Tractorsport Flowbench Forum Archive

Posted: **Thu Apr 30, 2009 11:43 pm**

Hi all, I know that the HF controller will not work on all types of motors, just don't know which it does work on! I am in need of a bandsaw for cutting some 1/4 inch AL plate and other size ferrous metals. I have a band saw for wood and was thinking if I could slow the motor down and get a proper blade for less than a new band saw, why not? Can anyone shed some light on this for me? Thanks -- Doug

Posted: **Fri May 01, 2009 12:16 am**

Doug,
Quote from the Harbor Freight web site about the speed controller:

"Get better results and longer bit life when routing tough woods, plastics, even aluminum.

Plug your router into the control unit and you instantly have a variable-speed tool
Works with any universal AC/DC brush type motor, 15 amps and under

Will not work with soft- or slow-start motors. Router sold separately."

John

Posted: **Fri May 01, 2009 11:56 am**

Hi John, I read through the HF manual but that didn't answer my question, that's why I turned to the smartest people in the world: all of you guys here on the Forum. :p Are the motors used on a typical (re: Craftsman 10 inch) bandsaw "...universal AC/DC brush type motor, 15 amps and under..."? I can read the tag on the motor to determine the motor is under 15 amps, but how do I find out about "...universal AC/DC ..."? I guess I should have paid more attention in the EE classes back in school. Hmmm! Maybe I did and just don't remember? Thanks for the help! -- Doug

The more I thought about it, the motor used on the old lathe I have (at least most of the parts are there) is almost the same motor so maybe I could use that for some simple work there too? I'm not trying to do fancy stuff, but sometimes being able to "turn" something helps with my construction "projects".

Posted: **Fri May 01, 2009 2:16 pm**

Doug,
If when you turn your band saw on it jumps a foot off the ground and the blade about throws off the rollers then no it is not a slow or soft start up :;):

If the blade just slowly picks up speed then it is most likely a soft start. My router is a soft start so it won't twist out of your hands when you start it.

Now we need to find out if your band saw is brushless or has brushes in the motor. It should be a/c if you are plugging it into the wall - it does not have to be both.

John

Posted: **Sat May 02, 2009 12:43 am**

Here's the specs on the bandsaw motor and 2 others I have sitting around in equipment that isn't working. All carry Sears labels. None are soft start as all are quite old.

Motor on the band saw (only one currently working)
Label reads: Capacitive start, AC motor.
General application: wood lathe, band saw, drill press
1/2 "B" HP, 1725 rpm
SF 1.0 SFA 8.8
Reversible, sleeve bearings

Motor on a Jointer/Planer
Label reads: Capacitive start, AC motor.
1/2 HP, 3450 rpm, 115 VAC
SF 1.0 SFA 8.4, sleeve bearings
Partial label looks like the "Reversible" label above

Motor on an old wood lathe
Label reads: General Purpose Motor
1/3 HP Split Phase
115 VAC, 60 cycle, 1 phase
6.0 Amp, 1725 RPM

I can't see inside enough to tell if there are brushes on any of them. There are NOT any apparent access holes where I would have guessed brushes would have been on any if the 3. Anything I should look for? -- Doug

Posted: **Sat May 02, 2009 1:09 am**

Doug,
I found this at an electric motor forum:

"Cap-start motors usually have a centrifugal switch that drops out the start capacitor at about 2/3 - 3/4 of full speed. If you try to reduce the fan speed below the centrifugal switch's cut-in speed, you will get the effects complained of.

I don't think that there is any easy answer here, short of changing the fan motor for one which is more amenable to speed control. A shaded-pole motor would be a good start - these can be speed controlled quite easily with an inexpensive electronic controller which is similar, but not the same as a light dimmer."

Going off of that I do not think you can speed control the capacitor start motors.

John

Posted: **Mon May 04, 2009 11:52 pm**

Posted: **Tue May 05, 2009 12:37 pm**

Hi John (jsa), I had figured out that they were No Go, but what do I look for on the tag to find a "good" one? Will it say it is has Brushes, or ??? Can I see the brushes from outside? I don't use the band saw much now, so to make it dual purpose with a speed control and (needed) new blades seems like a good setup, especially if I can find a used useable motor ("cheap").

I also have a way of finding new uses for old things! :p

Thanks for the input (both John's)! -- Doug

Posted: **Wed May 06, 2009 12:41 am**

Hi John,
We use a wood cutting bandsaw all day for cutting alum plate. Just use a skip tooth blade with between 4 & 10 tooth per inch. remember less teeth for thicker material. They will last forever if you are carefull and will saw like crazy. If you knock the set off the teeth you are done and it will quit cutting. This is easy to to do if you try to cut curves that are to tight. You can get 3/8 wide blades at HF that work pretty good and cheap. We usually use 1/4" blade from Do-all because we cut scrap off of parts out of the mill after op1.

I have never come up with a way to cut steel on one of those though unless you want to shell out money for the carbide grit type blade. Lots of pulleys and idlers so you can keep the motor torque up for that kind of cutting.

Posted: **Wed May 06, 2009 1:10 am**

Posted: **Wed May 06, 2009 1:54 am**

As a general rule, induction motors are larger, run relatively silently and the rpm will be in the 1400 or 2800 range (for 50Hz) and 1750 or 3500 range (for 60Hz). Bench grinders, and drill press motors, bench saws. and band saws, are almost always of this type. Large non portable workshop power tools.

Ac/dc brush type motors always run at very high rpm, 18,000 to 22,000 rpm being typical. If it screams it's head off like most power tools , (or vacuum motors} chances are it will be an ac/dc brush type motor that is suitable to run off the HF router controller.

Electric drills, routers, portable electric saws, anything really small and noisy will almost certainly have a brush motor.

Posted: **Wed May 06, 2009 7:15 pm**

Doug;

I used a VFD (Constant Torque) on my one bandsaw and it works AWSOME, it is three phase but they do some nice 120VAC units about $180 us. An investment but on my old cast iron Delta unit with only blade changes and turn of the dial I can cut anything from plastic to steel.

Rick

Tractorsport Flowbench Forum Archive

Harbor Freight controller - Will it work on a band saw?