"swing over bed" Definition

Jan 04, 2004 29 Replies

Just don't forget that there is swing over bed and swing over carriage, which are usually VERY different. On a wood lathe you get more room because there is no carriage in the way. So be sure to ask which swing you are talking about on a metal lathe. A machine that can swing 20" over the bed but only 16" over the carriage isn't going to work to turn that 18" chunk of steel.

In the US, swing of a lathe is the diameter of the largest workpiece. I gather that in at least parts of Europe, the swing is the maximum radius, half the diameter. I don't know which definition is used in the UK.

Joe Gwinn

Some time ago we had a job to turn a 20 inch by 6 foot chunk of steel on a Monarch lathe with 18.5 inch over the carriage. The first cut was 1 inch deep to get to 18 inch diameter to go over the carriage. The chip was about 100 feet long before the operator broke it deliberately, deep and slow pass but it worked perfectly.

I'm missing something - HOW did you turn a 20" piece with 18.5" of clearance?

Guessing... move carriage to the right of 20" piece. Make sure cutter is ahead of the carriage and you're cutting off enough material to clear the carriage as it advances...

A 20" dia piece needs 10" of clearance. 18" dia needs 9" of clearance. 18.5" over the carriage will handle a 37" diameter! Let's get it right, guys. :>) phil k.

That would work. If the tailstock center could extend over the carriage.

The 18.5" is the diameter over the carriage.

A 20" dia piece needs 10" of clearance. 18" dia needs 9" of clearance. 18.5" over the carriage will handle a 37" diameter! Let's get it right, guys. :>) phil k.

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Also don't forget to have the carriage at the starting position BEFORE loading the 20" x 6' blank.

I sometimes forget to check for full carriage travel before threading a short piece between centers, where the tailstock and live center bearing intrude.

I haven't run the carriage into chuck jaws but the trade school students who used the lathe before me obviously did, many times. I bought new chucks. The micrometer carriage stop makes a good safety barrier near the chuck though I use collets or small 3/4/6 jaw chucks on 5C mounts if possible.

That would work. If the tailstock center could extend over the carriage.

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I've read that the width of the carriage is one of the few disadvantages of the Hardinge, compared to the South Bend 10L.

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