Maximum Turning Capacity

intjonmiller

intjonmiller

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Practically speaking, what is the maximum turning capacity of a 10" Logan lathe? The brochure for my 850 says: Swing over bed and saddle wings: 10 1/2". Does that mean I could turn down a 10.5" part (10.5" before turning)? Or are there other limitations, such as how far I can retract the cross slide and compound?

I'm not with the lathe at the moment. I have a lot of down time at work lately, so I'm drawing up some plans. I should probably be more patient and just try to measure things when I get home, but I figured it would be good to hear any other considerations that may not have occurred to me.

For the sake of my current project I only need it to be a couple inches deep at that maximum diameter, in case that makes a difference (like reaching just that far with a specially ground tool or something).
 
That diameter is not the diameter of say, a shaft 2 feet long. That shaft would need to be smaller, because it would have to clear the cross slide. That 10.5 would be the disc it would spin without hitting the ways and "wings" as they call them, the extensions of the carriage. I suspect the shaft diameter max would be about 7", but I don't know. Someone with a lathe like it and a tape measure, or you when you get back to it could give that limit.

Many brochures also give the swing over cross slide as well.
 
The short answer is no as Tony said. That said I have turned 12" on my 12x36 lathe. I had to turn the QCTP to mount a boring on the side facing me.
 
Like I said, I was talking about a shallow disc. I realize that clearing the cross slide is a further restriction. I was just asking about being able to creatively turn the absolute maximum diameter on a Logan lathe (thus the location of my post and the specific wording about a Logan lathe (correct me if I'm wrong but they never made a gap bed lathe) and a shallow disc).

As for the other measurement I wasn't currently asking about, it looks like the max from the center to the cross slide with the cross slide way/leadscrew cover removed (I would replace it with masking tape or something for such an operation, as obviously when trying to do a part of maximum diameter there would not be much cross sliding needed) is just barely over 3.5" (say 7.2" diameter).
 
About 10-3/8" dia. if you turn your QCTP and compound around and use a backwards boring bar to reach along the part.
 
My instinct was pretty close, although immaterial to your quest. Just remember, however you have to go to reach it with a cutting edge, you're likely at a leverage disadvantage, so would be wise to avoid heavy cuts.

And of course, you will need to watch out that you don't run over your jaws if you manage to chuck this piece. If the OD needs to be machined over the full length, of course you will have to flip it around, so plan accordingly.
 
This is a contact wheel for a belt grinder, which I will first cast in aluminum and then machine true, so I'm planning on having a recess in the sides, allowing me to chuck it on the center section, leaving the full perimeter clear for machining.
 
I came up a 1/4" to big the other day when i need to turn an outside edge :headache:
 
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