Converting a hobby bandsaw (10" Craftsman 3 wheel) to a miniature metal cutting saw.

[RaisedByWolves]

Thanks for the details and photos. I have an older version Craftsman with variable speed that can handle up to 1/4” Aluminum at about 1/4 full speed (I used it to split a 6061 1/8” wall 2-1/2” square tube into two channels for my Mini-Lathe DRO project ]Jan/Feb HSM]). The gear reduction would increase its usability (I use a DeWalt portaband in a Swag Off Road stand for most of my metal sawing, but the deeper throat would be nice.

EDIT: Although I used this bandsaw just yesterday and cleaned it out, I didn't take a close look at the drive setup: the blade wheel has an integrally molded XL60T pulley:

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When I first got the bandsaw I looked into a number of ways to slow it down, and they all cost more than the Dewalt/SWAG setup did, so I just use this for wood, plastic and thin Aluminum. However, I didn't consider buying/printing/machining an XL80T fully to fit over the XL60T, which would drop the speed by about 25%. I'll have to do some hunting to see what I can come up with.


Thanks again for the concept.

I didn't see your pic earlier.

Can I get a pic of the entire saw?

 

[ChazzC]

I didn't see your pic earlier.

Can I get a pic of the entire saw?

 

[RaisedByWolves]

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Thanks, I always wondered what those looked like inside.

I'm guessing you needed to run it at 1/4 speed for the torque?

 

[ChazzC]

Thanks, I always wondered what those looked like inside.

I'm guessing you needed to run it at 1/4 speed for the torque?

Pretty much: blade would jam and kick out the overload. Turn off & on the reset and back off on the speed. For most cuts I use the DeWalt, but the deep throat and unlimited length of cut comes in handy.

 

[Garage Dog]

I just found this video of a guy who 3D printed a larger gear to slip over the existing gear. He also converted to a 1/2 blade. He did some before and after cuts on wood, aluminum and a brass bar. Honestly there wasn't hardly any noticeable difference in the cuts, although he said the metal didn't get as hot as with the small gear. I kind of fast forwarded through the video as he's a bit long winded but I think it was worth checking out.

 

[RaisedByWolves]

I just found this video of a guy who 3D printed a larger gear to slip over the existing gear. He also converted to a 1/2 blade. He did some before and after cuts on wood, aluminum and a brass bar. Honestly there wasn't hardly any noticeable difference in the cuts, although he said the metal didn't get as hot as with the small gear. I kind of fast forwarded through the video as he's a bit long winded but I think it was worth checking out.

Thanks for posting that.

He’s way off on his thought process though.

1/2” Blade is not what you need on that saw and he has about/atleast twice the tooth count he should have for those cuts. I’m using a 1/4” 14t blade , he looks to have an 18t.

I cut some 1/2” aluminum after making a new blade and it worked fine, but a 6t blade would have been much better.

Tooth count, kerf and speed are the three things you need to be concerned with. In soft materials you want 3-4 teeth at a higher speed on the material to prevent tooth loading. In harder materials you want more teeth at a slower speed.


For tool steel or stainless you are going to want the ability to run as slow as possible. Something like 100’ per minute.

 

[Garage Dog]

Kind of what I was thinking too. I did like the 3D printed gear though.

Really interested in seeing how yours performs.

 

[RaisedByWolves]

Kind of what I was thinking too. I did like the 3D printed gear though.

Really interested in seeing how yours performs.

I’m confident I’ll get it to do what I want. I mean, I’m throwing $200+ into a $50 saw, so…..

I’ll probably do the bearing upgrade too as that was one of the nicer things in that video.

I was also thinking of whether I could somehow grind half of one of our 1/2” blades and make it into 1/4” as we have some stellar metal cutting blades at work.

Starrett intends pro and another mfg’s pro cut? are really good blades with hard teeth and a soft back for durability.

 

[ChazzC]

I’m confident I’ll get it to do what I want. I mean, I’m throwing $200+ into a $50 saw, so…..

I’ll probably do the bearing upgrade too as that was one of the nicer things in that video.

I was also thinking of whether I could somehow grind half of one of our 1/2” blades and make it into 1/4” as we have some stellar metal cutting blades at work.

Starrett intends pro and another mfg’s pro cut? are really good blades with hard teeth and a soft back for durability.

I have 56-7/8” x 3/16” 14/18 Starrett Pro blade for my Craftsman when I need it.

 

[RaisedByWolves]

Got the motor and controller in a couple days ago and made some good headway in the interim.

They're nice enough, although I didn't expect neither the motor nor the controller to be as big as they are. The controller box is much larger than it looked on the A-Zon ad and the motor, while only 550W is significantly larger then the Customcrafter motors I have on my lathe and mill. Not a dealbreaker and the motor in this sixe is almost a direct fit to replace the factory motor, so that at least eliminates some work.


Motor, controller and 18T pully W 15mm bore from A-Zon that will work perfectly without modification.






What did need modification was the length of the motor shaft to get the drive pully in line with the driven pully.

In this pic you can see the 1/8" aluminum plate, shaft extension coupler and the locking screw for the extension. The aluminum plate is necessary as in the above pic you can see that the front of the motor is stepped and the plate will allow me to mount it flat without a lot of hassle. Just need to drill two holes for the mounting bolts.









In making parts for something I don't have with me at the time, I just make them "Long enuf" to work and trim them down at home. This is what the arraignment looks like as of now.

The pully is in its proper location and you can see how much of the extension I have extra to work with. Ill have 1/4" of room for the jam screw to engage the extension once everything is said and done. The jam screw is necessary as the rotation of the motor will unscrew the extension without some way of fixing it in place and this seemed simple enough to just cut out of a 12mm-1.75 bolt.






Now if you look closely at the above pic, just to the right of the pully you can see the end of the extension, and a slight gap between it and the motor shaft.





Yeah, about that motor shaft......


The threads on the end of this shaft are crap! They did a half assed job with the threading, either not taking a cleanup pass or not cutting deep enough, then just plowed a 5mm endmill through the threads and called it good.


I was a bit concerned when my extension wouldn't thread on, so I blued up the threads and got out the needle file and began cleaning them up wherever the bluing showed interference. This pic is after the third iteration of bluing and cursing....I mean fitting.







This yielded me little if any headway and I was getting a bit miffed at this, until I remembered the nut supplied with the motor wouldn't thread on either. You can see in the above pic how flat the thread tips are which clued me in to them not being cut deep enough. Through some poking around at work I found a tap that must have been made in the same prefecture as this motor, as it had a really crappy looking thread profile, ran that through the extension and VIOLA! The extension just barely threads on. I'm actually OK with this as the way things are the extension runs true and will only get better once the two shoulders meet.

Except, remember that gap? Yeah, there's no undercut in the thread runout/gutter.

Ill deal with that next and then mount the motor.