converting band saw to cut steel

[westbj2]

Occasionally I used the band saw to cut out a stock blank but decided that it would be of more use to me cutting steel while making parts, springs, etc.
Did a little research and came up with the changes below.  Works great with a 1/4" blade w/16 teeth per inch.   Not sure of the speed now but it is SLOW.
From the Motor:  2" pulley driving a 7" pulley
From the shaft:  2" pulley driving a 10" pulley
Jim Westberg

[brokenflint]

Jim   got any more particulars on this, I'd really like a metal bandsaw but the price is just ouch!!!

 Broke

[westbj2]

Broke,
The motor is 1725 RPM, and the internal wheels that the 93" blade runs on are 14" in diameter.
Hand rotating the pulley off the motor causes the 7" pulley to rotate about 6 1/2 times for each revolution of the 10" pulley behind it.
I put a spec of masking tape on the blade and rotated the 10" wheel one revolution, this resulted in the tape moving 1/2 of a revolution off the 14" driving wheels.....about 45".
Surface feet per/minute is the key and I cant tell you what it is exactly but it appears similar to specifically designed metal saws I have used. 
I used only one pillow block bearing and in hindsight probably should have supported the shaft there with two.  Will see how it holds up.
First use was cutting a 6" piece of 1095 out of .250" thick stock, it cut accurately and with no problem.
Check ebay for good deals on the bearings, get them with cast housings not pot metal.
Jim

[Dale Halterman]

If I did the math right, your blade is moving at about 361 feet per minute. No idea if that is good for metal or not.

Dale H

[westbj2]

Dale,
I hoped someone would be able to do the math resulting in the SFPM...thanks.
361 SFPM  is a bit fast although it works fine.  If I changed the 7" pulley to a 10" how big a change would this result in?   Think about 250 or so would be perfect.
Jim

[Metalshaper]

Jim,

Having the same idea, the need to saw metal, this is what WE came up with!



 I was given the saw, because it was being thrown away??  My Bud Marlow and I were BS-ing about my desire to have it mounted, instead of using it freehand. 15 minutes of searching for the scrap and a bit of his welding and this was the result!! AND  The whole thing is held together by the knob, normally used as the front hand hold. It is so rigid, I can move it all over or take it to Westerbeck's shop.. just by carrying it with one hand under the throat of the saw!

two speeds as well!

Respect Always
Metalshaper/Jonathan

[Dale Halterman]

361 SFPM  is a bit fast although it works fine.  If I changed the 7" pulley to a 10" how big a change would this result in?   Think about 250 or so would be perfect.
Jim
 

Again, if I am doing it right, the result would be about 253 fpm. Right about where you want to be.

Dale H

[KY Shinner]

I would watch out the way you have the pillow block set up.  What your set up is called is a overhung load.  It looks as though you have a sheave on each side of the bearing.  A different tension on the belts would result in one side of the bearing loaded more than the other.  The bearing is a pivot point.  Unless the bearing accepts a lot of misalignment you are severely reducing the life of the bearing. 

Motor 1725RPM/ 3.5 (this is the ratio of the first reduction 7"/2") = 492rpm
492/5.0 (this is the ratio on the second reduction 10"/2")= 98.57rpm

SFM=.2618 X diamter X RPM
SFM=.2618 X 14 X 98.57
SFM= 361

[FG1]

Jim cool set up , I have an extra small 10 " bandsaw that could use this conversion ! Glad I didnt pitch it when I got the bigger 12" .
Where did you get the pulleys?

[westbj2]

Ed.....I see and agree with your observation on the single pillow block.  There needs to be a  pair of them supporting the shaft.  I still want to slow it down more so once I get the speed right, I will change the shaft support.  I think I will go to heavier duty cast housings with regular bearings.  The single one now working is just a bronze bushing in a pot metal housing.
FG1.....The pulleys are from a local hardware store.  Seems that once you go beyond a 10" size, they come in cast iron only and the prices go up substantially.  12 and 14 inch cast iron pulleys are in the $50 range while the 10" and smaller cast alloy pulleys are  in the $10-$15 range.
Jim

[FG1]

Thanks Jim , I'll have to see what I can come up with .

[KY Shinner]

Westbj2....Yes they are more expensive because you are dealing with a conventional belt instead of fractional horsepower.  I am not sure if you know someone in maintenance at a factory, but they might be able to get you a better price through a supplier (Applied Industrial Technologies, Motion Industries).  Your bearing will be more expensive to if you go to a ball bearing pillow block.  If you are using your set up infrequently it will probably last for awhile.

Better Set up
B----S----B---S

Best Set up
B---S----S----B

B=Bearing
S=Sheave

[holzwurm]

Jim,

Having the same idea, the need to saw metal, this is what WE came up with!



 two speeds as well!

Respect Always
Metalshaper/Jonathan.

That saw looks suspeciously like the one I made for the machine shop at Friendship some years ago. I have on just like it and it is perfect for a small shop. The only shortcoming is, you are limited to the width of the available blades and  it will not cut tight curves like a full size saw with a 1/8 - 1/4" wide blade.

Walk into any tool pawn ship and you can pick up one of those saws for under $50

[Metalshaper]

from Holzwurm;
That saw looks suspeciously like the one I made for the machine shop at Friendship some years ago. I have on just like it and it is perfect for a small shop. The only shortcoming is, you are limited to the width of the available blades and  it will not cut tight curves like a full size saw with a 1/8 - 1/4" wide blade.
>>>>>


 Wouldn't know about anything up at Friendship??  My Bud Marlow threw this one together for me, at his shop. Took about 15 minutes and a couple of visits to the  cut-off pile.  Works good and as a matter of fact,  I was just using it about 10 minutes ago!!

You're right!! Those single width blades make turning any kind of small circle a real PAIN!!

Respect Always
Metalshaper/Jonathan