"swing over bed" Definition

Correct, "swing" in machine tool talk is radius (like a swing hanging from a tree). "Swing over carriage" is another important measurement, on some lathes the carriage gobbles up a lot of swing.

In the US. In europe that would be a 3" swing.

Note this is over the *bed*, not over the carriage. It's the absolutely biggest thing that could be swung, between centers, in the lathe, with everything else out of the way. Useful for comparison sake.

Jim

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Cliff Knight wrote: Correct, "swing" in machine tool talk is radius (like a swing hanging from a tree.(CLIP) ^^^^^^^^^^^ Cliff, too bad you didn't stop right after the word "correct." Pal had it right, so "correct" is correct. But swing is not a radius. The radius of the maximum size his lathe will turn is 3"--the swing is 6", the DIAMETER. The illustration of a swing hanging from a tree merely adds to the error of calling the radius the swing.

Yes. In the US. In the UK, the swing would be 3 inches.

We go by diameter in the US, and they go by radius in the UK.

Ed Huntress

Not to confuse things, but if I understand correctly, in England they use the radius as the swing. In other words, in the original post it would be a 3" swing (in the States it would be a 6" swing)......

Well, if you want to get specific, wouldn't it be a 75mm swing in the UK?

Regards,

Robin

Right. Americans are lazy. It is easier to state the largest diameter piece that can be turned rather than requiring the worker to divide by 2 (or multiply by 2) to find out if a piece of stock will fit. Doing the math (and decisions which one to multiply or divide), much too hard. :-)

Gary

Not if it's an old lathe.

Ed Huntress

Yep. We're too busy drinking beer.

*Cold* beer.

From refrigerators that actually work.

If all I had to look forward to at the end of the day was a warm beer in a house with no central heating, I wouldn't be in a hurry to get home either. I sure would be dithering along, doing odd sums and long division by hand in the shop...

Jim

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Should it not be 76.2mm?

Cheers

Eric

The last time I looked, English lathes are defined by centre height. They don't refer to it as the swing.

Steve R.

Anyone know when the UK converted to metric?

Hey, give the Brits credit for making a beer good enough to drink when it's only 62 or 52 degrees! Now if we could only get them to fix food other than BOILED.

Cheers.

jim rozen wrote:

Heh. Yet another reason to just stay at the darn shop and do square roots by hand instead of going home.

:)

Jim

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Thats what I have always been told. Does not necesarily mean you can do anything with it once you swing the max though. I ran into that with my 13 inch JET with gap that supposedly allows swing of up to 22 inches. I can face things up to a certain point on the 22 inch diam but working on the circumference edge is not possible without jumping through a lot of hoops and making special tooling etc for access. The cross slide does not retract far enough to allow proper or should I say decent access to the circumferance of the parts your turning, ot to get within 3 1/2" of the part during facing due to the extended castings of the apron .

My max swing is 13" and if there was one layer more paint on my apron it would have scrubbed it when I swung a 13" diam wheel.

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Might as well get in this perennial semantic free-for-all. Actually, American lathes (and perhaps British) aren't all that consistent -- or at least, were not in the past. For some American lathes, the swing is the biggest diameter that can be turned. For others, it is the twice the distance from the center to a line drawn across the ways. For example, my

12" clausing, can actually turn something 12.75" in diameter (but not over the saddle). I've seen other, older, American lathes that understated their "swing." To add to the confusion, most gap-bed lathes can turn something significantly bigger than their "swing." Does any one have even more confusion to add to the discussion?

Boris

Leo, you are of course correct--early morning senior moment...

-cliff-

'Swing' is the radius, not diameter. Think of how long a pendulum would be swinging from the spindle. Same wrt crank length on a crankshaft.

'Swing' is the radius, not diameter. Think of how long a pendulum would be swinging from the spindle. Same wrt crank length on a crankshaft.

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