How to avoid running into my chuck on power feed.

DavidR8 said:
On my 10K I did some experiments to get a feel for how many turns of the clutch knob achieved engaged the clutch.
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This is pretty much what it takes. I was terrified of using the power feed, but eventually sat down and just put an afternoon into getting a feel for it. Mark a shoulder on some work, nowhere near the chuck of course, and practice using the feed and disengaging in time. Start with the slowest possible feed, and work your way up. It doesn't take long to get a feel for it.

Once you're no longer worried about running into the chuck (say, a week's worth of projects involving the power feed), then start looking for ways to make disengaging the feed more repeatable. One of the simplest is to use a dial indicator clamped to the ways: when the needle hits the 0 (or whatever mark you are using), disengage. A DRO can be used for the same purpose, though it is a much greater project to install. The simplest method is to use a sliver of light between the tool and the work, the carriage and the stop, whatever - this is of course going to be lathe- and setup-specific, but basically you have your eye near the tool (not on a dial indicator or DRO), watching an ever-diminishing crack of light, and when the light vanishes, disengage the feed. As always, practice with a dry run (no power, tool not actually cutting) to verify when to disengage. With a shoulder, I tend to err towards early disengagement on initial passes, with the final pass establishing the shoulder completely - a slightly heavier cut but only for .010 or so.

Side note: pretty surprised nobody has punted with "dog clutch!" yet
 
twooldvolvos said:
"What lathe do you have? Does you lathe have a factory carriage stop that automatically disengages the power feed?"

I have a south Bend 10K. In the picture you can see my apron and carriage stop. I do not think the lathe is designed to disengage the power feed if the apron hits the stop. Please correct me if I am wrong.
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I'm not familiar with 10K, but it looks like a carriage stop for manual turning. There are lathes that have a special mechanism designed to disconnect the power feed when the carriage reaches a certain point. If your lathe doesn't have this feature I wouldn't use a power feed and rely on a manual stop.
A simple DIY manual spindle crank would be a way to go.
 
Nogoingback said:
You can power feed just short of the stop and manually advance the carriage the rest of the way to the stop.
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Use a dial indicator and use the automatic feed until you are within 0.050 of the stop, then switch off the autofeed, and feed until the dial indicator reads 0.000.

The safeguard against crashing your lathe is being attentive to what you're doing.
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The same standard applies to mils, shapers, grinders, and especially saws.
 
I set up a dial indicator to show me where I want my cut to stop. Usually set it up so it the dial makes a full turn and then I stop on 0. Watch the dial come around and disengage the feed some amount before zero, then turn it in by hand. As you practice you can get it to stop inside .010 with ease.
 
Mitch Alsup said:
Use a dial indicator and use the automatic feed until you are within 0.050 of the stop, then switch off the autofeed, and feed until the dial indicator reads 0.000.



The same standard applies to mils, shapers, grinders, and especially saws.
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Great minds think alike. You beat me to it!
 
In our freshman year of high school, the machine shop teacher had the kids whom first started on the lathe cut from headstock to tailstock. It means that you must use a opposite shaped bit and run the feed screw in reverse. It does not mean that you can take a coffee break. However, it sure is a lot less sweat, especially in this case, on the shop teacher. Think about it, the lathe does not care. The end result is still the same. Even Joe Pie sort of does the same thing except it was with threading.
 
twooldvolvos said:
As a new lathe owner, I am very leery about running my cutter into my chuck, especially if the power feed for the apron is engaged toward the chuck. So what are the safeguards against doing this? I have a carriage stop. Would the clutch slip if the apron hit the stop?
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There are no fail safe solutions to your question . You never feed into the stop even if the machine has a clutch , bad things can and will happen . A manual machine will always need an attentive operator . Feed up close to your stop and trip the power feed , then hand dial it to the stop . An indicator , travel dial or DRO is a helpful accessory but not needed and you'll get more comfortable doing this with more machine time .
 
silence dogood said:
In our freshman year of high school, the machine shop teacher had the kids whom first started on the lathe cut from headstock to tailstock. It means that you must use a opposite shaped bit and run the feed screw in reverse. It does not mean that you can take a coffee break. However, it sure is a lot less sweat, especially in this case, on the shop teacher. Think about it, the lathe does not care. The end result is still the same. Even Joe Pie sort of does the same thing except it was with threading.
Click to expand...
He does that running the lathe in reverse.
We cannot run our SB lathes in reverse, lest the chuck comes off.
He would have to use the reversing lever to machine away from the chuck, like cutting LH threads.
 
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