“Intentionally underpowered” Atlas lathe motor

All comments are much appreciated! I think I got an idea now of what sort of new motor I need (well, actually I do have a 3/4 hp non-original motor that came with it, but I would feel more comfortable with a bit less power, also for the reasons outlined above).

Larry$, would you mind sharing what type of brake you are using?
 
Having a lathe that stops instantly will not eliminate all safety risks. Operating any machine tool entails some risk. Plenty of ways to get injured if one is not paying attention. Good reason to never operate a lathe or milling machine when tired or distracted. Even an unpowered machine can be potentially dangerous from sharp exposed tool bits and cutters and so forth. Learn your machine well and approach it with a safety first attitude always.
-Mark
 
xyz07 said:
All comments are much appreciated! I think I got an idea now of what sort of new motor I need (well, actually I do have a 3/4 hp non-original motor that came with it, but I would feel more comfortable with a bit less power, also for the reasons outlined above).

Larry$, would you mind sharing what type of brake you are using?
Click to expand...
Trying to make a foot brake for your lathe would be more trouble than it is worth.
 
If the idea of a motor running full speed makes you nervous, you might want to consider a variable speed motor system. A welcome improvement to any fixed-speed lathe, IMO
If you're like me, once you have it, you won't want to go back :)
-M
 
I really don't think the amount of power will make any difference on the safety. When something goes wrong it happens so fast that you can't really do much about it. Until you get used to running it just use the gearing for lower speeds. Being able to vary the speed between what you can get using the gearing might be helpful. The one thing about it that seems best is being able to dial up the speed as the cutting diameter decreases.

The braking system on my lathe is factory, not something I did. A pedal bar runs along the the bottom of the machine. When stepped on it cuts power to the motor pickup coil and engages a mechanical brake. It stops the spindle almost instantly. (Not something you should do with a threaded chuck) But there is still the issue of the response time of the operator. You can see the brake being used by some of the YouTube creators just to not have to wait for the machine to spin down. Some bigger lathes use a combined clutch and brake lever that allows the motor to keep running but stop the spindle. Adam Booth has one.

A lot of new lathes come with a shield that covers the chuck. You could fabricate one. Getting hit by the chuck jaws seems like something that could easily happen. They often have a switch that prevents running the lathe with the guard up. Bigger lathes don't seem to come with them but the small hobby lathes often do. Work safe, wear those safety glasses.
xyz07 said:
Larry$, would you mind sharing what type of brake you are using?
Click to expand...
 
I would also be of the thought that under powering the lathe is not the best of ideas. My 1916 Seneca Falls Star lathe has a 1 hp motor. You can always control speed and torque with a VFD, or even leave the belt a bit loose if you're afraid of crashing it.

If yours is like most South Bends the flat belt can be tensioned or loosened relatively easily. I have on several occasions loosened the belt on my machine when trying to get into tricky places. There's still enough tension to make light cuts, but it's loose enough that the spindle will stall should you do something you shouldn't.

As mentioned you should be comfortable using the machine before you try it. Having respect for it is quite a bit different than being afraid of it. You might want to find a friend who's familiar with machine tools to give you some initial instruction and guidance. If that isn't practical you can always watch some of the hundreds of instructional videos on YouTube.

There are several out there by Lyle Peterson aka tubalcain. He's an excellent instructor and spent many years as a high school Industrial arts teacher. In my opinion he's one of the best on YouTube. He takes time to explain each operation, and the reason for doing it. Keep in mind he was training potential professionals for over 30 years. Here's a link to a video of what he offers. This particular video is just an index of the over 700 videos he has made. Many of the actual videos are on the maintenance and operation of a South Bend 9" lathe.

INDEX OF TIPS MACHINE SHOP TIPS & COURSES tubalcain - YouTube
 
Once again, I would like to thank everyone for great advice. I will likely go with a 1/3 hp motor, especially since I already have a 3/4 one. I do understand the arguments about life being a risky proposition in general, and the best thing to do being to learn how to use the lathe safely, but I am also a great believer in doing my best to stack the chances in my favor :)). After all, we all make mistakes (whether pros or amateurs); this is part of being human. Therefore, I firmly believe it makes sense to take measures reducing the potential "cost" of these mistakes down to an absolute (feasible) minimum. Of course, in this particular case these measures should result in a reasonable compromise, where the usability of your machine doesn't suffer too much, and that was the rationale for creating this thread.
 
Am I the only one who tries to measure the part while my lathe is still slowing down?! ;)
That's the one reason I think a foot brake could be helpful.
Robert
 
I have a Craftsman 12x36, a 101.27440. It was originally rated for a 1/2 HP motor. I have a 1/3 HP motor that will slip belts but has never stalled. To my thinking, a 1/8 HP motor wouldn't be good for much of anything heavier than a middlin' size fan. 1/4 HP is about as small as I would go on a machine. But that's just my thinking. . .

.
 
XYZ, you can always change motors later. Maybe on that type of lathe that's all you need. I have no experience with them.
Be safe, have fun.
 
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