Slowing down a vertical bandsaw

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I just bought a Grizzly g1073 Its a 16" bandsaw made for cutting wood. I need to get this slowed down enough to cut stainless header tubes probably around 200-300fpm. What ways are out there for doing this  I know I could run a humongus pulley on the drive side and a very small one on the motor side. Or maybe how about making my own gearbox or something with a bunch of sprockets to make a speed reducer.  I know it is all possible but the math is beyond me right now. Right now It has a 1720rpm motor with a 2" pulley and then it goes to a 9" pulley and the wheels a 16" Thanks in advance Corey
Reply:Yes - the best way would be switching pullies. Call the manufacturer and see if they offer any. Also check the online sites for motors/pullies - like Grainger.com.  You might also check Mcmaster-Carr.John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:My 12" Craftsman bandsaw has the optional speed reducer which incorporates a jack shaft and cogged drive belt.  It might take more than a pulley swap to slow that baby down...That aint heat lightning in the neighborhood tonight...
Reply:Pullies are good.....or you could put a Hz frequency controller on it like I did with my 23" Pehaka.I have the pullies on it to run slow enough for 90% of what I do but to be able to adjust my speed on the fly in a matter of seconds is fantastic.The only drawback that I have found is that some of the torque goes away from the motor at the very slow speeds but it has never been enough of a problem to worry about. A good blade and the proper feed speeds and it cuts outstanding.Here is a link to the Hitachi controller that I installed on my saw.http://www.driveswarehouse.com/Drive...00-002NFU.htmlAt $180, I won't ever screw with pullies or gear boxes again.- Paulhttp://all-a-cart.comWelding Cart Kits and accessories
Reply:http://cgi.ebay.com/ROUTER-SPEED-CON...QQcmdZViewItemWhat about something like this? They are all over ebay and their advertisements talk about being able to control the speed of any power tool. Id imagine it might work quite well for this.
Reply:Just hold the blade with one hand, and feed the metal with the other. If you grab hard enough, the blade should slow down....LOL.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:That says its for 15amps and under and If i run on 110v its like 24amps. The other controller posted looks good but Ive heard that If you slow down a AC motor you will burn it up. I called around on pullies yesterday but the most I can gte it slowed down is to like 650fpm. So I think I may do that then try and find a speed control that will work for less than $200. Does no one know how to do the math on how to slow it down with some chain and sprocket or gears?
Reply:http://www.thinkerf.com/bandsaw_feeds.htmhttp://www.owwm.com/Math/SFPM.aspThese might be helpful...maybe.  Formulas are included for lots of bandsaw calculations.Last edited by smithboy; 06-06-2007 at 02:11 PM.Smithboy...if it ain't broke, you ain't tryin'.
Reply:Originally Posted by fordsux8269Ive heard that If you slow down a AC motor you will burn it up.
Reply:I think a controller would work well in this situation vice changing pullies, doing math and swapping out to get the correct RPM.John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:Different types of controllers are needed for different types of motors.  A DC motor uses a different controller than an AC induction motor, which uses a different controller than an AC universal motor, etc, etc, etc.Hey, Paul (ZTFab), you do realize that the $180 Hitachi controller L100-002NFU you web-linked to is for a 1/4 HP motor and 240V-1.4A output?  That low output power could be why you bog the saw at low speed (or at higher speeds if you have a heavy or even moderate feed rate going).  I'd figure a 23 inch industrial bandsaw would have a 3-5 HP induction motor on it, and you'd use the appropriate VFD controller for the motor.   Something like an L100-030, L100-033, or L100-040 VFD controller.The little router speed controllers typically will not work on an AC induction motor, they are made for the little AC universal motors like on a router or other screamin' motor handheld power tool.To the OP, to run your bandsaw with 16 inch wheels at ~200 fpm, you need to turn those wheels at about 48 rpm.  With a 1720 rpm motor, you need a reduction ratio of about 36:1.  That's a little tough to do in one reduction stage.  For reference, right now you have a 4.5:1 reduction ration with your pulleys and are at 1600 sfpm.If you run three reduction stages of 3.3:1 each, then you will be at a total reduction ratio of 36:1.  You could get that with three stages of 3 inch and 10 inch pulleys.  Swap the 2 inch motor pulley for a 3 inch, and swap the 9 inch wheel pulley for a 10 inch.  Then just rig up two more stages in between the motor (initial pulley) and the wheel (final pulley).motor - 3:10 - 3:10 - 3:10 - wheelWatch out for the torque multiplication on the shafting and pulleys and connections and belts (or chains, sprockets, and shafts if you go that route).Yeah, it's do-able.  But a VFD would be a -LOT- easier.
Reply:I have a 14" taiwan vert bandsaw made for wood applications.  I put a 1720/1HP motor on it, and changed the pulleys to the biggest I could possibly shoe-horn in (almost touching each other) to slow it down for occasional metal cutting.  I've cut everything from 2" thick aluminum billet to some common steel stock and sheet metal.  I bought a few quality blades (3'16", 1/4" and 1/2") and just don't push it.  I let the blade do the work.  It cuts fine w/o overheating and I'm still using the original blades.For industrial, daily-driver applications, I'd have to do something different though.Hobart 140 Handler w/ gasHyperTherm Powermax 380 Plasmaoxy/acetylene
Reply:Originally Posted by MoonRiseHey, Paul (ZTFab), you do realize that the $180 Hitachi controller L100-002NFU you web-linked to is for a 1/4 HP motor and 240V-1.4A output?  That low output power could be why you bog the saw at low speed (or at higher speeds if you have a heavy or even moderate feed rate going).  I'd figure a 23 inch industrial bandsaw would have a 3-5 HP induction motor on it, and you'd use the appropriate VFD controller for the motor.   Something like an L100-030, L100-033, or L100-040 VFD controller.
Reply:Dang, someone beat me to it.
Reply:ZT: I can't remember the parameter off the top of my head, but you can turn on 'torque boost'.  Causes the drive to output more voltage at the lower frequencies.  ( I have the same drive on a drill press, but it's a 2hp model ).  Works like a charm.  Got to be careful though, torque boost can cause the motor to heat up ( higher voltage ) if it's not spinning fast enough to cool itself.  Or put a fan on it.