is it wise...

[Mark Needham]

Going bigger doesn't matter.
Do not go smaller.
What ever you eventually do, "Will be the right thing".
Don't listen to me, do your own thing, and be prepared to learn, or not.

 

[GL]

To illustrate the issue, I work for a place that builds trucks. We had a left over engine that was sold to a friend of our engine distributor to replace an engine in a farm tractor that had gone south. Our truck engine had higher horsepower and torque than the original, the instructions were not to pull more plow than before. A year later, the transmission in the tractor blew up - because he was pulling more plow than before. So the cautionary tale is, a bigger motor will take deeper cuts and generally be better than before, but other things in the system may be in jeopardy if you take cuts that seem to work now but not before. Bigger works, but don't blow up the rest of the lathe in the process. Your car will go faster than the speed limit - wisdom dictates the angle of your ankle to the throttle pedal.

 

[WCraig]

This is the lathe, right?

atlasTop.JPG

Are you having problems with the lathe stalling during cuts? That is, the work in the chuck stops turning? When that happens, is the motor stopping or is a belt slipping?

I'm a newbie and I've stalled my Atlas 618 several times. I'm intentionally using a crappy old belt from the motor to the countershaft. If I overload the machine, the belt slips which has saved me from a couple of 'unfortunate events'! I was told that the Atlas 618 is designed for a 1/4 or 1/3 HP motor although I have a 1/2 HP. I think that Robert D. is trying to say is that a bigger motor makes it more likely that gears will get stripped or other parts might break. Worse, you might get broken!

I think your lathe uses "3L" belts, as well. There is some maximum amount of power that such a belt can transmit. (Pulley sizes matter too. Bigger pulleys have more belt wrap and can therefore transmit more power.) For example, my Unisaw uses a matched pair of 4L belts for its 1.5 HP. A really large motor driving a 3L belt would be a waste; it would slip before the motor reached maximum load.

OTOH, if your lathe stalls when taking a light cut in soft material, maybe we can figure how to fix that problem*! What exactly is your experience?

Craig
* Eg, if your motor can run on either 115 or 230 volts, if it is wired internally for 230 but connected to 115, it will have way less power than it should. Correcting the internal wiring would quickly fix the issue. Or maybe you have a bad or inappropriate belt? Maybe a pulley is dished out? Maybe the belts aren't tight enough? Maybe one of the shafts isn't running freely and is wasting the motor's power? Etc...

 

[minsk]

This is the lathe, right?

atlasTop.JPG

Are you having problems with the lathe stalling during cuts? That is, the work in the chuck stops turning? When that happens, is the motor stopping or is a belt slipping?

I'm a newbie and I've stalled my Atlas 618 several times. I'm intentionally using a crappy old belt from the motor to the countershaft. If I overload the machine, the belt slips which has saved me from a couple of 'unfortunate events'! I was told that the Atlas 618 is designed for a 1/4 or 1/3 HP motor although I have a 1/2 HP. I think that Robert D. is trying to say is that a bigger motor makes it more likely that gears will get stripped or other parts might break. Worse, you might get broken!

I think your lathe uses "3L" belts, as well. There is some maximum amount of power that such a belt can transmit. (Pulley sizes matter too. Bigger pulleys have more belt wrap and can therefore transmit more power.) For example, my Unisaw uses a matched pair of 4L belts for its 1.5 HP. A really large motor driving a 3L belt would be a waste; it would slip before the motor reached maximum load.

OTOH, if your lathe stalls when taking a light cut in soft material, maybe we can figure how to fix that problem*! What exactly is your experience?

Craig
* Eg, if your motor can run on either 115 or 230 volts, if it is wired internally for 230 but connected to 115, it will have way less power than it should. Correcting the internal wiring would quickly fix the issue. Or maybe you have a bad or inappropriate belt? Maybe a pulley is dished out? Maybe the belts aren't tight enough? Maybe one of the shafts isn't running freely and is wasting the motor's power? Etc...

Craig, no i have not stalled it..i think the original 1/3 motor might have stalled. Usually if you stall its becuase you are takeing either to deep..or to aggressive of a cut. I was only thinking more hp so i could cut steel better, more aggressively.

 

[minsk]

To illustrate the issue, I work for a place that builds trucks. We had a left over engine that was sold to a friend of our engine distributor to replace an engine in a farm tractor that had gone south. Our truck engine had higher horsepower and torque than the original, the instructions were not to pull more plow than before. A year later, the transmission in the tractor blew up - because he was pulling more plow than before. So the cautionary tale is, a bigger motor will take deeper cuts and generally be better than before, but other things in the system may be in jeopardy if you take cuts that seem to work now but not before. Bigger works, but don't blow up the rest of the lathe in the process. Your car will go faster than the speed limit - wisdom dictates the angle of your ankle to the throttle pedal.

i work on volkswagen vans for fun. a lot of people like to put subaru engines in them...they often blow up their transmissions. . the stock trannys are not made for 210 hp and twice the torque.