Bandsaw motor conversion WIP

[gixxer]

Have a woodworking bandsaw that's too fast for steel? Wanna slow it down the right way? HERE'S HOW.

14" bandsaw $200
Motor and redux $54 shipped (thanks greedbay)
4 prong plug $15
4 prong outlet $6
7ft 10/4 600v electrical wire $16
pulley for 1" output shaft FREE (canned from old saw parts, cut down on lathe)

I got an import bandsaw end of last year with the intention of converting it to cut steel. I already have two VFD's for my other equipment, so the plan is to add a 4 prong 220v outlet to the side of my VFD box and put 4 prong plugs on the machines.

After measuring I can fit the new motor vertical, which works cause the tension adjusting mount slots are vertical too. All I have to do is make adapter plates cause I am sure the redux mount holes will not line up with the slots. Two sticks of 3/4" G11 (thanks Jatmat) and 4 holes is all it takes.

Remove old motor, remove pulley, chuck it up and start cutting on the lathe. I cut it so all that is left is the 2.5" pulley. Gonna bore it out to 1.000, drill the setscrew hole to 1/4", make new setscrew.

More pics later as I take em. Boy am I excited!!!!!
old motor setup

New motor and redux

 

[gixxer]

Here is a link to a bandsaw SFPM calculator that I used to figure out my speeds.
http://www.owwm.com/math/sfpm.aspx

1750RPM motor, 138RPM output, 2.5" pulley, 6" wheel pulley, 14" band wheel = 211SFPM.

Of course I can spend a couple bucks for a 7" pulley to slow my top speed down even more, but I still have variable speed. I can adjust after some testing.

 

[gixxer]

Okay, let's really get started here. first thing first, made a pulley. Canned the step pulley that was mounted to the old motor. Bore is smaller than what I need, more on that later.
not the same one, but you get the point.
Before...

After. This took maybe an hour or so of shaving and cutting.

NO KEYSEAT!!! Oh bother. WELL, LET'S CUT ONE ON THE LATHE!!! I found this method on the internet last night. Used a 1/4" square lathe bit shimmed up to the random centerline of the bore. Got a few scrapes in to get my lines, then off to the bench vise with files, every now and again going back to the lathe to clean up my work. This took about an hour, a little bit labor intensive, but things went smoothly.
Here's a shot mid scrape.

and the final product.

 

[gixxer]

Okay, time for adapter plates. The slots on the saw will not line up with the mounts on the motor, need to make adapter plates! Plenty of 3/4 G11 layin around. The bolts holding the plates to the motor need to be countersunk cause they would not clear the plate on the saw with the slots. I took the time to look at all of this before I drilled, makes things go much smoother. Know the saying measure twice? Well I measured 4 times. Notice one plate has different spacing between the two sets of holes? That's to account for the slots not going all the way down. Drilled for 5/16 bolts, countersunk with the 9/16 bit and tapped in with the hammer.

Plates drilled...

Countersunk bolts

 

[gixxer]

LIKE A GLOVE!!!!!!!


the fit is close, but hey, it still fits!!! The bolts are not tightened down, that's tomorrow when I get a belt. Then I will square everything up, but hey it's in there! Depending on the size of the belt I can get I might have to make 1.5" spacers for the slot mount on the saw to drop the motor 1.5 so I have some adjustment. We will see.

 

[Mark Behnke]

Glad you're doing this, I have a jet 14" saw says wood/metal put it on slow speed, got a Di-master 2 blade and burned it up. I miss calculated the sfpm at 300 something, and Lenox said their blades can run twice as fast as others, i thought it would be good.

The way yours is shown with the pulleys it's around 1200sfpm, I think.
Anyway the dumbest thing I did was pass up a motor like yours at a garage sale a couple of weeks ago. Stood there looking at it thinking I could use it, but Stupid didn't get it.

Thanks for posting this, may still be hope for me.

I calculated changing to 10" pulleys as a way to go, maybe.

 

[gixxer]

The bottom pulley is spinning at 138 RPM, so it should be 211 SFPM. Can you show me how you are calculating it to get 1200?

When they say that the blades can operate at twice the speed of other blades, that is with coolant. Anything will burn up at high speed with no lubricant. I too have a diemaster 2 blade that I roasted cause the saw was too fast.

 

[Mark Behnke]

I was using an online calculator and did it over and over but not confident of my calcs. I'll look for the link and post later.

I'm refering to your first pic "old motor setup"
I found the link
http://www.csgnetwork.com/pulleybeltcalc.html

 

[gixxer]

one way of doing it the long way is RPM x Diameter x .26179939. A little more math before that, 2.5" pulley @ 138 RPM spins a 6" pulley @ 57.50 RPM, so the 14" band wheel is spinning at 57.50.

57.50 x 14 x .26179939 = 210.74 (and a bunch of other numbers past the decimal point...):thumbup:

The other way is calculating the circumference, dividing that by 12, and multiplying that by RPM. I think thats how it goes, I have the formula saved on my other computer.

 

[gixxer]

I was using an online calculator and did it over and over but not confident of my calcs. I'll look for the link and post later.

I'm refering to your first pic "old motor setup"
I found the link
http://www.csgnetwork.com/pulleybeltcalc.html

Oh, the old motor setup. I get it, my bad!

 

[gixxer]

Alrighty then. After a couple trips back and forth to the auto parts store, I got the right length belt. 47" will do it!

After looking at the setup, I went ahead and made 3/4" spacers to drop the whole motor mount so I have room for belt stretch.

3 pcs 3/4 G11, 6 holes, done.

Here's the top spacer installed directly under the blade unit.

 

[gixxer]

AND WE ARE DONE!!!

Everything tightened up, checked, and re checked. Man, 200SFPM is real slow! Although I spent nearly a week of mornings working on this, I feel the finished product is on par with most of my homemade creations. So, I am pretty happy. Saved a bunch of money, did not lose any blood, no burns, the project went smooth. Now that the saw is done, I need to finish installing the 4 prong outlet on the side of the VFD box. Thanks for following along.

 

[balibalistic]

Man, i'm going to do that!! i have a gear reducer that fits 56 frame that will turn 1750rpm to 125rpm. my only think is the odd sized blades. cool creation!!

 

[gixxer]

Odd sized blades? I get my diemaster 2's from bandsawbladesdirect. I dunno if the price is right but they can do any size up to 15 feet in 1/4" increments. I am 93 1/2 and not 92 1/2.