[IDEA] Converting a vertical wood band saw to metal cutting

[TomG]

(05-04-2017, 10:06 PM)Pumpjack Wrote: I guess this is a old thread , but i converted my Delta 14 inch with a transmission from a older riding mower. 3 speed gearbox with a reverse. LoL had to still pulley it down some to get it slow enough but now i can cut steel in first gear and go to 3rd gear for wood.

Does the reverse work like an eraser, in case you saw over the line?

Tom

[alanganes]

I know this is an old thread, but figured you guys might appreciate another approach to doing this:

A while back I saw on Craigslist an old 14" Milwaukee-Delta bandsaw, no stand, motor, etc. Went and had a look, and it seemed in really good shape, just in need of a good cleaning. So I handed over 100 bucks for it. This is a nice solid cast iron saw that according to the serial number is of early 1950's vintage.

I mounted the saw on what used to be a stand for an aquarium (picked from someone's trash...) and added some heavy angle iron feet to it for some added ballast to keep it from being too top-heavy and a create somewhat wider stance for stability.

I had right angle motor/gearbox from a prior project. This was a 1HP DC motor with a 10:1 reduction worm drive gearbox. The controller that I use with this is a KB unit (another salvage and repair item) that has the ability to utilize tachometer feedback. I had a small 24Vdc motor scrounged from somewhere else that looked like it would make a fine 7V/1000RPM tach generator so I modified the gearbox to drive the tach generator directly from the motor shaft. This gives it speed feedback to the controller such that if the motor begins to slow under load, the controller will up the power to the motor to compensate. At full speed, this provides ~180 RPM at the gearbox output and can vary the speed over about a 50:1 ratio with little to no torque loss.

I have a 2:1 speed increase from the gearbox to the saw, so this gives me 360 RPM or about 1300 FPM blade speed with the motor at full speed, adequate if not optimal for wood and soft metals. At a turn of the speed control knob, I can get as low as 70FPM blade speed and anything in between, and with the tach feedback, it cuts without stalling or any perceptible bogging or slowing down. It's quite impressive, really.

Using the blade that it happened to come with (which is too fine for this at 18TPI) I easily cut through some 1/4" steel and a bunch of other stuff I had laying around.

After some new urethane tires, new blades, and a good clean and lube, this is one of thee handiest machined I have. I use it all the time. A few photos:

[wawoodman]

Nice job on the saw.

[TomG]

Looks like it will get the job done.

Love the turnbuckle belt tensioner.

Tom

[Mayhem]

Really nice job Alan. The only thing that concerns me is the lack of a cover on the motor junction box. That is the one place that you don't want a small offcut to land in!

[Dr Stan]

Well done.    

I do however 2nd Mayhem's comment regarding covers.  The belt, pulleys, etc.  Even though I'm more than sure you work safely it only takes one Oh S**t! to eliminate 100 Atta Boys.

[alanganes]

Thanks. Those are all fair comments based on what I posted. Those pics were all taken a while back when the project was still in process. Rest assured that the covers over the wheels are on the saw and all of the electrical stuff is buttoned up and dust-proofed. I do electrical/electronics stuff on some pretty critical systems for a living, so I'm actually pretty good about that stuff in my shop at home. I suppose that may explain the approach I took here.

I do have to admit that I still have not fabricated a proper belt guard for it. I do need to do that but as it's on the far side of the saw from where I work, it's easy to put off the project. Dumb, but guilty as charged. :) Good excuse to trot out the TIG welder, I suppose. I mean if a home shop guy can't over-complicate a simple sheet metal cover, who can?

Tom, the turnbuckle belt tensioner was one of those last minute "what do I have handy" things. The motor pivots from the back end, the gearbox end is unsupported except by the belt. I had figured on the weight of of the motor giving enough tension on the belt to keep things moving, but found that at low speeds I could stall the blade and the belt would slip. Looking around the shop, the turnbuckle was sitting there suggesting itself for this use. Clearly, this was what this turnbuckle was created to do!
I figure one day I might swap out the pulleys and vee belt for a toothed belt and eliminate that issue, but it has not been enough of a priority to actually do it. It's on the list...

Thanks, I appreciate the comments!

[misterfxt]

Nice job. Does the heat of the bandsaw blade ever cause any issues with the urethane wheels ? I ask because I want to do something similar.
Jerome

[alanganes]

If there is any issue with heat on the urethane tires, I have not see one. I used the urethane as that is what seems to be the popular choice these days, and the tires on the saw when I got it may very well have been original. They were ancient, cracked, pretty hard, and generally icky.

That said, I don't run this all day like someone in a commercial shop or whatever and admit I am no expert. So I'd not say it can't happen but I think if the blade was getting hot enough to damage the tires you may have some larger problem going on.

[misterfxt]

Great, Thanks. When I needed new material to cover the wheels on my very old craftsman bandsaw, I used the rubber inside a bicycle wheel that covers the spoke ends. I cut matching ends while overlapped , glued with yellow automotive weatherstripping adhesive. I put a couple slices of newspaper over the glued joint and put some long rubberbands around the whole shebang.I was good to go. That was 13 years ago and the rubber material is still in good shape. I am however looking through the alleys in my travels for another discarded bike for some new raw materials. Alley shopping is my favorite type of shopping but it's getting tough
to beat the scrap metal guys.
Jerome