Bandsaw and Gear Reducer?

[JHCC]

So, while I'm waiting for a chance to go pick up the reducer, a thought occurs to me. The model I'm getting has a mounting plate to attach a 56C frame motor, and I just happen to have a 56C frame Marathon motor powering my horizontal bandsaw, attached to a mount I bodged together back in the summer of 2019.

I'm thinking that I can take the Baldor off the vertical bandsaw, make a new mount for it on the horizontal bandsaw, and reverse its direction, thus eliminating the annoying twist I had to put in the drive belt because the Marathon is not reversible:

The Marathon would then be available to mount on the gear reducer once that arrives in the shop.

My only concern is whether or not the 1/2 hp Baldor would be strong enough to power the horizontal bandsaw. I had trouble with a 1/3 hp motor wimping out on me when I first set it up, but I think that was a peak horsepower rating, not continuous. I suppose I can temporarily set up the Baldor on the horizontal saw and see how it behaves before I make any permanent decisions. 

[JHCC]

Well, I put the Baldor on the horizontal saw and cut through a piece of 1/2” x 1-3/4” flat bar with no trouble at all, so long as I didn’t have the feed cylinder adjusted too fast. I think we’re good to go. 

[Frosty]

On 12/14/2020 at 5:39 AM, JHCC said:

Maybe a manual gearbox with four forward speeds and reverse?

11 hours ago, JHCC said:

Would that be to add mass or to add rigidity

Rigidity. You can screw the saw to the bench or reinforce the stand to hold it down so mass isn't that important.  Rigidity is a big deal. 

There also isn't any ribbing structure around the blade wheel bearings, it isn't as important there as it is in the neck and spine but flex isn't good. 

Frosty The Lucky.

[JHCC]

There are ribs radiating out from the bottom wheel bearing, so there’s some stiffness there. 

There’s also some ribbing running to the bracket that holds the tension/tracking mechanism:

 

And there’s also a bit of ribbing on the inside of the front cover. 

The front cover fits quite snugly onto the back, with a close-fitting lip all the way around. I suspect that when the four knobs are tightened down, the whole thing is pretty rigid. Still, it’s good to know that I can always add some concrete or Bondo later if necessary. 

[JHCC]

(It is missing two knobs, though, so I'll have to make replacements.)

[JHCC]

Picked up the “used” gear reducer, and it turned out to be brand spanking new. Very happy. 

[ThomasPowers]

Hooking it to your bicycle?

[JHCC]

The bike gears down pretty low already, thanks!

 I mounted the reducer to the motor, which went very well. 

The only issue is that it turns counterclockwise, and the motor is not reversible. That means I can’t do a direct drive as discussed above, but it shouldn’t be a problem to get things turning the right way with belts and pulleys. That’ll be my next step, once I pick up a 5” pulley with a 1” bore. 

[Frosty]

Can you turn it over and face the output shaft the other direction? That'd reverse rotation to the saw.

Frosty The Lucky.

[JHCC]

You mean open it up, take it apart, and reassemble it with the output shaft sticking out of the other side? 

[Frosty]

 No. I mean unbolt it from the motor, rotate it on the motor shaft till the shaft is facing the other way and bolt it back on the motor. You'll need to shift the whole unit a little ways, 6-8" +/- so the drive pully will align with the saw pully. 

Unless it leaks oil "upside down" the worm being in the oil bath will lube the unit just fine. 

The shaft will still be turning counter clockwise when facing the shaft end, that doesn't change. What it will change is the direction it'll turn the belt and as far as the saw is concerned that's all that matters.

If worse comes to worse you could point the motor and drive the other direction but that changes the stand's shape considerably. Something I'd really try to avoid.

Frosty The Lucky.

[JHCC]

Oh, I see what you're saying. No, there's no problem with the shaft turning CCW if I'm using belts and pulleys: seen from the back, both the motor and the drive pulley turn CCW, pulling the blade down into the work.

I was thinking about doing a direct drive, where the output shaft of the reducer would connect directly to the drive shaft of the saw with a lovejoy connector. In that case, the reducer shaft needs to be turning CW, to turn the saw shaft CCW.

Ironically, this wouldn't be a problem if I hadn't switched motors between the bandsaws. However, the new setup on the horizontal bandsaw with the switched outlet and the automatic shutoff switch works so well that I don't have any inclination to move things back.

 

[Frosty]

Ah HAH! I was thinking  of the other saw. . . Nevermind. 

Frosty The Lucky.

[JHCC]

My other saw, or your other saw?

 

 I’m confused....  

[JHCC]

I’ve built a hinged bracket for mounting the motor and got that all set up. The on/off switch is on the far side of the grey box on the left, so it's in a very convenient and ergonomic spot.

I’ve got the drive pulley on order from Amazon and blades on the way from sawblade.com. I need to get replacement thrust bearings and blade guides, the latter of which are discussed elsewhere. 

(By the way, you can see a butt weld right in the middle of the bracket; that's from my correction for having made the bracket seven inches too long!)

[JHCC]

Interesting development: I was looking for information online about the guide blocks and ran across a garagejournal post someone doing an almost identical wood-to-metal conversion of this very model of saw, also using a gear reducer. The interesting thing is, they mounted TWO motors underneath the saw: one with the reducer, and one without. This enables them to switch back and forth between wood and metal just by moving the drive belt. (They don't switch blades, which strikes me as less than ideal at best.) I will definitely see if I can swing this with my saw, as I might have a suitable extra motor knocking around the place.

I'm not going to directly link to the other forum, but the post is at https://www.garagejournal[DOT]com/forum/showpost.php?p=5694351&postcount=61

[JHCC]

I dug out an old Craftsman motor that a neighbor gave me, to see if that would work. Unfortunately, it's a 3450 rpm, which would give me a much too fast sfm for cutting wood, and the only way to bring the speed down would be to use an impossibly small drive pulley. Time to dig around some more in the old motor supply.

On the bright side, the new tires arrived, so I'll be putting those on soon. 

[JHCC]

Dug out the original motor from The Pressciousss, which I think will work. It’s a 1-1/2 hp Baldor, running at 1725 rpm off 110v single-phase. Perhaps a bit overpowered, but otherwise just the thing. I’ll need to get a 2” drive pulley to fit its 7/8” shaft and the materials to wire it up, and we’ll be good to go. 

In other news, the new tires and blades have arrived and the pulley for the reducer has shipped, so I should have it set up for metal cutting up soon and for wood cutting shortly thereafter. 

[JHCC]

Actually, now that I think of it, I did simply move the original plug, cord, and switch from The Pressciousss over to the air curtain on my gas forge. Nothing that says I can’t move them back to this motor again. 

Also, I forgot to mention that this motor is reversible, so while I’m figuring out how to mount it, I don’t need to worry about which way it turns. 

[Frosty]

Ahhh, my not helping seems to have had beneficial effects. You had everything you needed and only needed to do some tinkering. 

I no longer know which saw I meant. Not mine, it's been working perfectly for 25 years or so I ain't a messing with it.

Frosty The Lucky.

[JHCC]

Not everything I needed: I’ve still had to order thrust bearings, drive pulleys, and blades. (Side note: sawblade.com came through with their usual commendable promptness.) I’ll be making the missing guide blocks myself; I think I’ve got some 1/4” brass rod around here somewhere, but I do have steel I can use of the brass doesn’t come to light quickly. 

[Frosty]

I get mine from sawblade . com too. I get 6 packs for about $3 more than individual blades locally.

Do you have brazing rod and a torch? braze a layer on one side of the steel blocks and sand it smooth for your guide blocks. You can forge braze the bearing surface easily enough but a torch is quicker.

Frosty The Lucky.

[JHCC]

I’m honestly not sure if it’s worth the trouble, especially given how small the actual contact area is. We’ll see how it goes. 

One thing I wanted to ask you: given that the original manual from Craftsman recommends a 1/3 hp motor with a 5:2 reduction, I’m wondering what practical effect (in any) having so much more torque from a 1 hp on a 25:1 reduction will have for cutting metal or a 1-1/2 hp on 2:1 for wood?

[Frosty]

You want the blade speed much lower cutting metal than wood. I don't know FPM but I've used both and a metal band saw tends to go slow enough to see the teeth. 

Frosty The Lucky.

[JHCC]

I’m not worried about blade speed; that’s already sorted. I’m just curious about what the practical effect might be to having 4-5 times as much horsepower powering the blade, even at the same speed.