Swing Over Bed ????

[carma1]

G'day all,
In term of lathe specs what is meant by the term "swing over bed". Its obviously a measurement of something, but of what??? Also what does this figure equate to when comparing lathes ie: Vicmarc VL300 is 600mm. How does this compare to a Carbatec with 400mm. Which is better/worse & why?
Cheers
Mark :confused:

[macca2]

Mark,
The term swing over bed refers to the size of bowl that can be turned on the lathe with the headstock in the normal position. Some lathes have heads that rotate to 90 degrees so the swing over bed then no longer applies. Also some lathes have outboard turning facilities on the other side of the headstock. Again the swing over the bed does not apply.

macca

[HiString]

Alway take care to determine whether "quoted" "swing over bed" figures are the actual distance from the spindle axis to the bed rails or the largest diameter that can be turned over the bed............one being the radius, the other the diameter.

I have seen both being used.

:cool:

[DanP]

As far as I recall from my apprenticeship days, the correct method is the measure from spindle centre to bed. I seems to be a marketing thing to say the maximum diameter you can turn. Makes 'em sound bigger.

Dan

[carma1]

Thanx for the help guys, your all to kind...
Cheers
Mark :)

[Zed]

then again in the gymnastics dept swing over bed has an entirely differnet meaning, sorry - i was gunn answer but there is nothing except humour to add to the above replies!

if you want to turn big stuff get one with a swivel head.

cheers

[rsser]

Took the words out of my mouth Zed.

Could do something with morse taper and hollow centres; oh and swivelling heads ;-}

[RETIRED]

The above answers are all correct in relation to bowls but it changes if you wish to do a large diameter spindle.

You have to subtract the banjo height, so suddenly 300mm diameter becomes in some cases down to 200mm and that is provided it is round. If square then even less.

There are ways around this but it involves using 2 banjos and a long tool rest at the extremities of the timber past the ends. Depending on length this is not really satisfactory because of flex in the rest itself.

Hope this makes some sense.