Lathe Chuck Attachment Methods.

[egaParticipant @ega]

Posted by Andrew Johnston on 18/04/2017 20:42:05:

It's a shame my name was spelt incorrectly though. At least my name was correct on the front cover

Yes, I see they gave you an E for effort! I think it was right in the contents section so two out of three…

[Martin KyteParticipant @martinkyte99762]

I think most of the postings have covered the question.

I do have one thought to add regarding the Myford and similar lathes. Primarily the Super 7 and it's ilk are centre lathes where work is either turned between centres in the spindle and tailstock tapers or in collets, again using the headstock taper as a reference surface. Chucks being a secondary option. The threaded nose allows the use of a closing nut for collets and is available, with the register to attach scroll chucks. I know things have moved on and as turning between centres and faceplate work are less heavily relied on the use of scroll chucks has perhaps dominated perhaps masking their less important historical role in lathes of this type.

regards Martin

[egaParticipant @ega]

There is a useful discussion of this topic in Cliff Bower's Book of the Lathe and his conclusion is worth quoting:

"The possibility of making special attachments for the spindle nose should be borne in mind by the lathe purchaser. If it is expected that many of these will be required, the screwed or flanged types are preferable. If standard work-holders are to be used, which is highly probable, and it is expected that these will have to be changed frequently, the tapered type of spindle nose offers advantages because of speed with which attachments can be mounted and removed."

This is an old book from 1955 and I understand the Camlock came into use after this date.

[Mike BondarczukParticipant @mikebondarczuk27171]

Hi Roger,

The Hardinge taper has two positions, and turning the chuck clockwise sets it up for normal forward rotation work and turning the chuck anticlockwise sets it up on the other side of the taper keyway for anti-clockwise rotation.

Would not recommend allowing the chuck to reset itself and always stop the motor and then turn the chuck, but do agree that I cannot think of any reason why the chuck should turn backwards, so to speak, as patron g off is very easy and safe and threading is straightforward with the proprietary Hardinge system.

Mike

[SillyOldDufferModerator @sillyoldduffer]

Posted by Mike Bondarczuk on 19/04/2017 10:49:50:

…

but do agree that I cannot think of any reason why the chuck should turn backwards, so to speak, as patron g off is very easy and safe and threading is straightforward with the proprietary Hardinge system.

Mike

Mike's comment left me wondering "why is reverse needed at all" so I did a search. Practical Machinist has a surprisingly long list, including:

Quicker not to disengage half-nuts when cutting short threads; parting-off; grooving; boring in difficult materials such as bronze; cutting some metric threads; many internal operations; tool-post grinding; chamfering; winding springs; making matched inside and outside tapers; right-hand internal threading; tapping (or rather removing the tap under power); quick stop (not all lathes); and my favourite "unwinding a trapped shirt-sleeve".

One good point made about internal turning is that it's easier to see what you're doing with the lathe in reverse and an upside down tool . Also, running in reverse, it's possible to work out from an internal shoulder.

Dave

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