo said:


> That is why i use dc 0-4000 rpm



Regardless, unless you have a separately run fan, you will burn the motor up running at long periods at slow speed and high power levels.


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## Kernbigo (Jan 14, 2015)

my thread mill motors have the original fan on them, my lathe and saw


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## dbassing (Jan 16, 2015)

Thanks all for everyones input and advise. I will be doing a bit more research and report back with what I decide to do and the results.
David


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## iron man (Jan 16, 2015)

I slowed mine down this is the thread it really works good. Ray

http://www.hobby-machinist.com/show...ndsaw-coversion-made-easy?p=100184#post100184


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## Jamiethesquid (Jan 18, 2015)

This thread and a couple other projects has led me to believe that I need a non contact laser tachometer. I am also considering putting a treadmill motor on my Craftsman Atlas 101.21400


Jamie


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## mrbreezeet1 (Jan 18, 2015)

Like they said, step pulley's, or why not maybe say a 2" pulley at the motor,  and maybe a 8" pulley at the bandsaw. 
That would allow you to crank up the speed a little at the motor, and maybe get a little more torque. 
Although they do say the torque is good on these at any speed. 
Then some guys say your better off with a little more speed. 
i just got a 1/2 HP for my lathe. So I will see how that goes. 
My experience on these DC motors is limited. 
It is this motor. Although It is really TEFC, not TENV.
http://www.amazon.com/gp/product/B00KA2R7TA/ref=od_aui_detailpages00?ie=UTF8&psc=1



dbassing said:


> I have been following this thread  and it got me to thinking about working on my Powermatic 14" wood cutting bandsaw (Model 141). I have been looking for a while for a stand alone vertical metal cutting bandsaw and nothing ever seems to become available. I then thought of trying to find a drive system for a Powermatic Model 143, metal cutting bandsaw. Now this idea of using a 90volt DC 1725 RPM motor with SCR speed controller really seems like the smart and economical way be able to lower the blade speed for metal (changing the blade, of course) while still being able to increase to the max for cutting wood.
> I did a bit of math to calculate how slow I would need to turn the drive pulley to get the saw blade to be moving at 75 FPM. (This would me the slowest I would expect to have to turn for cutting steel.) I found that the motor would have to be turning at 40 RPM. Here is how I figured this.
> Motor speed =X
> Drive pulley dia.= 3"
> ...


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