Lathe improvements?

[JasonBModerator @jasonb]

Can’t see what the problem is. You could turn the larger diameter on a short stub of material, so not going to be anymore cutting force turning it on a longer bar. Assuming you don’t go silly and hang 3m lengths out the back. Start up load not a lot different to having say a 9″ dia part on a faceplate.

[Niels AbildgaardParticipant @nielsabildgaard33719]

The problem is bending stiffnes of spindle between the bearings .

The two headstocks shown before have same length between bearings

Bending stifness is a power 4 function of diameter

The 180 comes with a 30mm spindle and have a 21mm hole

Bending stiffnes 61 in some strange units

The 210 have a homemade 60mm spindle with a 49mm hole

Bending stiffnes 720 in same strange units

 

Important for onset of chatter and surface quality

 

 

 

[Niels AbildgaardParticipant @nielsabildgaard33719]

A 210 and 180 from same well reputed house

Amount of cast iron,steel and machining is almost the same.

Price not very different.

Lost opportunity

[Author]

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