Get Your Variable Frequency Freak On
January 15th, 2009Versatility is Now Relatively Cheap
I am just starting to understand how wonderful a variable frequency drive (VFD) is.
While I was reading up on band saws, I noticed that Grizzly made a fairly inexpensive saw that cut both wood and metal. Naturally, I had to check into it. It turns out they take plain old wood band saws and add 3-phase motors and VFDs to them. That’s it. That’s the whole secret.
This is interesting, because while I was shopping around, it occurred to me that I might be underbuying by getting a saw that wouldn’t cut metal. I have plenty of metal-cutting technology, but it seems to me that there are some things a bandsaw could do that other types of tools can’t. Imagine cutting a lap joint into a bar of metal. I have no idea why you would want to do this, but you might. You’d need a bandsaw or a milling machine.
It seems to me that a metal-cutting bandsaw could function as a crude mill for some operations. That would be a nice capability to have.
It occurs to me that if I get a big ol’ wood band saw, the worst-case scenario for metal is that I might have to find a used motor and VFD later. That would sure beat forking out for a new saw and selling the old one.
Isn’t technology interesting? And I wonder if VFDs will drive the price of used metal-cutting saws down, too.
As for my earlier idea, about buying a bench drill press and adding a column, the wisdom of the approach seems to depend on the model. For a Delta, it’s cheap. For a Powermatic, a new column can cost something like a thousand dollars. Why? Search me. Maybe they’re made of gold.
January 15th, 2009 at 4:42 PM
The blades are different, too. Steel-cutting blades have much finer teeth.
But you have stumbled upon an important principle: the difference between steel-cutting and wood-cutting tools is speed and blade type, and (sometimes) rigidity of structure.
Your miter saws have universal motors. You can get a speed control for a universal motor, which is quite different from a VFD, crank the speed down, and substitute a steel-cutting blade for the wood-cutting one. At that point you have something called a “chop saw”, useful for chopping (!) light angle into pieces suitable for welding into various projects. It might be a good thing to do with the 10″ saw once you have the 12″ set up so that it’s convenient.
Regards,
Ric
January 15th, 2009 at 4:51 PM
I have a dry cut saw, so I won’t be needing to drive swarf into my miter saws’ plastic parts.
January 15th, 2009 at 8:53 PM
I can’t imagine that you can really get enough speed range with just a VFD to enable cutting both steel and wood. The couple of VFDs that I’ve set up were configured for a minimum of 10 Hz to a max of 120. That’s only 12:1, and the motor doesn’t have much power at 10 Hz. The saw really needs a two-speed gear transmission. They do exist, our PowerMatic has one, and my cousin has a 12″ Delta that has that feature.
January 15th, 2009 at 10:44 PM
I have a 9″ band saw that I use to mill Mesquite and Live Oak to usable lumber.
You’ll need to make some kind of cradle that slides in the saw guide slot. I made mine about 16″ long and with the ‘fence’ secured with dowels, and the holes drilled so you can cut 1″ slabs by advancing the fence one set of holes each pass.
I use 3/8″ metal blades with the coarsest cut available.
January 16th, 2009 at 6:24 AM
The right tool for the right job:
One of my former coworkers tried opening a can of chef boyardee raviloli with a band saw once. Apparently metal filings will ruin cheap pasta.
But that bandsaw was awesome.
January 16th, 2009 at 8:11 AM
J, take a look at this and tell me what you think: http://tinyurl.com/7u7xj9
It says the Grizzy saw will go from 10 fpm to 3500, but it doesn’t mention power loss.